Diet Tag

Ketogenic Diet Cut Liver Fat by 67% in a Randomised Trial

Key Takeaways:

• People with obesity who followed a ketogenic diet reduced their liver fat by an average of 67%, compared with an average reduction of 45% in both the Mediterranean and low-fat plant-forward groups – even though all three groups lost a comparable amount of weight.
  
• Around half of the participants following the ketogenic diet no longer met the criteria for prediabetes by the end of the study, compared with 29% in the Mediterranean group and 7% in the plant-forward group.
  
• Despite obtaining 73% of their calories from fat, participants in the ketogenic group showed no increase in blood fat or cholesterol levels, alongside the largest rise in glucagon and the steepest fall in blood insulin of the three groups.
  
  
  

Carbohydrate restriction appeared to add benefits beyond weight loss

A very low-carbohydrate, high-fat diet may deliver stronger metabolic benefits for people with obesity than either a Mediterranean diet or a low-fat diet, according to a clinical trial published on 27 August in the Cell Press journal Cell Metabolism. After four to five months on a ketogenic (or “keto”) diet, about half of the participants with obesity and prediabetes no longer met the criteria for prediabetes.

“We know weight loss can improve metabolic health in people who are obese,” says Samuel Klein, the study’s corresponding author at Washington University School of Medicine in St. Louis, Missouri. “Our data suggest that if you have high liver fat content and prediabetes, reducing carbohydrate intake can have important therapeutic effects on metabolism beyond just weight loss alone.”

The distinction matters clinically. Weight loss itself is known to improve metabolic markers, so the open question has been whether the composition of a diet contributes anything further once the amount of weight lost is held constant. This trial was designed to test exactly that.

Comparing three widely used weight loss diets

An estimated 40% of adults in the United States have obesity. Doctors often recommend low-fat, low-carbohydrate or Mediterranean diets for weight loss, but researchers have not known whether one approach provides extra metabolic advantages beyond the effects of losing weight.

The three diets differ sharply in how much carbohydrate and fat they provide:

• A low-carbohydrate diet, also known as the Atkins or ketogenic diet, greatly restricts carbohydrates. A ketogenic diet can include foods rich in saturated fat, including animal products.
  
• A low-fat diet, by contrast, can obtain as much as 70% of its energy from carbohydrates.
  
• A Mediterranean diet emphasises plant-based foods such as vegetables, olive oil and nuts, along with moderate amounts of fish and dairy.
  
  
  

To compare their effects, Klein and his colleagues enrolled 42 people with obesity, prediabetes and fatty liver disease in a clinical trial. Participants were randomly assigned to follow a ketogenic diet, a Mediterranean diet, or a low-fat, plant-forward diet. The research team supplied all of their food, and participants met with a dietitian every week to help them stay on their assigned eating plan.

That level of support is worth noting. Providing every meal and offering weekly dietetic contact removes much of the adherence variability that undermines free-living diet studies, which strengthens confidence that the differences observed between groups reflect the diets themselves rather than differences in how closely people managed to follow them.

Matching weight loss across the three groups

The ketogenic diet supplied just 4% of calories from carbohydrates and 73% from fat. In the Mediterranean group, 50% of calories came from carbohydrates and 35% from fat. The plant-forward diet provided 70% of calories from carbohydrates and 15% from fat.

Researchers adjusted calorie intake for each person so that participants in all three groups would lose about 10% of their body weight. Reaching that target took roughly four to five months.

By the end of the study, participants in every diet group had significantly reduced their body fat. Insulin sensitivity also improved across all three groups, helping the body control blood sugar more effectively. In other words, all three approaches worked – the question was whether any of them worked better than the others once weight loss was equalised.

The ketogenic diet produced the largest fall in liver fat

Despite similar weight loss, the ketogenic diet produced the strongest changes across several measures of liver and metabolic health. Liver fat fell by an average of 67% among people following keto, compared with an average reduction of 45% in both the Mediterranean and plant-forward groups.

The researchers also tracked participants’ metabolism over a 24-hour period by repeatedly analysing their blood. People in the ketogenic group showed the largest rise in glucagon, a hormone that helps reduce fat stored in the liver. They also had the greatest decline in blood insulin levels, another change that can help lower liver fat, compared with participants following the other two diets.

Together, the hormonal findings offer a plausible mechanism for the liver fat result: lower circulating insulin and higher glucagon both shift the liver away from storing fat, and both are the expected consequence of sharply restricting carbohydrate intake.

Blood fats did not rise on the highest-fat diet

One of the more counter-intuitive results concerned the lipid profile of the ketogenic group, whose diet contained by far the most fat and could include saturated fat from animal products.

“The most surprising finding was that participants in the ketogenic diet group didn’t experience an increase in blood fat or cholesterol levels despite consuming the most fat,” says Max Petersen, the study’s first author at Washington University School of Medicine.

Prediabetes improved most in the ketogenic group

After the weight loss intervention, about 50% of participants following the ketogenic diet no longer met the criteria for prediabetes. That compared with 29% of those on the Mediterranean diet and 7% of those following the plant-forward diet.

The researchers were careful to position dietary composition alongside, rather than against, current pharmacological options for people living with obesity.

“GLP-1-based medications have revolutionized the therapy of obesity. We now have a very effective pharmacotherapy for achieving significant weight loss,” Petersen says. “But in addition, our study shows that the specific composition of the diet can give you added benefits.”

What the findings mean for everyday practice

For healthcare professionals supporting people with obesity, prediabetes or fatty liver disease, the practical implication is that the content of a weight loss plan may deserve as much consultation time as the calorie target attached to it. Two people can lose the same 10% of their body weight and still arrive at meaningfully different liver fat and glycaemic outcomes.

This is the kind of nuance that clinicians increasingly need to be able to explain confidently in a short appointment, and it is a core focus of continuing professional development in nutrition. The College of Contemporary Health’s Nutrition & Weight Management Essentials CPD short course is designed for practitioners who want to strengthen their grounding in evidence-based nutrition and weight management before applying it in conversations with patients.

It is also worth keeping the study’s limits in view. This was a small trial of 42 people, conducted under closely controlled feeding conditions with weekly dietetic support and all food provided. Whether the ketogenic advantage persists in free-living conditions, over longer periods, and across broader populations remains to be established.

The research was supported by the National Institutes of Health and the Foundation for Barnes-Jewish Hospital.

CCH insight

Findings like these are only useful at the point where a clinician can translate them into a realistic, personalised plan with a patient. Nutrition & Weight Management Essentials is a CPD-accredited short course from The College of Contemporary Health, developed for healthcare professionals who want a practical, evidence-informed foundation in nutrition and weight management.

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Higher Coffee Intake Linked to Lower Visceral Fat and Greater Muscle Mass

Key Takeaways: 

• Higher habitual coffee intake was associated with lower total and visceral fat and greater skeletal muscle mass, despite a similar BMI.
  
• Coffee intake was linked to lower branched-chain amino acids in both sexes, and to sex-specific differences in testosterone and SHBG.
  
• The study was observational, so it cannot show that drinking coffee caused any of the differences identified. 
  
  
  

A familiar drink with poorly understood biology

Coffee is consumed around the world every day, and earlier research has associated coffee drinking with a reduced risk of conditions including type 2 diabetes and cardiovascular disease. What has remained unclear is why. Scientists still do not fully understand the biological processes that might explain those connections, which has made it difficult to interpret the epidemiological signal.

New research from Finland now suggests that regular coffee consumption is associated with healthier body composition, favourable metabolic markers, and distinct patterns involving sex hormones in men and women.

What the researchers examined

Researchers at the University of Oulu analysed information from 2,264 people who were 46 years old and taking part in the Northern Finland Birth Cohort 1966. The team investigated how participants’ usual coffee intake related to circulating metabolites, indicators of cardiometabolic risk, and sex hormone levels.

Studying a single birth cohort at a single age has a particular advantage: it removes age itself as a source of variation, allowing differences between people with higher and lower coffee intake to stand out more clearly.

Lower body fat and greater muscle mass

People who consumed more coffee tended to have lower levels of both total body fat and visceral fat, along with greater skeletal muscle mass.

Notably, these differences appeared even though participants with higher and lower coffee intake had a similar body mass index (BMI). That detail matters clinically. BMI cannot distinguish fat mass from lean mass, or subcutaneous fat from the visceral fat that sits around the abdominal organs and carries the stronger association with cardiometabolic risk. Two people with an identical BMI may therefore have meaningfully different metabolic profiles, and in this cohort coffee intake tracked with that hidden difference rather than with weight itself.

A metabolic marker associated with diabetes risk

Higher coffee consumption was also associated with lower circulating concentrations of branched-chain amino acids in both men and women. When chronically elevated, these biomarkers have previously been associated with insulin resistance and a greater risk of developing type 2 diabetes.

This finding sits alongside the body composition results rather than separately from them, since visceral fat and insulin resistance are themselves closely linked.

Different hormonal patterns in men and women

Some of the clearest differences appeared among men. Greater coffee consumption was associated with a more favourable glucose-insulin profile, higher levels of total and bioavailable testosterone, and greater concentrations of sex hormone-binding globulin (SHBG). However, free testosterone and the free androgen index were modestly lower.

The hormonal associations were less extensive in women. Higher coffee consumption was mainly associated with increased SHBG and lower measures of free androgens.

The common thread across both groups was SHBG, the carrier protein that binds circulating sex hormones and influences how much is biologically available to tissues. Higher SHBG has itself been studied in relation to metabolic health, which makes it a plausible point of connection between the hormonal and cardiometabolic findings.

“Coffee is consumed by millions of people every day, yet we still know surprisingly little about how it relates to our metabolism and hormones. What stood out in our findings was a distinct hormonal signature that didn’t disappear even after we took into account BMI and lifestyle factors, with several of these associations differing between men and women,” says Luca Verroest, lead author of the study and Doctoral Researcher at the University of Oulu.

Why the hormonal findings could matter

The findings raise the possibility that hormonal pathways could help explain some of the previously observed relationship between coffee consumption and metabolic health.

Because the research was observational, however, it cannot establish that drinking coffee directly caused any of the biological differences identified in the study. People who drink more coffee may differ from those who drink less in ways the analysis could not fully capture, and the direction of any relationship cannot be determined from data collected at a single point in time.

For clinicians, the more immediately useful message concerns interpretation rather than advice. Findings of this kind reinforce how much a single anthropometric measure can conceal, and how dietary patterns, body composition, and endocrine markers interact when assessing cardiometabolic risk. Practitioners who want to strengthen that interpretive skill set often look to structured CPD such as the College of Contemporary Health’s Nutrition & Weight Management Essentials short course, which examines how dietary intake relates to body composition and metabolic health in everyday practice.

Finland as a study setting

The setting also makes the research especially relevant. Finland ranks among the world’s highest coffee-consuming countries, with average annual consumption of approximately 11.8 kilograms (26 pounds) per person. A population with high and widely varying intake offers greater statistical range than one in which most people drink little coffee at all.

What happens next

Researchers say the results offer a starting point for studies designed to determine whether coffee itself produces these biological changes and, if so, which compounds may be responsible. Scientists are currently investigating these questions using animal models, with the longer-term aim of moving towards human intervention studies.

Additional research will be necessary before the findings can be used to shape dietary recommendations. For now, the study contributes a mechanistic hypothesis rather than a change in practice.

The study, “Associations of habitual coffee intake with testosterone and cardiometabolic markers: the Northern Finland Birth Cohort 1966 study,” was published in the European Journal of Nutrition.

CCH insight

Body composition, dietary patterns, and metabolic markers rarely tell a complete story in isolation, and BMI alone can mask clinically important differences. The College of Contemporary Health’s Nutrition & Weight Management Essentials short course helps healthcare professionals interpret these measures together and apply nutritional evidence confidently in patient-facing practice.

Explore Nutrition & Weight Management Essentials → 

Source: University of Oulu, Finland

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AI Calorie Tracking Apps: Convenient, Popular and Consistently Inaccurate

Key Takeaways: 

• Four popular photo-based calorie apps underestimated meal energy by 250 to 345 calories and fat by around 30 grams – roughly a third in both cases.
  
• Accuracy varied: higher-calorie meals fared better than lower-calorie ones, and carbohydrates were estimated more consistently than other macronutrients.
  
• Ketogenic meals proved hardest to assess, because their high fat content is consistently underestimated.
  
  
  

Convenience that comes with a margin of error

Advances in artificial intelligence have changed how many people record what they eat. Rather than weighing ingredients or searching a database entry by entry, a person can now photograph a plate of food and let an app estimate its nutritional content in seconds. The convenience is obvious. The accuracy, according to new research, is rather less reliable.

A study conducted at the National Institutes of Health (NIH) Clinical Center compared four popular photo-based apps against meals prepared under tightly controlled laboratory conditions. All four underestimated both calories and fat by approximately a third.

How photo-based calorie tracking works

Photo-based calorie tracking uses AI image recognition to identify the foods present in a photograph of a meal and to estimate the portion sizes on the plate. Those identifications and estimates are then matched against nutrition databases, which the app uses to calculate the energy and macronutrient content of the meal.

The appeal for people managing their weight or monitoring their intake for other health reasons is that the process removes several steps of manual data entry. The trade-off is that the app is making two judgements at once – what the food is, and how much of it there is – before any nutritional calculation begins.

“Photo-based calorie tracking apps are very popular, especially for people trying to manage their health or lose weight,” said Aaron Hengist, a postdoctoral visiting fellow with the Intramural Program of the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), part of the National Institutes of Health. “However, the accuracy of many of these apps has not been thoroughly evaluated. Our study helps address this question by looking at whether these apps can reliably estimate calories.”

A metabolic kitchen as the reference standard

The research forms part of a larger diet study at the NIH Clinical Center examining how the body processes nutrients when a person follows either a low-carbohydrate (ketogenic) diet or a standard diet.

Meals for that clinical trial are prepared in a controlled metabolic kitchen – a research kitchen in which every ingredient is weighed to the nearest 0.1 gram. That level of precision gave the investigators something unusual: a set of real, plated meals whose exact nutritional composition was already known.

The researchers took standardised photographs of 102 meals prepared for the diet study and ran the images through four apps: MyFitnessPal, LoseIt!, CalAI and Appediet.

“By using meals prepared in a tightly controlled metabolic kitchen, we were able to compare the apps’ estimates against a precise reference,” said Hengist. “This kind of direct, high-quality comparison hasn’t been available before.”

What the analysis found

Across the 102 meals, all four apps underestimated energy content by approximately 250 to 345 calories on average. Fat was underestimated by around 30 grams. In percentage terms, both calories and fat came in roughly a third below the true values recorded in the metabolic kitchen.

For a person using an app to guide daily intake, an error of this size is not trivial. A consistent shortfall of 250 to 345 calories per meal, repeated across a day, would produce a substantially inaccurate picture of overall energy intake – and would do so in the direction least helpful to someone trying to reduce it.

Where the apps performed better

The findings were not uniformly negative. The analysis showed that MyFitnessPal and LoseIt! estimated the energy content of higher-calorie meals more accurately than lower-calorie meals. All four apps also estimated carbohydrates more consistently than the other macronutrients, suggesting that carbohydrate-containing foods may be easier for image recognition systems to identify and quantify than fats in particular.

Hengist was direct about the practical implication for people using these tools without adjusting the app’s output.

“People using a photo-based tracking app without adjusting the portions or entering the amounts of food should take the results with a grain of salt,” said Hengist. “These apps tend to underestimate calories, especially from fats, so what they actually ate is likely higher than what the app shows.”

Ketogenic meals pose a particular challenge

After completing the initial analysis, the researchers extended the work to more than 200 additional meals in order to understand what factors influence app accuracy.

Their early results suggest that the apps struggle more with meals forming part of a low-carbohydrate ketogenic diet. The likely explanation is straightforward: these meals derive a large proportion of their energy from fat, and fat is precisely the macronutrient the apps most consistently underestimate.

This has implications for anyone supporting people who follow ketogenic or other high-fat dietary patterns, whether for weight management, metabolic health or the management of specific conditions. The tracking tool a person is relying on may be least accurate in exactly the dietary context where fat intake matters most.

For healthcare professionals who regularly review food diaries or app exports during weight management consultations, findings of this kind reinforce the value of structured training in dietary assessment. The College of Contemporary Health’s CPD-accredited Nutrition and Weight Management Essentials short course covers how dietary intake is assessed in practice, the limitations of self-reported data, and how to have constructive conversations with people about what and how much they are eating.

Improving accuracy in the real world

The investigators do not conclude that photo-based tracking should be abandoned. Their view is that combining photo-based features with more traditional methods of measuring diet quality could improve the real-world accuracy of calorie-tracking apps. In practical terms, that means treating the photograph as a starting point rather than a finished record – confirming what the app has identified, adjusting portion sizes, and entering quantities where they are known.

Olivia Charles, a postbaccalaureate intramural research training fellow at NIDDK, will present the findings at NUTRITION 2026, the flagship annual meeting of the American Society for Nutrition, held 25–28 July in National Harbor, Maryland, just outside Washington, D.C. As with research presented at scientific meetings generally, the results should be regarded as preliminary until they appear in a peer-reviewed publication.

For people using these apps day to day, the practical message is a modest one. A photograph is a useful prompt and a low-friction way to build a habit of recording intake. It is not, on the current evidence, a measurement.

CCH insight

Digital tools are increasingly part of how people monitor their diet, but their outputs need to be interpreted rather than accepted at face value – particularly where fat intake or high-fat dietary patterns are involved.

The College of Contemporary Health’s Nutrition and Weight Management Essentials CPD short course equips healthcare professionals with a working understanding of dietary assessment, macronutrient composition and evidence-based weight management, including how to interpret self-reported and app-generated intake data in clinical conversations.

Explore Nutrition and Weight Management Essentials 

Source: EurekAlert!

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Daily Tomato Intake May Lower Liver Fat in People With MASLD, New Study Suggests

Key Takeaways: 

• In a six-week randomised study of 79 adults with metabolic dysfunction-associated liver disease (MASLD), people who ate 200 grams of raw tomatoes and 50 grams of tomato sauce each day showed a greater reduction in hepatic steatosis than people following a tomato-free control diet.
  
• Liver fat fell in both groups, and researchers found no meaningful differences between the groups in liver stiffness, liver enzymes, lipids or body mass index after the intervention period.
  
• Independent specialists described the findings as exploratory rather than practice-changing, noting the short duration, the narrow participant profile and the absence of improvement in clinically relevant markers.
  
  
  

What the research set out to examine

Metabolic dysfunction-associated liver disease (MASLD) covers a spectrum of liver problems, but its defining feature is hepatic steatosis – the accumulation of fat within the liver. A diagnosis also requires the presence of at least one cardiometabolic risk factor, such as obesity or high blood pressure.

Diet and lifestyle changes are a mainstay of support for people living with MASLD, and researchers are increasingly interested in whether particular foods offer measurable advantages over others. A study published in Nutrients set out to test one such food: the tomato, a staple of the Mediterranean diet.

The research team wanted to establish whether regular tomato consumption would influence liver steatosis in people who already had a MASLD diagnosis.

How the study was designed

The study enrolled 79 adults with MASLD. Researchers applied a number of exclusion criteria, ruling out people who consumed above a set threshold of alcohol and those with a body mass index above 30, the point at which obesity is classified.

Participants were divided into two groups. One group followed a tomato-free control diet. The other consumed 200 grams of raw tomatoes and 50 grams of tomato sauce daily. All tomato products were supplied by the same producer to keep the intervention consistent, and participants were asked to carry on with their usual lifestyle in every other respect.

The intervention ran for six weeks. Across that period, researchers tracked a range of health indicators, including body composition, hepatic steatosis, liver stiffness and cholesterol levels.

What the researchers found

Hepatic steatosis declined in both groups over the six weeks. The decrease was greater, however, among people in the tomato group.

Further analysis showed that hepatic steatosis had been broadly similar between the two groups at baseline, which strengthens the comparison. Other measures told a quieter story. Researchers identified no major changes in liver stiffness, and no significant differences between the groups in lipids, liver enzymes or body mass index at the end of the six-week period.

Summarising the result, the authors suggested that “tomato consumption may reduce hepatic fat accumulation independently of major changes in body weight, total and abdominal adiposity.”

Because liver fat shifted while weight and body composition did not, the study raises a familiar practical question for clinicians: how far can dietary composition alone move metabolic outcomes when overall energy intake stays broadly the same? It is the kind of question CCH explores in its CPD short course Nutrition & Weight Management Essentials, which examines the relationship between modern nutrition and weight, and how evidence-based dietary advice translates into everyday clinical conversations.

Study limitations and continued research

The six-week window is short, so the study cannot speak to whether any benefit persists over the longer term. The research also recruited only adults aged 65 and under, leaving it unclear how the findings might apply to older adults.

Most participants were men, so more balanced recruitment would strengthen future work. The decision to exclude people with a body mass index above 30 also narrows how widely the results can be applied.

Endocrinologist and obesity specialist Randa Abdelmasih MD, DipABOM, from the University of Texas Medical Branch (UTMB), who was not involved in this study, told Medical News Today:

“The study demonstrates a modest reduction in hepatic steatosis over only six weeks in a highly selected population of adults with MASLD and BMI [body mass index] of 30 kg/m² [kilograms per square meter] or more. Most patients we see in clinical practice have obesity (BMI over 30 kg/m²), type 2 diabetes, or more advanced metabolic disease, so the generalizability of these findings is limited.”

Jonathan Jennings, MS, MD, a board-certified internist with Medical Offices of Manhattan, who was likewise not involved in the research, raised a related concern about how participants were selected.

“The inclusion criteria required only one cardiometabolic risk factor, and it could be any risk factor. I am concerned that not all risks are equal, and people with multiple factors are at higher risk than those with a single risk factor,” Jennings said.

“Type 2 diabetes is more likely to lead to MASLD than high blood pressure but the study evaluates them as equal risk factors,” he pointed out.

The researchers themselves note that the reduction in liver fat may have been influenced by other factors, including the effect that taking part in a dietary intervention study can have on participants’ behaviour. The team was also reliant on dietary counselling and on participants’ own reports of how closely they followed the intervention.

Abdelmasih added that because the intervention combined raw tomatoes with tomato sauce, it is “difficult to determine which component or combination was responsible for the observed effect.”

A further gap is that researchers did not measure circulating levels of lycopene and carotenoids, the compounds most often proposed as the mechanism behind any effect tomatoes might have on liver health.

Limited clinical application at this stage

The authors describe their study as exploratory, intended primarily to inform future research. They call for confirmation through larger and longer studies, and encourage readers to treat the findings as hypothesis-generating rather than conclusive.

The clinical value is also uncertain because so much else stayed the same. As Abdelmasih put it:

“The study showed improvement in liver fat but no significant improvements in liver stiffness, fibrosis scores, liver enzymes, insulin resistance, inflammatory markers, lipid profile, or body composition. Therefore, while the imaging findings are interesting, we cannot conclude that tomato consumption meaningfully alters disease progression or improves clinically relevant outcomes.”

What this means for people living with MASLD

Within its limits, the study does point to a possible benefit of tomato consumption for people with MASLD, and to a low-cost dietary strategy that may help with fat accumulation in the liver.

Tomatoes may carry other advantages too, with existing research pointing towards cardiovascular benefits and potential anti-cancer properties.

Even so, the sensible route is for people to work with their doctor and wider healthcare team on a dietary plan that addresses their overall health, rather than concentrating on any single food.

Jennings underlined that point, and flagged two practical cautions:

“The study’s conclusions are hopeful but careful discussion with a healthcare provider is still needed before engaging in any radical dietary adjustments. Tomatoes and tomato-based products may be problematic for individuals with gastroesophageal reflux disease (GERD). Many tomato-based foods are also calorically dense and may worsen insulin resistance in certain individuals.”

The broader treatment context matters as well. According to Abdelmasih: “Dietary interventions should be viewed within the broader context of treating the underlying metabolic disease. For patients with obesity, sustained weight loss of approximately 10% or more remains the intervention with the strongest evidence for improving steatohepatitis and fibrosis.”

“While tomatoes can certainly be part of a healthy Mediterranean diet, they should not distract from therapies that have demonstrated meaningful improvements in liver and cardiometabolic outcomes,” she concluded.

CCH insight

Conversations about diet sit at the centre of metabolic and liver care, and single-food headlines can make those conversations harder rather than easier. CCH’s CPD short course Nutrition & Weight Management Essentials gives healthcare professionals a grounding in the fundamentals of nutrition, the factors driving weight gain, and what effective weight management looks like in practice – so you can place findings like these in proportion for the people you support.

Explore Nutrition & Weight Management Essentials →

Expert commentary in this article was provided to Medical News Today. Read the original report here.

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One Avocado a Day May Lower a Hidden Heart Disease Risk in Adults Living With Obesity

Key Takeaways:

• Adults living with obesity who ate one avocado a day for six months showed a fall of 49 nanomoles per litre in LDL particle concentration – equivalent to roughly a 4% reduction in heart disease risk.
  
• LDL particle number is a risk factor distinct from LDL cholesterol itself, and it tends to be higher in people with abdominal obesity, meaning two people with identical cholesterol readings can carry very different levels of risk.
  
• The benefit appeared consistently across sex, race, ethnicity, age and body mass index, suggesting that a single, sustainable dietary addition can shift a meaningful cardiometabolic marker without any wider change to diet or activity.
  
  
  

A single dietary change, made in the real world

Adding one avocado to the daily diet may reduce heart disease risk in adults living with obesity, according to research led by the Penn State Department of Nutritional Sciences and published in the Journal of Clinical Lipidology.

The team found that regular avocado consumption was associated with a lower concentration of low-density lipoprotein (LDL) particles – the protein particles that transport cholesterol around the body – in the blood. That reduction corresponded to an approximate 4% decrease in heart disease risk.

What distinguishes the finding is its modesty. Rather than testing a wholesale dietary overhaul, the researchers examined what happens when people make one addition and otherwise carry on as normal.

“If people want to improve the quality of their diet, making one small change might be a more feasible strategy than attempting to change their entire diet,” said Janhavi Damani, postdoctoral scholar at Penn State and first author of the study. “For people with obesity, including avocados in their daily diet might be a good starting place.”

Why particle number matters, not just cholesterol

LDL particles represent a risk factor for heart disease that is separate from LDL cholesterol – the so-called “bad cholesterol” that is itself a significant contributor to risk. The risk posed by LDL particles is typically higher in people with abdominal obesity, the researchers noted.

The distinction rests on a point of basic physiology that standard lipid panels do not capture. LDL cholesterol cannot travel through the body unaided; it must be carried by a protein particle. When a greater number of protein particles are involved in transporting the same quantity of cholesterol, heart disease risk rises – even though the measured cholesterol figure is unchanged.

Damani illustrated the point directly.

“Imagine two people with the same high levels of LDL cholesterol,” Damani said. “Person A carries their cholesterol in fewer, larger LDL particles, and Person B carries their cholesterol in more, smaller LDL particles. Person B’s heart disease risk would be higher because their overall particle count is higher even though a test of their LDL cholesterol would look identical.”

How smaller particles do more damage

Those smaller particles penetrate artery walls more easily and contribute to the accumulation known as plaque, Damani explained.

Plaque raises heart disease risk through two mechanisms working together. It narrows the space available for blood to pass through a vessel, and it reduces the vessel’s flexibility. The consequence becomes clearest under load: when a person’s heart is working hardest – through exertion, heat, stress or any other cause – their blood pressure rises more sharply than it otherwise would, because the vessel can no longer expand to accommodate the increased demand. That failure to compensate can be enough to trigger a cardiac event such as a heart attack.

This mechanistic detail matters clinically, because it explains why particle count can carry prognostic weight even when a patient’s cholesterol result looks reassuring. Practitioners working in weight management and cardiometabolic care increasingly need to interpret markers of this kind alongside anthropometric measures, and this is territory that CCH’s CPD short course provision in obesity care covers in some depth.

Inside the Habitual Diet and Avocado Trial

For this analysis, the researchers drew on data originally collected from 786 participants in the Habitual Diet and Avocado Trial, a six-month study of adults aged 25 years and older.

Eligibility was defined by waist circumference. Men qualified if their waist circumference exceeded 102 centimetres (40 inches); women qualified if theirs exceeded 89 centimetres (35 inches).

Participants were divided into two groups. Half were instructed to maintain their usual diet and activity levels. The other half were provided with one avocado to consume each day and were also instructed to maintain their usual diet and activity levels. No other dietary guidance or restriction was applied.

The original Habitual Diet and Avocado Trial had already established that adding avocado to the diets of people living with obesity did not alter weight or waist circumference, but could reduce levels of LDL cholesterol.

What the blood samples showed

In the current study, the researchers compared blood samples collected at the start and at the end of the six-month period.

Across the study, LDL particle levels in the avocado-per-day group fell by 49 nanomoles per litre. That change corresponded to an approximate 4% reduction in heart disease risk, according to the researchers.

The team was careful to set this figure in proportion.

“Four percent is a modest reduction compared with the 14% to 29% lower heart disease risk associated with improving the overall diet,” Damani said. “However, it is a step in the right direction.”

A consistent effect across the study population

One of the more notable findings concerned who benefited. Regardless of participants’ sex, race, ethnicity, age or body mass index, they were equally likely to experience improvements in LDL particle levels.

The researchers took this to indicate that anyone living with obesity could benefit from avocado consumption. They added a clear caveat, however: people should speak to a registered dietitian nutritionist or their physician for personalised, expert guidance on improving their diets.

From controlled conditions to unpredictable lives

The study’s most significant contribution may lie less in the size of the effect than in the setting in which it was demonstrated.

“Penn State researchers demonstrated several years ago that avocado consumption could reduce LDL cholesterol and levels of LDL particles,” said Kristina Petersen, associate professor of nutritional sciences and senior author of this study. “But in that study, the researchers controlled participants’ entire diets throughout the experiment. This study demonstrated benefits in the real world, where people’s diets are much less predictable. In the course of people’s normal lives, avocado consumption still contributes to a healthier diet.”

That shift – from a tightly controlled feeding study to free-living participants managing their own meals – is what makes the result relevant to everyday practice. A 4% reduction achieved under laboratory conditions tells clinicians relatively little about what patients will actually sustain. A comparable reduction achieved by people eating as they normally do, with one addition, is a different kind of evidence.

What this means for practice

For healthcare professionals supporting people living with obesity, the findings reinforce a familiar principle with fresh quantitative backing: incremental, achievable changes can move clinically meaningful markers. They also underline the value of looking beyond standard lipid measurements when assessing cardiovascular risk in patients with abdominal obesity, where LDL particle number may reveal risk that a conventional cholesterol result conceals.

None of this positions a single food as a substitute for comprehensive care. The researchers’ own framing is deliberately measured – a step in the right direction, not a solution. But in a field where adherence often determines outcomes more than the theoretical strength of an intervention, feasibility is itself a clinical variable worth taking seriously.

CCH insight

It is always re-assuring to hear about studies which show clear benefits of foods we associate with good health, so this is great news for people who eat avocados regularly and a nice reminder for others to maybe eat them more often. However, high cholesterol and other risk factors for cardiometabolic diseases are most common in populations of high deprivation, who are unable to buy avocados regularly due partly to access but mainly due to cost.

This study’s practical value lies in feasibility – one addition, sustained over six months, moving a real marker of cardiovascular risk. Translating that kind of evidence into advice patients will actually follow is the core skill of nutritional care in obesity management. CCH’s Nutrition & Weight Management Essentials (6 hours, fully online, CPD-accredited) gives healthcare professionals a solid grounding in fundamental nutrition concepts, the factors driving weight gain, and evidence-based approaches to both weight loss and long-term maintenance, with real-life case studies throughout.

Explore Nutrition & Weight Management Essentials →

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Intermittent Fasting Maintains Long-Term Weight Loss Irrespective of Meal Timing, Study Shows

Key Takeaways: 

• Adults living with overweight or obesity who followed a 16:8 fasting pattern for 12 weeks kept off significantly more weight a full year after the intervention ended.
  
• The benefit held whether the eight-hour eating window fell early or late in the day, giving people the freedom to fit fasting around their own routines.
  
• One in three participants chose to carry on fasting unprompted during the follow-up year, pointing to a habit that is relatively easy to sustain.
  
  
  

A twelve-week habit with lasting results

New research has shown that confining daily food intake to an eight-hour window helps people living with overweight or obesity maintain their weight loss 12 months after a structured intervention comes to an end. The work was carried out by scientists from the University of Granada (UGR), the Granada Institute for Biomedical Research (ibs.GRANADA), the Public University of Navarra and the Biomedical Research Networking Center (CIBER), and was recently published in the journal Clinical Nutrition.

The trial followed 99 adults, half of them women, all of whom were living with overweight or obesity. It focused on intermittent fasting, and specifically the approach widely known as 16:8, in which people fast for 16 hours and eat only during the remaining eight. The findings indicate that this pattern is an effective way to hold on to weight loss over the medium term.

Crucially, the researchers found that the benefits endured a year later regardless of when the eating window fell. Whether participants ate early in the day, between 9 a.m. and 5 p.m. (early fasting), or later on, between 1 p.m. and 9 p.m. (late fasting), they fared better than people who kept to their usual routine of eating across a window of 12 hours or more. Both the early- and late-fasting groups sustained significantly greater weight loss at 12 months, and the early-fasting group also held on to a greater reduction in fat mass. According to the team, this suggests that the approach is not only feasible and effective in the short term but also produces effects that last.

Body composition assessed one year later

For the first 12 weeks, participants were split into four groups, each of which took part in a Mediterranean diet education programme. A control group kept its usual eating window of 12 hours or longer. An early-fasting group used an eight-hour window that began before 10 a.m., while a late-fasting group used an eight-hour window that started after 1 p.m. A fourth, self-selected group chose its own eight-hour window.

Weight, fat mass and fat-free mass were measured before and after the 12-week intervention, and again a year after the study finished. The work forms part of a larger project whose principal results appeared in the journal Nature Medicine. That analysis found that people who practised time-restricted eating (TRE), whatever their eating schedule, lost an average of 3–4 kilograms (6.6–8.8 pounds) more than those given nutritional advice alone.

Dr Alba Camacho Cardeñosa, a researcher at the University Joint Institute for Sport and Health (iMUDS) at the University of Granada and a postdoctoral fellow at ibs.GRANADA in the Endocrinology and Nutrition Department at San Cecilio University Clinical Hospital, is the study’s first author. She explains that “to date, although we knew that intermittent fasting promotes modest weight loss in the short term, it was unclear whether its effects were sustained over time. By evaluating the participants 12 months after the intervention ended, we demonstrated that the changes in body weight persist.”

The researchers also point to the strength of ongoing adherence, noting that “a very positive finding is that one in three people decided to continue practicing intermittent fasting on their own during that year of follow-up, suggesting that it is a relatively easy habit to integrate into daily life.”

A flexible strategy against obesity

The study was led by researchers from ibs.GRANADA belonging to the PROFITH CTS-977 research group at the University of Granada, headed by Professor Jonatan Ruiz Ruiz. It was conducted in collaboration with the San Cecilio University Clinical Hospital and the Virgen de las Nieves University Hospital in Granada, the Public University of Navarra, the CIBER on Obesity (CIBEROBN) and the CIBER on Frailty and Healthy Aging (CIBERFES).

The team emphasises that as little as 12 weeks of intermittent fasting may serve as an effective medium-term strategy for weight management in adults living with overweight or obesity. Because both early- and late-day regimens proved effective, the findings give people the flexibility to choose the schedule that best fits their lifestyle, which may in turn improve adherence and support more successful obesity treatment.

CCH insights:

These are very encouraging results for the use of time-restricted eating (TRE) as a strategy for weight loss maintenance. It would be good to now see research into the use of TRE as a tool to prevent weight regain after cessation of GLP-1 therapy. If TRE is adopted during GLP-1RA treatment, and continued after stopping the medication, could it help maintain weight loss and cardiometabolic gains?

Helping patients hold on to their gains — during treatment and in the months after it ends — is exactly the terrain of our two-hour CPD course GLP-1RAs in Practice: Supporting Patients During Treatment, which covers nutrition, monitoring and preparing patients for life after treatment for any clinician managing the full arc of GLP-1RA care.

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AI Finds Simple Food Swaps That Make Meals Healthier and Cheaper

Key Takeaways:

• A new artificial intelligence framework can identify just one to three ingredient swaps that make a meal meaningfully more nutritious and noticeably less expensive, without overhauling it entirely.
  
• In testing, AI-generated meals sat 47% closer to United States Department of Agriculture (USDA) nutritional targets than the real meals they were modelled on, while staying close to people’s actual eating habits in type and flavour.
  
• Applying one to three swaps lifted nutritional quality by roughly 10% and cut modelled meal costs by 19 to 32%, most often by adding vegetables or legumes and removing high-sodium or processed items.
  
  
  

Turning nutrition science into practical meals

A new artificial intelligence framework that recommends as few as one to three ingredient swaps can make everyday meals meaningfully more nutritious and less expensive. That is the central finding of a study published on 28 May in the open-access journal PLOS Digital Health by PhD student Trevor Chan and Professor of Computer Science Ilias Tagkopoulos of the University of California, Davis.

The challenge the researchers set out to tackle is a familiar one. The dietary guidelines that help reduce people’s risk of conditions such as diabetes and cardiovascular disease are well established, yet turning that nutrition science into day-to-day meals remains difficult for most people. Many existing diet recommendation tools ask people to change too much all at once, which can lead to practices that are hard to sustain or leave people unsure how to put the advice into action.

How the study worked

To build their framework, the researchers drew on data from the What We Eat in America study, analysing 135,491 meals logged by 55,228 adults. From this, they identified common meal patterns across breakfast, lunch and dinner.

They then trained a generative AI model to create realistic meals that followed those patterns, while also adjusting serving sizes. Crucially, the team tested whether the model could pinpoint one, two or three ingredient swaps within each meal that would further improve both its nutritional value and its cost.

What the AI achieved

The results were striking. Compared with real meals in the same dietary pattern, the AI-generated meals were 47% closer to USDA nutritional targets, while remaining close in overall meal type and flavour to what people actually eat.

When ingredient substitutions were applied, swapping just one to three foods improved nutritional quality by approximately 10%, while reducing modelled meal costs by between 19 and 32%. The most common substitutions the system identified involved adding vegetables or legumes, and swapping out high-sodium or processed items.

Improving eating habits

The trained model also outperformed an unspecialised model. Set against GPT-4o, the purpose-built system produced meals that came closer to USDA guidelines on macronutrients.

The authors are careful to note the limits of the work. The evaluation is entirely computational and has not yet been tested with real users. Even so, they suggest the approach could help people find simple ways to improve their eating habits.

As the authors write: “By turning dietary guidelines into realistic, budget-aware meals and simple swaps, this framework can support public-health programs and consumer apps.”

Chan and Tagkopoulos summarise the thinking behind the study: “Dietary guidelines often tell people what a healthy diet should look like, but they do not always show how to get there from the meals people already eat. Our study shows that it is possible to translate dietary standards into practical meal-level changes by identifying a small number of ingredient substitutions that can make meals healthier and cost-effective, while keeping them recognizable…[w]hat we found most interesting is that improving meals does not necessarily require a complete redesign. In many cases, targeted substitutions may be enough to move a meal closer to dietary recommendations, which could make healthy eating feel more practical and achievable.”

They add: “Healthier eating does not have to mean giving up the meals people already enjoy. With AI, we can identify small ingredient substitutions that preserve taste, while are better for our health and our pocket.”

Funding

The work was supported by grants from the U.S. Department of Agriculture and the National Science Foundation.

Source: UC Davis College of Engineering

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Four Weeks of Tomato-Soy Juice Lowered Inflammation in Adults with Obesity

Key Takeaways:

• In a four-week study, a tomato-soy juice rich in lycopene and soy isoflavones significantly reduced three blood markers of systemic inflammation in healthy adults with obesity, while a control tomato juice lacking those compounds did not.
  
• The researchers chose a low-carotenoid tomato juice as the comparison drink, rather than water, so they could isolate the effects of the lycopene and isoflavones rather than the effects of tomato juice in general.
  
• Building on these results and supporting animal data, the team has secured federal funding for a pilot clinical trial examining whether the same juice can ease inflammation in people living with pancreatitis.
  
  
  

A food-based approach to inflammation

Drinking a tomato-soy juice packed with plant compounds previously shown in animal studies to support health lowered pro-inflammatory proteins in healthy adults with obesity after four weeks, according to a new study. The researchers say the findings point to the juice’s potential as a functional food that could help rein in the persistent, unchecked inflammation that underpins a wide range of chronic conditions.

The juice was formulated to deliver high levels of two plant-based compounds, lycopene and soy isoflavones, both of which earlier research suggests have antioxidant and anti-inflammatory properties. Measured against a control tomato juice that lacked these compounds, the tomato-soy juice produced a significant drop in the blood levels of three proteins that serve as markers of systemic inflammation.

“The idea is, can we use food-based interventions to modulate inflammation?” said lead author Jessica Cooperstone, associate professor of horticulture and crop science at The Ohio State University. “And can we test this in a rigorous way so that we can really see this is affecting inflammation, versus just saying something is anti-inflammatory?”

The study was published recently in the journal Molecular Nutrition & Food Research.

What is in the juice

Lycopene is a carotenoid, the class of pigments responsible for the colours of tomatoes and various other vegetables. Soy isoflavones are flavonoids that mimic the action of the hormone oestrogen. Both are phytochemicals, naturally occurring compounds that help plants thrive.

Years ago, drawing on studies that linked diets rich in either tomato products or soy with a reduced risk of prostate cancer, Ohio State researchers developed the tomato-soy juice. It was made using tomatoes bred to contain a high concentration of lycopene – varieties also developed and grown at Ohio State – and then enriched with a soy isoflavone extract.

Subsequent research at the university connected a higher intake of the tomato-soy juice with reduced prostate-specific antigen levels in some men with prostate cancer. Studies conducted elsewhere have likewise suggested that tomatoes and soy, whether eaten separately or together, can influence inflammatory and metabolic pathways tied to obesity and other chronic illnesses.

“There’s been enough compelling evidence that compounds from tomatoes and soy might be modulating inflammation that we decided to test this in people,” Cooperstone said.

How the study was carried out

For the new study, 12 healthy adults with obesity drank two 6-ounce cans of the tomato-soy juice every day for four weeks. Following a washout period, the same participants then consumed the low-carotenoid control tomato juice for a further four weeks.

The choice of comparison drink was deliberate. Rather than pitting the juice against plain water, the team selected a tomato juice stripped of the key compounds so that any difference could be attributed to those compounds specifically.

“The hypothesis is that it’s the lycopene from the tomatoes and the isoflavones from the soy that’s inducing the effect, so we didn’t want to have a control that’s just water,” Cooperstone said.

What the blood tests showed

Before and after each four-week period, the researchers collected blood samples and tested them for cytokines, the pro-inflammatory proteins produced by the immune system. Only the tomato-soy juice produced significant reductions, and it did so in three cytokines: interleukin (IL)-5, IL-12p70 and granulocyte-macrophage colony-stimulating factor (GM-CSF). The juice was also associated with a downward trend in tumour necrosis factor alpha (TNF-a), although that particular change did not reach statistical significance.

Clues from the urine analysis

The team also examined participants’ urine before and after each trial period, looking for changes in metabolites. Metabolites are the molecular products of the biochemical reactions that break down nutrients to generate energy and carry out other essential functions in the body.

The analysis revealed that both the tomato-soy juice and the control tomato juice prompted some of the same shifts in metabolite profiles, indicating that certain tomato-driven effects occurred even in the absence of lycopene. Among the changes specifically induced by the tomato-soy juice, shifts in soy isoflavone metabolites stood out. The researchers note that, while more investigation is warranted, these changes offer further evidence that the food-based intervention is acting on human biology.

“This is probably a function of the fact that there’s more to our intervention agents than just these two compounds,” Cooperstone said. “Ultimately, we want to have a better understanding of how the foods that we eat are relating to our health. And when we really want to be sure, we need to test them in clinical trials. And that’s what we’re doing here.”

Next steps: a pancreatitis trial

On the strength of these results and additional data, Cooperstone and her colleagues have received funding from the National Institute of Diabetes and Digestive and Kidney Diseases for a pilot clinical trial. That trial will test whether consuming the same tomato-soy juice reduces inflammation in people living with pancreatitis.

The team has also gathered evidence from an animal model suggesting that the tomato-soy juice can lessen both inflammation and the severity of chronic pancreatitis. Those findings support the central prediction behind the new clinical trial, namely that the intervention could improve outcomes for people with the condition.

“Care for patients with pancreatitis is palliative, focused on controlling pain and GI symptoms. Our hypothesis is that the tomato-soy juice may serve as an intervention to decrease inflammation and hopefully increase patients’ quality of life,” Cooperstone said.

Funding and contributors

The work was supported by the U.S. Department of Agriculture, the National Institutes of Health, the Lisa and Dan Wampler Endowed Fellowship for Foods and Health Research, and the Foods for Health Initiative at Ohio State.

Co-authors include first author Maria Sholola, along with Jenna Miller, Emma Bilbrey, David Francis and Thomas Mace, all of Ohio State, and Janet Navotny of the USDA. Mace is the lead principal investigator on the pancreatitis trial. Cooperstone, Philip Hart and Kristen Roberts of Ohio State are also principal investigators on that trial.

Source: Eureka Alert!

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Carbohydrate-Rich Diets May Promote Weight Gain Even Without Higher Calorie Intake

Key Takeaways: 

• A new mouse study found that carbohydrate-rich foods such as bread, wheat flour, and rice flour promoted weight gain and fat accumulation even when total calorie intake did not significantly increase.
  
• Researchers observed that the weight gain appeared to be linked more closely to reduced energy expenditure and metabolic changes than to overeating.
  
• Scientists say future human studies will explore how factors such as whole grains, fibre content, food processing, meal timing, and combinations with protein and fat influence metabolic responses to carbohydrates.
  
  
  

Bread and carbohydrates under renewed scrutiny

Bread has served as a central part of human diets for centuries and remains a staple food in many cultures around the world. Foods such as bread, rice, noodles, and other carbohydrate-rich staples continue to form the foundation of everyday meals for billions of people.

However, as rates of overweight and obesity continue to increase globally, researchers are re-examining how modern dietary patterns may influence body weight and metabolic health. While high-fat diets have traditionally received much of the attention in obesity research, scientists are now taking a closer look at the role carbohydrates may play in weight regulation.

A new study led by researchers at Osaka Metropolitan University suggests that certain carbohydrate-heavy eating patterns may contribute to weight gain in ways that are not solely explained by consuming more calories.

The findings were published in Molecular Nutrition & Food Research. 

Obesity research has traditionally focused on fat intake

Obesity is associated with a broad range of chronic conditions and lifestyle-related diseases, including type 2 diabetes, cardiovascular disease, and metabolic dysfunction. Because of this, understanding the drivers of weight gain has become an increasingly important area of scientific research.

Historically, many obesity studies have focused primarily on dietary fat as the main contributor to excess weight gain. This is reflected in the widespread use of high-fat diets in animal research investigating obesity and metabolism.

At the same time, carbohydrate-rich foods remain deeply embedded in daily diets across the world. Despite their prominence, the metabolic effects of staple carbohydrates such as bread, rice, and noodles have not always been explored in the same depth.

Public perceptions around carbohydrates also remain widespread. Beliefs such as “bread makes you gain weight” or “carbohydrates should be restricted” are common, yet researchers say it has remained unclear whether such effects are driven by the foods themselves, overall dietary habits, eating behaviour, or broader metabolic responses.

Researchers investigated how carbohydrate-rich foods affect metabolism

To better understand the relationship between carbohydrates and weight gain, researchers led by Professor Shigenobu Matsumura at Osaka Metropolitan University’s Graduate School of Human Life and Ecology conducted a series of experiments in mice.

The study examined whether mice would preferentially select carbohydrate-rich foods over standard laboratory chow and how those dietary choices would affect body weight, metabolism, and energy expenditure.

The mice were separated into several dietary groups, including:

• Chow
• Chow + Bread
• Chow + Wheat Flour
• Chow + Rice Flour
• High-fat diet (HFD) + Chow
• High-fat diet (HFD) + Wheat Flour

Researchers monitored multiple metabolic indicators throughout the study, including:

• Body weight
• Fat mass
• Energy expenditure
• Blood metabolites
• Liver gene activity
  
  
  

Mice preferred carbohydrate-rich foods

The researchers found that mice consistently showed a strong preference for carbohydrate-rich foods. Animals given access to bread, wheat flour, or rice flour largely abandoned their standard chow diet in favour of these carbohydrate sources.

Importantly, the researchers reported that overall calorie intake did not increase substantially despite this dietary shift. Nevertheless, mice consuming the carbohydrate-rich diets still experienced increases in body weight and fat mass.

Rice flour produced similar effects to wheat flour, suggesting the observed metabolic changes were not specific to wheat itself.

Interestingly, mice in the High-fat diet (HFD) + Wheat flour group gained less weight than those in the High-fat diet (HFD) + Chow group, indicating that the interaction between fat and carbohydrate intake may be more complex than previously assumed.

“These findings suggest that weight gain may not be due to wheat-specific effects, but rather to a strong preference for carbohydrates and the associated metabolic changes,” said Professor Matsumura.

Reduced energy expenditure appeared to play a key role

To investigate why the mice gained weight without substantially increasing calorie intake, the researchers carried out further metabolic analysis using indirect calorimetry and respiratory gas measurements.

The findings suggested that the weight gain was not primarily caused by overeating. Instead, the animals appeared to experience reduced energy expenditure, meaning they were burning fewer calories.

Researchers also identified several metabolic changes in the mice consuming the carbohydrate-rich diets.

Blood analysis showed:

• Increased fatty acid levels
• Reduced levels of essential amino acids

Meanwhile, examination of the liver revealed:

• Greater fat accumulation
• Increased activity of genes involved in fatty acid synthesis
• Increased activity of genes associated with lipid transport

Together, these findings suggest that carbohydrate-heavy dietary patterns may alter how the body processes and stores energy.

Metabolic changes improved when carbohydrates were reduced

The researchers also observed that removing wheat flour from the diet rapidly improved both body weight and several metabolic abnormalities.

According to the authors, this finding suggests that moving away from a highly carbohydrate-focused dietary pattern and towards a more balanced eating pattern may help improve metabolic regulation.

However, the researchers emphasised that additional work is needed to determine how these findings translate to human diets and real-world eating behaviour.

Future studies will explore human dietary patterns

The research team says the next phase of investigation will focus on understanding whether similar metabolic effects occur in people.

“Going forward, we plan to shift our research focus to humans to verify the extent to which the metabolic changes identified in this study apply to actual dietary habits,” stated Professor Matsumura.

“We also intend to investigate how factors such as whole grains, unrefined grains, and foods rich in dietary fiber, as well as their combinations with proteins and fats, food processing methods, and timing of consumption, affect metabolic responses to carbohydrate intake. In the future, we hope this will serve as a scientific foundation for achieving a balance between ‘taste’ and ‘health’ in the fields of nutritional guidance, food education, and food development.”

The researchers noted that future studies examining food quality, fibre content, food combinations, and meal timing may help provide a more nuanced understanding of how carbohydrates influence metabolism and body weight.

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Whole Milk and Childhood Obesity – New Study Challenges Long-Standing Dietary Advice

Key Takeaways:

• Children who consumed whole-fat milk in early childhood showed lower odds of living with obesity in later childhood compared with those consuming reduced-fat options
  
• The study found no evidence that whole milk increases adiposity, challenging decades of low-fat dietary guidance
  
• Researchers suggest milk fat may influence satiety and overall dietary patterns, although mechanisms remain unclear
  
  
  

Rethinking milk fat and childhood health

New research from the University of Toronto suggests that children who consume whole-fat milk during early childhood may have a lower likelihood of living with obesity in middle childhood than those who drink reduced-fat milk.

These findings contribute to a growing body of evidence indicating that lower-fat milk may not provide the protective effect against childhood obesity that has long been assumed. For several decades, dietary guidelines in many countries have promoted low-fat dairy products. For example, Canada’s Dietary Guidelines in 2019 continued to recommend reduced-fat options, reflecting a broader historical focus on reducing dietary fat intake.

Study overview and design

The study, published in the American Journal of Clinical Nutrition, is described as one of the most comprehensive analyses to date examining the relationship between milk consumption and childhood obesity over time.

Researchers, including former postdoctoral fellow Tara Zeitoun and doctoral student Zheng Hao Chen, analysed data from the CHILD Cohort Study. This large, prospective study tracks health data from thousands of children from before birth through to adolescence.

Caregivers reported the type of milk consumed by children, including skim, one per cent, two per cent, and whole-fat milk. Researchers then assessed a range of outcomes at ages five and eight, including:

• Body mass index (BMI)
• Waist-to-height ratio
• Fat mass
• Preclinical and clinical obesity status
  
  
  

Key findings

Milk consumption was common among participants, with over 90 per cent of children consuming milk before the age of five. Among these:

• 24 per cent consumed whole-fat milk
• Approximately half consumed less than one cup per day
  

Despite relatively modest intake, notable differences emerged. Children who consumed whole milk at age five had significantly lower BMI at age eight. They also had 69 per cent lower odds of living with obesity compared with children who consumed skim milk.

In addition, researchers identified a broader pattern in which higher milk fat content was associated with more favourable adiposity profiles.

Expert insight

Kozeta Miliku, a professor of nutritional sciences at the University of Toronto’s Temerty Faculty of Medicine and a researcher at the Joannah and Brian Lawson Centre for Child Nutrition, emphasised the implications of these findings:

“The most important learning from this study is that whole milk was not associated with higher adiposity or obesity risks risk in children, and may even be linked to healthier growth patterns,”

She also highlighted the limitations of focusing narrowly on fat reduction:

“Switching to lower-fat milk has been about cutting fat in the diet, but that may miss the bigger picture,” says Miliku. “When we think about healthy growth, it’s important to consider the overall nutritional context. Removing fat does not automatically make skim milk a healthier choice for children.”

Implications for public health guidance

The findings raise important questions about long-standing public health recommendations. Prior to 2019, Health Canada advised that children transition from whole milk to reduced-fat milk from the age of two. Similarly, the Dietary Guidelines for Americans 2020–2025 supported reduced-fat dairy intake.

However, recent policy developments suggest a shift in thinking. In the United States, the Whole Milk for Healthy Kids Act has allowed full-fat milk to be reintroduced into school lunches, aligning with updated national guidance that is more permissive of full-fat dairy.

Possible biological mechanisms

While the study did not directly investigate underlying mechanisms, the researchers proposed several hypotheses:

• Milk fat may enhance satiety, potentially reducing the consumption of energy-dense, nutrient-poor foods
• It may influence overall energy balance
• It could play a role in metabolic pathways linked to growth and nutritional status
  

These potential explanations highlight the complexity of dietary patterns and suggest that focusing on single nutrients may overlook broader physiological effects.

The need for further research

Miliku noted that additional research is needed to better understand how milk fat may influence obesity risk and whether any protective effects persist into adolescence and adulthood.

With Canada’s 2019 dietary recommendations offering limited specific guidance on milk consumption for children, the study’s findings may help inform future discussions among parents, clinicians, and policymakers.

A broader view of healthy diets

Miliku concluded by reinforcing the importance of overall dietary quality:

“Whole fat milk can be part of a healthy diet and does not on its own increase obesity risk,” she adds. “And it’s important to think about the overall quality of the diet – the fruits and vegetables, whole grains and protein-rich foods they consume.”

Funding and support

The research was funded by the Canadian Institutes of Health Research and the Joannah & Brian Lawson Centre for Child Nutrition at the University of Toronto, supported through a donation by President’s Choice Children’s Charity.

CCH insights:

This interesting new research will hopefully be the trigger for governments and public health bodies to review and amend their outdated advice to choose low-fat dairy options instead of full-fat. The reductionist approach to nutrition, which considers food just in terms of calories and individual nutrients, is an oversimplification which does not help our understanding of the relationship between food and health. If the best food for children early in life is whole milk, why would it be beneficial for them to suddenly switch to low-fat milk at the age of 2?

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Visual Signals, Healthier Choices – Study Shows Colour-Coded Labels Influence Consumer Decisions

Key Takeaways:

• Colour-coded nutrition labels are more effective than traditional tables in guiding healthier food choices
  
• Red warning signals have a stronger behavioural impact than green positive cues, reflecting a “negative bias” in decision-making
  
• Simple visual labelling systems may support public health efforts to address obesity and poor dietary habits
  
  
  

The growing use of colour-coded nutrition labels

Colour coding on food packaging is becoming increasingly common, particularly as policymakers and manufacturers seek ways to guide consumers towards healthier dietary choices. A recent study conducted by researchers from SWPS University, the University of Wisconsin, and the University of Massachusetts suggests that these visual systems are significantly more effective than traditional nutritional tables.

The findings, published in Current Psychology, indicate that the effectiveness of colour-coded labels lies in how the brain processes signals of benefit and risk. Rather than requiring effortful interpretation, colour cues allow for rapid, intuitive judgements about a product’s healthfulness.

Obesity and the need for clearer nutritional guidance

According to the World Health Organization, overweight and obesity are major contributors to the development of chronic diseases. Over the past three decades, the proportion of children and adolescents in the United States who are overweight or at risk has more than tripled, reaching 37% and 34% respectively.

This trend has been driven largely by reduced physical activity and the increased consumption of foods high in fat and sugar. In response, clearer and more accessible nutritional labelling systems are being explored as tools to help people make more informed food choices.

How traffic light labelling works

One widely adopted approach is the traffic light labelling (TLL) system, originally developed in the United Kingdom. This system uses colours to indicate the levels of key nutrients such as calories, fat, saturated fat, sugar, and salt relative to recommended intake levels.

• Green indicates low levels, typically below 15% of the reference intake
  
• Red signals high levels, typically exceeding 25% of the reference intake

By translating numerical data into easily recognisable visual cues, the system allows consumers to assess a product’s nutritional profile at a glance.

“A picture is worth a thousand words”

The study aimed to explore the psychological mechanisms behind how people interpret these colour-coded labels.

“We decided to investigate the psychological mechanisms behind the reading of color-coded product labels. We drew on theories about verbal and visual information processing, as well as the perception of information in positive and negative contexts. We wanted to bridge a gap. Previous studies focused exclusively on consumer purchasing behavior and analyzed the extent to which color-coded labels influenced the choice of healthy food products,” says Professor Andrzej Falkowski, a business psychologist from the Institute of Psychology at SWPS University and the author of the study.

To examine this, researchers recruited 79 participants in the United States via Amazon Mechanical Turk. Participants were asked to evaluate products such as chicken noodle soup, ranch dressing, and peanut butter. These products were presented either with colour-coded nutrient indicators or with traditional text-based information.

Participants rated each product on a scale from 0 to 10, where 0 indicated “harmful” and 10 indicated “healthy”.

Faster processing, more intuitive decisions

The findings confirmed that visual information is easier for people to process than text. Colour cues are interpreted almost instantly by the brain, requiring minimal cognitive effort.

This enables individuals to make quick, instinctive judgements about whether a product is beneficial, even in time-pressured situations such as shopping. In contrast, traditional nutritional tables require more deliberate analysis, which may reduce their practical usefulness in real-world settings.

The power of red and the role of negative bias

One of the most striking findings was the disproportionately strong influence of the colour red. While green highlights positive attributes, red signals high levels of fat or sugar and prompts caution.

“This result also aligns with existing theories suggesting that negative events exert a stronger influence on behavior than positive ones. It is this ‘negative bias’ that makes color systems so effective. Red causes us to pause and reconsider a purchase,” Professor Falkowski emphasizes.

This asymmetry – where negative signals carry more weight than positive ones – was not observed with traditional labelling formats. Without clear visual cues, participants found it more difficult to distinguish between beneficial and harmful aspects of a product.

Improved consistency in consumer judgements

The study also found that colour-coded labels led to more consistent evaluations across participants. Because the visual system clearly differentiates between risks and benefits, individuals were better able to assess products in a uniform way.

By contrast, traditional descriptors such as “low fat” can be ambiguous and open to interpretation, particularly for those with limited nutritional knowledge. Colour coding, based on universally recognised traffic signals, offers a more accessible and intuitive alternative.

Implications for public health and obesity prevention

The researchers suggest that these findings have important implications for public health policy.

“Given the ongoing global challenges of obesity and poor dietary habits, color-coded labeling represents a simple yet impactful strategy for guiding healthier consumer choices,” Falkowski says.

By enhancing the visibility and clarity of nutritional information, colour-coded systems may encourage people to select healthier options. Over time, such behavioural shifts could contribute to improvements in population health.

The authors conclude that leveraging visual attention mechanisms and simplifying complex nutritional data may be a practical and scalable approach to addressing poor dietary habits and the global rise in obesity.

CCH insights:

The results of this study supports the use colour-coded labelling system as it enables quick health-based decision-making, with minimal time or effort required. And it also revealed that we use the system more to avoid unhealthy ‘red’ foods than to actively choose healthy ‘green’ foods. These outcomes emphasise the complex range of factors that contribute to shopping behaviours and decisions about what people eat. And if we want to encourage people to eat healthily, we need to understand these factors better and consider how best to influence them.

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AI Diet Recommendations for Adolescents Show Significant Nutritional Gaps, Study Finds

Key Takeaways:

• AI-generated diet plans consistently underestimated energy and key macronutrients required by adolescents
  
• Macronutrient balance was frequently misaligned with clinical guidelines, with lower carbohydrates and higher fat and protein levels
  
• Researchers caution that AI tools should not replace dietitians for adolescent nutrition without professional oversight
  
  
  

Growing demand for accessible nutrition support

Artificial intelligence is increasingly being used to support dietary planning, particularly in areas where access to qualified professionals is limited. However, a new study published in Frontiers in Nutrition raises important concerns about the reliability of these tools when applied to adolescents living with overweight or obesity.

Globally, adolescent overweight and obesity are rising at pace, affecting an estimated 390 million young people in 2022. In many regions, this now represents the most common form of malnutrition. Excess body weight in adolescence is associated with a range of adverse health outcomes, including type 2 diabetes, dyslipidaemia, hypertension, and sleep apnoea. It also increases the likelihood of obesity in adulthood and is linked to reduced quality of life.

Alongside physical health risks, adolescents may experience body image concerns and engage in harmful weight control behaviours such as self-induced vomiting or misuse of laxatives.

Dietary modification remains central to improving outcomes. Dietitians play a key role in delivering tailored, evidence-based nutrition plans aligned with established guidelines. However, limited access and workforce pressures can restrict the availability of personalised support.

AI tools, including chatbots and large language models, are increasingly being explored as a way to bridge this gap. While they can provide general dietary guidance, concerns remain about their accuracy, safety, and ability to replicate the individualised care provided by trained professionals.

Study design – comparing AI models with dietitian plans

To better understand the role of AI in adolescent nutrition, researchers conducted a direct comparison between AI-generated diet plans and those created by a dietitian.

Five AI systems were evaluated: ChatGPT-4o, Gemini 2.5 Pro, Claude 4.1, Bing Chat-5GPT, and Perplexity. Across two sessions, these models generated a total of 60 diet plans. Each plan covered three days and was based on four standardised adolescent profiles, including boys and girls living with overweight or obesity.

These AI-generated plans were compared with dietitian-designed one-day plans developed in line with established nutritional recommendations. The reference plans followed a macronutrient distribution of:

• 45–50 % carbohydrates
• 30–35 % fat
• 15–20 % protein

The researchers then analysed energy intake, macronutrient composition, micronutrient content, safety, and feasibility.

Consistent underestimation of energy and macronutrients

The findings revealed a clear and consistent pattern across all AI models. Diet plans generated by AI underestimated both total energy intake and key macronutrients when compared with dietitian-designed plans.

On average:

• Energy intake was lower by 695 kcal
• Protein intake was reduced by 20 g
• Fat intake was reduced by 16 g
• Carbohydrate intake was reduced by 115 g

Given the high energy demands of adolescence, such deficits could have meaningful clinical implications, particularly for growth, development, and overall health.

Macronutrient imbalance – a shift away from guidelines

Beyond total intake, the balance of macronutrients was also significantly altered in AI-generated plans.

Some AI models recommended:

• Protein intake up to 23.7 %
• Fat intake up to 44.5 %

Both values exceeded recommended levels. In contrast, carbohydrate intake accounted for no more than 36.3 %, falling below guideline recommendations.

Dietitian-designed plans, by comparison, remained closely aligned with clinical standards:

• Carbohydrates: 44 %–46 %
• Protein: 18 %–20 %
• Fat: 36 %–37 %

The authors noted:

“This pattern illustrates a systematic shift across all AI models to lower CHO, higher protein, and higher lipid meal structures, indicating that the macronutrient balance, not just the amount of gram-based nutrients, is significantly disrupted in AI-generated plans.”

Researchers suggest that AI models may be influenced by popular dietary trends, such as low-carbohydrate or ketogenic approaches, rather than evidence-based adolescent nutrition guidelines. This shift may pose risks during a critical period of physical and cognitive development.

Micronutrient variability raises additional concerns

In addition to macronutrient discrepancies, the study identified significant variability in micronutrient composition across AI-generated plans.

No model consistently matched the dietitian-designed reference diet across all nutrients. This inconsistency raises concerns about potential micronutrient deficiencies, which could further compromise adolescent health.

The findings suggest that AI tools currently lack the technical precision required to accurately estimate both macro- and micronutrient needs in personalised dietary plans for adolescents.

Strengths and limitations of the study

The study offers several notable strengths. It evaluated multiple AI models, allowing for robust comparison across systems. The use of three-day diet plans enabled identification of consistent patterns rather than isolated outputs. Dietitian-designed plans provided a credible clinical benchmark, and the inclusion of both macro- and micronutrient analysis allowed for a comprehensive assessment of dietary quality.

However, there are limitations to consider. The findings are specific to the models tested, which are rapidly evolving. Standardised adolescent profiles may not fully capture real-world complexity, limiting personalisation. The use of simulated scenarios rather than real-life behaviours may reduce ecological validity. Additionally, prompts were standardised and delivered in a single language, which may limit generalisability across populations.

Implications for clinical practice and AI use

The study highlights important risks associated with the unsupervised use of AI for adolescent dietary planning.

As the authors conclude:
“AI models have exhibited clinically significant deviations in diet plans for adolescents at both macro and micro levels.”

These deviations include consistently lower energy and carbohydrate recommendations compared with dietitian-designed plans.

Until these limitations are addressed, AI-generated diet plans should be used with caution. They may serve as a supplementary tool under professional supervision, but they are not currently a safe or reliable substitute for qualified dietary guidance in adolescents.

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