Study reveals sweet tooth linked to increased risk of depression, diabetes, and stroke
Individuals with a preference for sweet foods and sugary drinks face a significantly higher risk of developing conditions such as depression, diabetes, and stroke, according to groundbreaking research from the University of Surrey. The study, which highlights the complex interplay between dietary habits and long-term health, was recently published in the Journal of Translational Medicine.
The research team analysed anonymised dietary data from 180,000 volunteers from the UK Biobank, a large-scale biomedical database, and utilised artificial intelligence (AI) to categorise participants into three distinct dietary profiles based on their food preferences:
- Health-conscious: This group prioritises fruits, vegetables, and plant-based foods, showing a clear preference for healthier options over animal-based or sweet foods.
- Omnivore: These individuals enjoy a balanced variety of foods, including meats, fish, vegetables, and occasional sweets and desserts.
- Sweet tooth: This group has a strong preference for sugary foods and drinks, while showing less interest in healthier options such as fruits and vegetables.
To explore how these preferences might impact health, the researchers examined blood samples from participants, measuring 2,923 proteins and 168 metabolites. These biological markers offer insight into how the body processes nutrients and its overall functioning. Proteins, for instance, are crucial for bodily processes such as immune defence, muscle function, and brain activity. Metabolites are small molecules produced during digestion and other metabolic processes, providing a snapshot of the body’s internal health.
By comparing the levels of these proteins and metabolites across the three groups, the researchers uncovered distinct biological differences, offering a deeper understanding of how diet impacts health.
Professor Nophar Geifman, lead author of the study and Professor of Health and Biomedical Informatics at the University of Surrey, explained, “The foods that people like or dislike appear to have a direct link to their health. If someone regularly chooses cakes, sweets, and sugary drinks, our study suggests that this preference may have detrimental effects on their overall well-being.”
The study revealed that individuals in the sweet tooth group were 31% more likely to experience depression. Additionally, they had notably higher rates of diabetes and vascular heart conditions compared to those in the other two groups.
“Importantly, by using data-driven AI methods, we were able to identify these groups based on food preferences, and these groups turned out to be quite meaningful in relation to health outcomes and biological markers,” added Professor Geifman.
Sugar is often an integral part of many people’s diets, and the study reinforces concerns about the widespread consumption of processed sugar. “As a society, we should be more mindful of our food choices. While it is not about dictating what people should eat, our goal is to provide information that helps individuals make informed decisions about their diets,” said Geifman.
In addition to examining proteins and metabolites, the researchers also reviewed standard blood biochemistry tests for participants in each dietary group. The results were concerning for the sweet tooth group, who displayed elevated levels of C-reactive protein, a marker of inflammation, as well as higher glucose levels and poor lipid profiles, which are risk indicators for diabetes and cardiovascular disease.
In contrast, the health-conscious group, which consumed more dietary fibre, exhibited lower risks of heart failure, chronic kidney disease, and stroke. Meanwhile, the omnivore group demonstrated moderate health risks, falling between the other two groups.
Professor Geifman further noted, “In those with a sweet tooth, we found several red flags in their blood tests, including markers for inflammation and poor lipid profiles. These are significant warning signs for serious conditions like diabetes and heart disease.”
The findings add to the growing body of evidence highlighting the negative impact of excessive sugar consumption on health. According to the British Nutrition Foundation, individuals in the UK consume between 9% to 12.5% of their daily calorie intake from “free sugars”—these are sugars added to foods and drinks. Popular sources of free sugars for adults include biscuits, cakes, pastries, and fruit pies, while sugary soft drinks and alcoholic beverages are also major contributors.
This study underscores the urgent need for greater awareness around dietary habits and their long-term implications on mental and physical health. While occasional treats may not seem harmful, consistently choosing sugar-laden foods and drinks could increase the likelihood of developing serious health conditions over time.
As Professor Geifman emphasised, “These findings serve as a reminder that the choices we make about what we eat can have lasting consequences on our health. While no one is saying people should entirely eliminate their favourite foods, moderation and a focus on healthier options could greatly reduce the risk of these debilitating conditions.”
This new research provides a compelling argument for reconsidering dietary habits, particularly for those with a sweet tooth, and for taking proactive steps to improve overall well-being through mindful eating.
Read MoreDaily Brazil nut consumption may reduce inflammation and support gut health, new study suggests
Brazil nuts are one of the most concentrated sources of selenium, a trace mineral that plays a crucial role in the body’s antioxidant defences, immune response, and thyroid hormone metabolism. Selenium deficiency has been linked to several health issues, including chronic inflammation and impaired gut health.
Low levels of selenium in the bloodstream have been associated with inflammation-related conditions, including gut health challenges. Research has also identified connections between obesity, inflammation, and gut issues such as increased intestinal permeability, commonly known as “leaky gut.” This condition may occur when inflammation and body fat levels rise, causing the tight junctions in the cells lining the intestines to loosen. When these junctions become less effective, antigens, toxins, and bacteria may enter the bloodstream, triggering further inflammation, thus creating a harmful cycle where obesity exacerbates intestinal permeability, and vice versa.
In a recent study, researchers examined the impact of daily consumption of Brazil nuts on inflammation and intestinal permeability, specifically focusing on women living with overweight or obesity, during an 8-week calorie-restricted diet. The study’s findings, published in The Journal of Nutrition, suggest that eating 8 grams of Brazil nuts per day could improve these health markers, likely due to their rich selenium content.
The Brazil nuts used in the study were sourced from Amazonas, Brazil, and donated by ECONUT. However, attempts to contact ECONUT for comment were unsuccessful at the time of publication, and their involvement in the study was not noted as a conflict of interest.
The Study’s Design and Findings
The study was conducted by researchers from the Department of Nutrition and Health at the Universidade Federal de Viçosa in Brazil between June 2019 and September 2021. It involved 56 women aged 20 to 55, with an average age of 34 years. The women were categorised as either living with overweight or obesity, with 17.4% having specific cardiometabolic risk factors and 82.6% living with obesity, regardless of risk factors.
Participants were excluded from the study if they were pregnant, lactating, menopausal, athletes, vegan, had certain medical conditions, were using specific medications, had experienced significant weight changes, regularly consumed nuts, or had other potential study interferences.
The participants were divided into two groups: a control group and a Brazil nut group. Both groups followed a customised menu designed to provide approximately 500 fewer calories than their estimated daily energy requirements. The macronutrient composition of the diet was 50% carbohydrates, 30% fats, and 20% proteins, in line with established obesity management guidelines. Each participant was encouraged to lose at least 4 kilograms over the 8-week period.
To ensure a balanced intake of fats and calories, both groups were provided with controlled-ingredient salad dressings:
- Control group: Followed a nut-free diet and consumed 10 grams of soybean oil-based salad dressing with lemon daily.
- Brazil nut group: Consumed 8 grams of Brazil nuts (providing 347.2 micrograms of selenium) as a morning snack and 5 grams of canola oil-based salad dressing with lemon each day.
Participants received bi-weekly counselling from a nutritionist who monitored their diet adherence, including alcohol consumption. Any participant who failed to adhere to the study protocol was excluded from the final analysis.
Researchers measured inflammatory markers in the blood and selenium levels. Intestinal permeability was assessed using the lactulose/mannitol test (LM ratio), and statistical analyses were conducted to evaluate changes between the groups, with a 97% power to detect differences in intestinal permeability.
Brazil Nuts Associated with Reduced Inflammation and Improved Gut Health
Of the 56 women initially recruited, 46 completed the study. At the start, the control group had a higher intake of polyunsaturated fats compared to the Brazil nut group. During the 8-week intervention, the control group reduced their intake of saturated fats, while the Brazil nut group increased their intake of polyunsaturated fats and dietary fibre.
Both groups achieved similar calorie restrictions and experienced modest weight loss (approximately 3 kilograms) and small reductions in waist circumference. However, the Brazil nut group showed a significant increase in selenium levels, confirming adherence to their Brazil nut consumption.
Compared to the control group, the Brazil nut group exhibited lower levels of inflammatory markers, including C-reactive protein (CRP), tumour necrosis factor (TNF), interleukin-1β (IL-1β), and interleukin-8 (IL-8), indicating a reduction in systemic inflammation. In the Brazil nut group, CRP levels decreased from 7.1 mg/L to 5.6 mg/L over the 8 weeks, while the control group saw an increase in CRP levels from 8.0 to 9.4 mg/L. Although the exact mechanism behind these changes is not fully understood, it is likely linked to improvements in gut inflammation and intestinal permeability.
Women in the Brazil nut group who lost more weight also showed more pronounced reductions in CRP levels. Additionally, this group demonstrated lower lactulose excretion and LM ratio values, which are markers of improved intestinal permeability. However, these changes were not statistically significant when compared to the control group.
Further analysis revealed that higher blood selenium levels were associated with lower levels of IL-1β and IL-8, and changes in IL-8 were related to the LM ratio. These findings suggest that selenium levels may predict improvements in both systemic inflammation and gut permeability.
Study Limitations and Expert Insights
This study had certain limitations, including its small sample size, short duration, and the fact that it only included young to middle-aged women from Brazil. As a result, the findings may not be generalisable to other populations. The participants were also not blinded to their dietary interventions, the study was not randomised, and calorie restriction adherence was primarily self-reported, which may have introduced reporting errors.
Commenting on the study, registered dietitian Alyssa Simpson, RDN, CGN, CLT, who was not involved in the research, highlighted the need for further studies to isolate the effects of selenium from other dietary variables. She stated: “The findings indicate that selenium from Brazil nuts significantly influences inflammation and intestinal permeability, but the simultaneous increases in polyunsaturated fats and fibre intake complicate attributing the effects solely to selenium.”
Simpson suggested that a more controlled study design could help clarify the individual effects of selenium, polyunsaturated fats, and fibre on inflammation and gut health.
Dr. Thomas M. Holland, a physician-scientist from the RUSH Institute for Healthy Aging, added: “In this study, increased selenium levels correlated with reductions in inflammatory cytokines and improvements in intestinal permeability, which may enhance the absorption of nutrients.”
How Many Brazil Nuts Should You Eat Per Day?
Kiran Campbell, RDN, a medical nutrition advisor, explained that the human body cannot produce selenium, making dietary intake essential. While a single Brazil nut provides approximately 96 micrograms of selenium—nearly double the recommended daily intake for most adults—experts recommend consuming just 1–2 Brazil nuts per day to avoid exceeding the safe upper limit of 400 micrograms of selenium per day.
The European Food Safety Authority (EFSA) has set a lower upper limit of 255 micrograms of selenium daily for adult men and women. Consuming too much selenium can lead to toxicity, with symptoms such as brittle nails, hair loss, skin rashes, and neurological issues.
In conclusion, incorporating 1–2 Brazil nuts daily may offer practical and beneficial effects in reducing inflammation and supporting gut health, but they should be consumed as part of a well-rounded, healthy diet.
Read MoreYoyo dieting disrupts gut health and drives weight regain and inflammation
A review from Deakin University, Australia, published in Nutrients, reveals the profound effects of yoyo dieting (cycles of weight loss and regain) on gut health. The review highlights how weight cycling leads to gut inflammation, changes in microbiota, and adaptations in the sympathetic nervous system (SNS), which together drive weight regain.
Background
Obesity now affects over half of the global adult population and is linked to millions of deaths from diseases such as cardiovascular disease and type 2 diabetes. One of the major challenges in managing obesity is sustaining weight loss. Studies show that most people regain lost weight within five years, a phenomenon known as yoyo dieting or weight cycling.
This weight cycling not only increases the risk of obesity-related conditions but also disrupts gut health. The review points to emerging evidence that weight regain alters gut microbiota, with adaptive metabolic responses further complicating long-term weight management.
Gut Hormones and Energy Balance
Energy balance—the balance between intake and expenditure—is regulated by signals from the gut, pancreas, and adipose tissue. Many of these signals come in the form of peptide hormones that either promote satiety or stimulate hunger. After weight loss, individuals often experience lower levels of satiety hormones (PYY, GLP-1, and CCK) and higher levels of hunger hormones like ghrelin. This hormonal imbalance makes maintaining weight loss difficult, driving overeating and weight regain.
The review also discusses how weight loss can reduce enteroendocrine cells (EECs), which produce these key hormones, further impairing the body’s ability to regulate hunger and satiety.
The Role of the Gut Microbiota
The gut microbiota, which plays a critical role in energy regulation, also undergoes changes during and after weight loss. Beneficial bacteria that produce short-chain fatty acids (SCFAs), such as Christensenella and Lactobacillus reuteri, often decline during yoyo dieting, impairing satiety and promoting weight regain. Conversely, weight regain is associated with an increase in pro-inflammatory bacteria, such as Desulfovibrio and Ruminococcus, which contribute to metabolic disorders and gut inflammation.
Yoyo Dieting and Inflammation
Yoyo dieting exacerbates obesity-related chronic inflammation. Studies show that weight regain triggers inflammatory responses in the gut, marked by elevated levels of inflammatory markers such as TNF-α and IL-6. This inflammation can compromise gut barrier function, worsening metabolic health.
Improving Gut Health After Weight Loss
While yoyo dieting is associated with negative changes in the gut, weight loss has been shown to improve gut health by reducing inflammation and promoting the growth of beneficial bacteria like Akkermansia and Bifidobacterium. However, research indicates that the gut microbiota may take considerable time to return to a healthier state, leaving individuals vulnerable to weight regain during this period.
Research Gaps and Conclusions
Though animal studies have highlighted important links between yoyo dieting and gut health, more human studies are needed to fully understand how weight cycling affects the gut microbiota and weight regain. The review concludes that while weight loss can improve gut health, the molecular mechanisms behind these changes are still unclear, and more research is needed to develop effective strategies for preventing weight regain.
In conclusion, yoyo dieting disrupts gut health, leading to hormonal imbalances, inflammation, and microbiota changes that drive weight regain. Addressing these factors could be key to improving long-term weight maintenance and reducing obesity-related health risks.
Read MoreIncreased protein and fibre intake linked to effective long-term weight loss, study reveals
A recent study has revealed that participants in a one-year dietary education programme who experienced the most significant weight loss consumed notably higher amounts of protein and fibre. Among this group, 41% of all 22 participants successfully lost an average of 12.9% of their body weight, while those who were less successful saw a reduction of only slightly over 2%.
The research highlights the critical importance of personalised, adaptable weight loss programmes, which enable individuals to adhere to their diet plans more effectively. According to the researchers, these flexible programmes empower participants to tailor their approaches, maximising long-term success.
The study’s participants were involved in the Individualised Diet Improvement Programme (iDip), a highly customised dietary intervention that equips individuals with the knowledge and tools to develop effective weight loss strategies. The iDip programme incorporates visualisation tools and intensive dietary education to help participants better understand key nutrients, allowing them to create safe, tailored, and sustainable weight loss plans.
“Flexibility and personalisation are key in creating programmes that optimise dieters’ success at losing weight and maintaining that loss,” explained Professor Manabu T. Nakamura, a professor of nutrition at the University of Illinois Urbana-Champaign in the United States and leader of the research.
He continued, “Sustainable dietary change, which varies from person to person, must be achieved to maintain a healthy weight. The iDip approach allows participants to experiment with various dietary iterations, and the knowledge and skills they develop while losing weight serve as the foundation for sustainable maintenance.”
The programme focuses on increasing the intake of protein and fibre, all while keeping daily caloric consumption within the limit of 1,500 calories.
Protein and Fibre: Key Nutrients for Success
For all 22 study participants, the iDip research team developed an innovative, two-dimensional quantitative data visualisation tool. This tool plots the density of protein and fibre in foods per calorie, and it provides a target range for each meal. Participants attended 19 dietary education sessions during the year-long programme, with additional prescribed homework to reinforce their learning and commitment.
Participants were encouraged to create personalised plans based on their usual dietary preferences, with a specific focus on boosting their intake of protein and fibre. The study’s goal was for participants to consume approximately 80 grams of protein and 20 grams of fibre daily.
Throughout the programme, researchers monitored participants’ eating habits and tracked their weight via Wi-Fi-enabled scales. They discovered strong inverse correlations between protein and fibre intake and weight loss at both the three-month and twelve-month marks.
“The strong correlation suggests that participants who were able to develop sustainable dietary changes within the first three months continued to lose weight in the subsequent months. In contrast, those who struggled to implement lasting dietary changes early on rarely succeeded in making significant progress later,” noted Professor Nakamura.
The study’s findings align with broader industry recognition of the role protein plays in effective weight loss. Major nutrition companies, such as Nestlé, have introduced high-protein, portion-controlled foods that can complement individuals’ diets, particularly for those using weight-loss medications.
Weight Loss Results: A Closer Look
Published in Obesity Science & Practice, the study examined the experiences of nine men and thirteen women, aged between 30 and 64. All participants reported having made at least two previous attempts to lose weight before enrolling in the programme.
The study population also presented with various health conditions: 54.6% had high cholesterol, 50% experienced skeletal issues, 36.4% had hypertension, 36.4% had sleep apnoea, and 31.8% had a history of depression. Additionally, some participants were diagnosed with diabetes, non-alcoholic fatty liver disease, and cancer.
On average, participants lost 6.49% of their body weight over the 12-month period. Of the nine individuals who achieved a reduction of more than 5% of their initial body weight, two participants reached a body mass index (BMI) of 25 kg/m², which is within the normal weight range. For these successful participants, researchers found that 78% of their weight loss was attributable to fat reduction.
The study revealed a notable difference in weight loss outcomes for participants with depression. Individuals living with depression experienced a significantly lower weight reduction, averaging a 2.4% decrease in body weight, compared to 8.39% for those without depression. However, there were no significant differences in weight loss outcomes based on other health conditions, age, or gender.
Preservation of Lean Body Mass
One of the key findings of the study was the participants’ ability to reduce fat mass without sacrificing lean body mass. On average, participants’ fat mass decreased from 42.6 kg at the start of the programme to 35.7 kg by the end of the 12-month period. Notably, both successful and unsuccessful participants were able to preserve their lean body mass, a critical factor in maintaining metabolic health during weight loss.
Nakamura emphasised the importance of preserving lean body mass during weight loss, particularly for individuals who are using weight-loss medications.
“Recently, the popularity of injectable weight loss medications has been increasing,” he remarked. “However, using these medications when food intake is minimal will cause serious side effects, including muscle and bone loss, unless protein intake is increased during weight loss.”
The researchers underscored the importance of maintaining a high-quality diet, particularly for individuals taking anti-obesity medications. Earlier in the year, medical experts developed a set of evidence-based nutritional guidelines to assist healthcare professionals in supporting patients who are using such medications.
Conclusion
The study demonstrates that higher intakes of protein and fibre are strongly linked to more successful weight loss outcomes in individuals following a personalised dietary programme. The findings highlight the importance of flexible, tailored approaches to weight loss that prioritise nutrient-rich foods while maintaining adequate caloric intake. For individuals using weight-loss medications, attention to dietary quality, especially protein intake, is essential to preserving muscle mass and preventing adverse health effects.
Read MoreRising BMI and fat mass linked to ultra-processed food consumption in young Chilean children
A recent study published in BMC Medicine has illuminated the significant relationship between the consumption of ultra-processed foods (UPFs), rising obesity rates, and certain metabolic indicators among preschool-aged children in Chile. The findings underscore the potential long-term health risks associated with diets high in UPFs, particularly in young children, a demographic increasingly vulnerable to the adverse effects of poor nutrition.
Study Overview
The study was conducted as part of the Food and Environment Chilean Cohort (FECHIC) study, a prospective cohort investigation designed to explore the impact of dietary habits on health outcomes in Chilean children. The researchers focused on the influence of UPF consumption on obesity and metabolic outcomes over a two-year period, with initial data collection beginning in 2016.
Participant Selection and Data Collection
The study analysed dietary data from 962 children, all of whom were around four years old at the start of the research. Dietary intake information was collected using the United States Department of Agriculture’s (USDA) multiple-pass technique, a method known for its accuracy in capturing 24-hour dietary recalls. Mothers served as the primary respondents, providing detailed accounts of their children’s food intake during structured in-person interviews. Where necessary, the children themselves contributed additional details about their eating habits, especially for meals consumed outside the home, such as during school hours.
In order to maintain the integrity of the study, records indicating extreme levels of UPF consumption were excluded. The researchers utilised the NOVA classification system to categorise all foods consumed by the participants. This system divides foods into four categories: natural and minimally processed foods, processed culinary ingredients, processed foods, and ultra-processed foods. To estimate the children’s UPF consumption both in terms of grams and calories, the Multiple Source Method (MSM) was employed.
Assessment of Adiposity and Metabolic Indicators
Two years after the initial data collection, when the children had reached the age of six, the research team measured various indicators of adiposity and metabolism. Adiposity indicators included waist circumference, body fat mass (both as a percentage and in kilograms), and body mass index (BMI) z-scores. The metabolic indicators assessed were fasting blood glucose levels, insulin levels, the homeostatic model assessment for insulin resistance (HOMA-IR), low-density lipoprotein cholesterol (LDL-c), high-density lipoprotein cholesterol (HDL-c), triglycerides, and total cholesterol.
To evaluate the children’s energy requirements, the Dietary Reference Intake (DRI) equation was applied. The relationship between UPF intake and the various health outcomes was analysed using linear regression models, which were adjusted for covariates such as age, sex, baseline BMI z-scores, screen time, and maternal factors including BMI, age, education, employment status, and socioeconomic status.
Results and Analysis
At the beginning of the FECHIC study, the average age of the children was five years, with a slight female majority (52%). The average BMI z-score was recorded at 1.0, indicating a tendency towards overweight. The mothers were, on average, 31 years old, with 55% having attained a medium level of education.
By the end of the two-year study period, the average fat mass of the children had risen to 24%, and the average fasting glucose level was measured at 82 mg/dL. Notably, UPFs accounted for 48% of the children’s total caloric intake at four years of age, and 39% of their total food intake by weight. Despite UPFs contributing the majority of calories, minimally processed foods still constituted the largest portion by weight (57%).
The adjusted regression models revealed significant positive associations between UPF consumption and several key indicators of obesity, including BMI, waist circumference, fat mass in kilograms, and percentage fat mass. However, the study did not find a direct relationship between UPF intake and the metabolic markers assessed.
Sensitivity analyses, which included models without the use of stabilised inverse probability of censoring weights and considered UPF intake in quartiles, produced consistent results, further reinforcing the study’s findings.
Discussion
The study’s results suggest that the proportional contribution of UPFs to the diet is more impactful than the total quantity consumed. This observation aligns with broader research indicating that health improvements often follow a shift away from diets dominated by ultra-processed foods.
UPFs are typically characterised by a poor nutritional profile, with high levels of added sugars and saturated fats, and low concentrations of essential vitamins and minerals. The production processes involved in creating UPFs often use refined ingredients that not only reduce satiety but also increase glycaemic response, leading to a higher propensity for overeating. Additionally, UPFs are energy-dense but low in water content, allowing for rapid consumption of both volume and calories, which further promotes excessive intake. The low protein density in these foods may also contribute to an overconsumption of other, potentially unhealthy, foods.
There is also concern that the widespread consumption of UPFs increases exposure to rare or unnatural food additives, which could pose additional, as yet unquantified, health risks.
Conclusion and Recommendations
The findings from this study indicate a clear link between UPF consumption and rising obesity rates among Chilean preschoolers, though no significant connection to metabolic consequences was observed within the two-year period. Longer follow-up studies are necessary to fully understand the long-term risks associated with UPF consumption in young children.
In light of these findings, health authorities and policymakers are urged to strengthen global initiatives aimed at creating environments that encourage diets rich in minimally processed foods. There is a pressing need to restrict children’s access to UPFs, which are increasingly prevalent in modern diets, to curb the growing trend of childhood obesity and its associated health risks.
Read MoreThe impact of high-protein diets on weight, energy, and blood sugar regulation
Over the past two decades, there has been a marked increase in interest surrounding the role of dietary protein in enhancing health outcomes. This heightened attention is largely driven by growing evidence that links protein intake with a variety of metabolic benefits. A recent comprehensive review published in Frontiers in Endocrinology delves into the effects of dietary protein on energy intake, appetite regulation, and postprandial blood sugar levels, offering valuable insights into both the short-term and long-term impacts of protein consumption.
Immediate Effects of Protein Consumption
Current research suggests that high-protein diets play a significant role in promoting weight loss, reducing weight gain, and improving glycaemic control. One of the key benefits of protein intake is its ability to lower postprandial (after eating) blood sugar levels and suppress energy intake. These effects are thought to be linked to protein’s capacity to stimulate gastrointestinal (GI) hormones and other post-absorptive mechanisms. Additionally, protein consumption has been shown to reduce hunger and increase feelings of fullness, with these effects being dose-dependent in both healthy and obese individuals.
A notable meta-analysis has highlighted the ability of protein-rich diets to reduce hunger, lower food intake, and diminish the desire to eat, while simultaneously increasing feelings of fullness. This reduction in postprandial blood sugar levels is one of the mechanisms through which protein aids in appetite control. However, it is important to note that the benefits of increased protein consumption may only last for a period of six to twelve months.
Comparative studies on various protein sources have produced interesting findings. For example, preloads containing milk proteins such as casein or whey, as well as proteins from turkey, egg, tuna, or soy, have been evaluated for their effects on satiety and blood sugar regulation. Among these, whey protein has been found to have the most profound impact on reducing blood sugar levels, although some studies suggest that it might be less satiating than other proteins. Nevertheless, milk proteins have consistently demonstrated a stronger ability to lower blood glucose compared to proteins derived from peas, eggs, or fish.
The digestion of proteins and their by-products stimulates the release of GI hormones such as incretins, cholecystokinin (CCK), glucose-dependent insulinotropic polypeptide (GIP), glucagon-like peptide 1 (GLP-1), and peptide tyrosine-tyrosine. These hormones are crucial in the regulation of postprandial blood sugar levels as they are transported to peripheral organs where they increase pyloric pressure and insulin secretion. This, in turn, helps to reduce blood sugar levels after meals.
The effects of different proteins on GI functions also vary, with whey protein generally showing greater efficacy than other sources. For instance, a study involving intraduodenal (directly into the duodenum) infusion of whey protein revealed a dose-dependent stimulation of plasma CCK, GLP-1, and pyloric pressures in both lean and obese participants. The high content of branched-chain amino acids, particularly isoleucine and leucine, in whey protein is thought to contribute significantly to its ability to reduce glycaemia and energy intake.
Medium- and Long-Term Effects
The impact of high-protein diets on weight loss has been extensively studied, particularly through ad libitum (eating at one’s own discretion) and energy-restricted dietary interventions. Regardless of the method employed, diets rich in protein have consistently led to greater weight loss compared to standard diets, especially in interventions lasting up to six months. Interestingly, ad libitum high-protein diets appear to be particularly effective.
A meta-analysis of 24 clinical trials observed a modest but significantly greater reduction in body weight and fat mass with an isocaloric energy-restricted high-protein diet compared to a standard diet over an average period of 12 weeks. Another meta-analysis, encompassing 74 trials, reported reductions in body weight, waist circumference, and body mass index (BMI) following six months on a high-protein diet.
However, the long-term effects of high-protein diets remain less clear, as studies extending beyond one year are limited. For instance, a meta-analysis of 15 clinical trials with interventions lasting at least 12 months found no clear benefits or detriments associated with high-protein intake concerning sustained weight loss. One 12-month study did observe modest improvements in weight maintenance with a high-protein diet compared to diets high in fat or carbohydrates, but the overall evidence remains inconclusive.
Plant Versus Animal Protein
The source of dietary protein—whether plant-based or animal-based—also plays a crucial role in determining health outcomes. Numerous studies have indicated that consuming large amounts of animal protein may increase the risk of developing diabetes, while plant proteins tend to offer protective effects.
Epidemiological studies consistently show a correlation between high animal protein intake, weight gain, and an elevated risk of obesity. For example, one study found that higher daily consumption of total and animal protein, predominantly sourced from chicken and red meat, was associated with significant weight gain over a period of 6.5 years.
In contrast, plant protein consumption has not been linked to either protective or adverse outcomes. In a study investigating the relationship between different protein sources and long-term weight gain across three cohorts, animal proteins were independently associated with weight gain over four years, whereas plant proteins were linked to weight loss.
Moreover, long-term consumption of animal proteins has been frequently associated with an increased risk of diabetes, while plant proteins appear to have neutral or even protective effects. The mechanisms underlying these differences are not entirely understood, but they may involve factors such as the glycaemic load, amino acid composition, and the insulinotropic (insulin-stimulating) effects of animal proteins, which could contribute to the beneficial effects observed with plant protein consumption.
Conclusion
There is substantial evidence supporting the role of increased protein intake in improving glycaemic control and promoting weight loss, particularly in the context of high-protein diets. However, the long-term health benefits of such diets are not yet fully understood, and more comprehensive, longitudinal studies involving diverse populations are needed to draw definitive conclusions. As research continues to evolve, it is clear that both the quantity and source of dietary protein are critical factors in determining the overall impact on health.
Read MoreWalnut consumption linked to lower obesity rates in young women, study reveals
A recent study conducted by researchers at the Indiana University School of Public Health-Bloomington, USA, and funded by the California Walnut Commission, has uncovered a significant connection between walnut consumption and lower rates of obesity, particularly in younger women. This research highlights the potential role of walnuts and other nuts in promoting healthy weight management.
The study, published in the Current Developments in Nutrition journal, focused on the dietary habits of over 19,000 adolescents and young adults in the United States. The data was drawn from the National Health and Nutrition Examination Survey, encompassing individuals aged between 12 and 19 years for adolescents and 20 and 39 years for young adults. The research aimed to explore the relationship between walnut consumption and obesity-related metrics, including Relative Fat Mass (RFM), a validated tool used to estimate body fat percentage and regional fat distribution.
Dr Carla Miller, a Professor of Nutrition at Indiana University School of Public Health-Bloomington, commented on the findings: “While additional research is needed, these results showed that food should not be judged based on calories alone. The addition of nuts, like walnuts, as a part of a healthy eating pattern, may help lower the risk of obesity.”
She added, “Whether it is a handful as a snack or part of a meal, even in small amounts, nuts, including walnuts, can and should be a part of a nutritious diet to support well-being.”
The study’s findings were particularly striking among young women who regularly consumed walnuts. This group exhibited a significantly lower prevalence of obesity compared to their peers who did not include walnuts or other nuts in their diets. The protective effects of walnuts were less pronounced in other demographic groups. For example, young men and adolescent boys who consumed walnuts did not show a statistically significant reduction in obesity rates. However, adolescent girls and young women who consumed any type of nuts, including walnuts, had a noticeably lower RFM than those who did not consume nuts.
Interestingly, the study revealed an unexpected trend among young men who consumed both walnuts and other types of nuts. This group was found to have a higher likelihood of obesity, a result not observed among adolescent boys. This inverse association suggests that the relationship between nut consumption and obesity may vary based on gender and age, underscoring the complexity of dietary impacts on health.
The researchers caution that while these findings are promising, further studies are needed to confirm the observed associations and better understand the underlying mechanisms. The current research suggests a potential link between a walnut-rich diet and lower body fat levels, but more comprehensive studies are required to establish causality.
One of the study’s notable findings was the generally low consumption of nuts across the population. Despite the potential health benefits, 76% of adolescents and 69% of young adults reported not consuming walnuts daily. Additionally, the average intake of nuts in all groups fell well below the recommended daily amount of 56 to 85 grams. Adolescents averaged just 2 grams per day, while young adults consumed an average of 4 grams per day.
This research adds to a growing body of evidence supporting the health benefits of walnuts. A study conducted last year indicated that regular walnut consumption could improve cognitive development in adolescents with Attention Deficit Hyperactivity Disorder (ADHD). Furthermore, walnuts have been shown to positively influence heart health by stimulating the body’s natural production of the amino acid L-homoarginine, which plays a role in cardiovascular function.
In conclusion, while more research is needed to fully understand the relationship between walnut consumption and obesity, particularly in young women, these findings suggest that incorporating walnuts into a balanced diet could be a valuable strategy for promoting healthy weight management and overall well-being.
Read MoreOne-third of NHS diet programme participants achieve type 2 diabetes remission, study finds
A recent study published in The Lancet Diabetes & Endocrinology has revealed that approximately one-third of participants in the National Health Service (NHS) shakes and soups diet programme in England have achieved remission from type 2 diabetes. This study, which evaluated the effectiveness of total dietary replacement (TDR) for insulin-independent diabetes remission, sheds light on the potential of structured diet interventions in managing type 2 diabetes on a large scale.
The escalating rates of diabetes in the United Kingdom have led the NHS to implement the Type 2 Diabetes Path to Remission (T2DR) initiative. This programme is centred around a low-calorie, micronutrient-rich diet, which has been shown to result in significant weight loss and sustained remission of diabetes. While clinical trials have demonstrated the efficacy of such dietary interventions, their effectiveness in broader, real-world contexts has remained unclear until now.
The T2DR programme is designed to help individuals lose weight, maintain that weight loss, and reduce their reliance on glucose-lowering medications. The programme comprises 20 sessions divided into three phases: the TDR phase, the food reintroduction phase, and the weight maintenance phase. The TDR phase, lasting 12 weeks, focuses on strict calorie intake regulation accompanied by coaching. Following this, the food reintroduction phase spans 4 to 6 weeks, during which participants are guided on healthy eating habits and goal-setting. The final phase, weight maintenance, involves monthly coaching sessions aimed at behaviour modification and encouraging physical activity to help participants sustain their weight loss and health improvements.
This study utilised prospective, national-level data to assess whether the NHS’s T2DR programme effectively promotes remission of type 2 diabetes. Researchers analysed data from English adults aged between 18 and 65 who had been diagnosed with type 2 diabetes within the previous six years and were referred to the T2DR programme by their general practitioners between September 2020 and December 2022. Participants included in the study had a body mass index (BMI) of at least 27 kg/m² for white individuals, with a lower threshold of 25 kg/m² for individuals of other ethnicities.
To determine the programme’s effectiveness, the researchers linked programme data with records from the National Diabetes Audit (NDA). They specifically examined glycated haemoglobin (HbA1c) levels and the use of oral hypoglycaemic medications. Eligible participants had recent HbA1c levels ranging from 43 to 87 mmol/mol if they were on glucose-lowering medications, or 48 to 87 mmol/mol if they were not.
The primary outcome of the study was diabetes remission at one year, defined by two HbA1c readings below 48 mmol/mol taken at least three months apart, without the use of glucose-lowering medications. These readings were collected from three months before the initial HbA1c measurement up to 15 months later. Secondary outcomes included the absolute and percentage changes in body weight, as well as the proportion of participants achieving at least 10% and 15% weight loss within one year.
The study focused on participants who began the TDR-based programme before 2022 and had completed it by December 2022, which included having their body weight recorded at the one-year mark. Researchers employed multivariate regression analyses to account for various factors, including demographic characteristics (age, gender, socioeconomic status, and ethnicity), clinical variables (duration of diabetes, baseline BMI, and HbA1c levels), and details about the programme’s delivery method and provider. Sensitivity analyses were also conducted to evaluate different timings for subsequent HbA1c measurements, ranging from 11 to 15 months after the initial reading.
Between September 2020 and December 2022, a total of 7,540 individuals were referred to the T2DR programme. The average age of participants was 50 years, with 43% being male and 64% identifying as white. Of these, 1,740 individuals initiated the TDR phase before 2022, with the aim of completing the programme within one year. Among those who started the programme before 2022, 55% (960 individuals) successfully completed it.
Out of all participants referred to the programme, 34% were not taking glucose-lowering medications, 50% were on one medication, and 16% were on two or more, with metformin being the most commonly prescribed.
The mean weight loss among the 1,710 participants who started the programme before 2022 was 9.40 kg, or 8.3% of their initial body weight. For the 945 participants who completed the programme, the average weight loss increased to 10 kg, or 9.3% of their starting weight. Among those with at least two HbA1c readings, 27% (190 individuals) achieved diabetes remission, with an average weight loss of 15 kg, or 13%. Of the 945 individuals who completed the programme, 48% (450 participants) had two HbA1c readings available, and of these, 32% (145 individuals) achieved remission, with an average weight loss of 16 kg, or 14%.
Furthermore, 42% of the 945 individuals who completed the programme lost at least 10% of their baseline weight, and 20% lost at least 15%. Among those who achieved remission, 76% (110 participants) lost at least 10% of their baseline weight, and 45% (65 participants) lost at least 15%. Sensitivity analyses produced consistent results, reinforcing the findings.
The study concluded that 27% of participants in the NHS T2DR programme achieved diabetes remission, demonstrating that remission is possible outside of controlled research settings with widespread implementation. However, remission rates in real-world applications are lower, and data collection is more limited compared to randomised controlled trials. These findings are significant as they provide valuable insights for policymakers regarding the operational effectiveness of the TDR approach and its potential impact on public health.
Read MoreExploring the role of the Mediterranean diet in mitigating gestational diabetes risk
A recent comprehensive study published in the journal Nutrition & Diabetes delves into the potential impact of the Mediterranean diet (MedDiet) on reducing the incidence of gestational diabetes mellitus (GDM), a prevalent complication during pregnancy characterised by impaired insulin utilisation due to placental hormones.
GDM not only poses immediate health risks to both mother and child during pregnancy, including heightened risk of birth complications and future chronic conditions, but also contributes to longer-term health issues. Consequently, managing blood glucose levels through medical and dietary measures is essential.
Prevailing research underscores the efficacy of dietary and lifestyle changes in the early stages of pregnancy, or even prior, in averting GDM. Diets high in saturated fats, cholesterol, carbohydrates, and total fats are typically linked to a higher GDM risk.
The Mediterranean diet is noted for its emphasis on whole grains, vegetables, legumes, and foods high in monounsaturated fatty acids (MUFAs), while limiting processed and red meats. Instead of isolating individual dietary components, assessing overall dietary patterns like the MedDiet may offer a holistic approach to managing or preventing GDM.
Numerous studies corroborate that a strict adherence to the MedDiet correlates with a reduced risk of GDM. However, a systematic review and meta-analysis are crucial to consolidate these findings comprehensively.
The current review collated studies up to August 2023 from databases such as PubMed, Web of Science, Google Scholar, and Scopus, excluding duplicates, animal studies, ecological studies, short communications, and non-English articles.
From the selected studies—two case-control and eight cohort studies—conducted in diverse locations including the USA, various Mediterranean countries, Australia, Iran, Spain, and Greece, researchers analysed data from over 32 million participants aged 18 to 45.
The Mediterranean Diet Adherence Screener (MEDAS) score, higher quartiles of alternate MED (AMED) score, and the Mediterranean-Style Dietary Pattern Score (MSDPS) were tools used to assess dietary adherence. GDM outcomes were evaluated using criteria from the National Diabetes Data Group, and through fasting or postprandial blood sugar levels, or glucose challenge tests.
Findings from seven out of ten studies reviewed demonstrated a significant link between higher MedDiet adherence and lower GDM risk, although results varied due to differences in study designs or dietary assessment periods.
Interestingly, while case-control studies reported a substantial 75% reduction in GDM risk among women with higher MedDiet adherence, cohort studies indicated a more moderate 20% risk reduction. The larger reductions noted in case-control studies might stem from recall biases, possibly exaggerating the risk reduction.
Subgroup analyses showed that the benefits of MedDiet adherence in reducing GDM risk applied across both Mediterranean and non-Mediterranean populations, suggesting universal applicability of this dietary pattern.
Higher consumption of whole grains, fruits, vegetables, extra virgin olive oil, nuts, and legumes, alongside regular fish and seafood intake, characterises greater adherence to the MedDiet. This diet, rich in antioxidants and vitamins, mitigates oxidative stress and inflammation, critical factors in chronic disease progression.
The diet’s high polyphenol content in fruits and vegetables plays multiple roles in reducing GDM risk, including glucose absorption inhibition in the gastrointestinal tract, anti-inflammatory properties, microbiota modification, and enhanced antioxidant capacity.
Previous meta-analyses have linked greater MedDiet adherence to reduced obesity or overweight risks by 9%, noting that obesity and insulin resistance are significant GDM risk factors. Additionally, whole grains and nuts, rich in MUFAs and polyunsaturated fatty acids (PUFAs), help regulate blood glucose levels and control appetite.
Observational studies have suggested that long-term red meat consumption may increase GDM risk, further supporting the reduced GDM incidence among those adhering to the MedDiet.
The current systematic review and meta-analysis provide strong evidence supporting the MedDiet’s role in reducing GDM risk when followed before or during pregnancy. It is advisable for women of reproductive age to consider the MedDiet to prevent GDM and other adverse pregnancy outcomes.
Further research should explore the interaction between the MedDiet, genetic factors, and lifestyle elements to refine preventive strategies for GDM.
Read MoreNutritional studies highlight pulses as key to lowering diabetes and cholesterol risks
Research consistently highlights pulses—such as beans, peas, lentils, and chickpeas—as crucial allies in the fight against diabetes and elevated cholesterol levels. This insight comes at a critical time, as projections from a study published in The Lancet last year forecast that diabetes could affect over 1.31 billion people globally by 2050. Concurrently, elevated cholesterol levels remain a significant health issue, with nearly half of adults in the UK exceeding national guidelines.
A detailed review in the journal Nutrients has shown that regular consumption of pulses can significantly improve these concerning health trends. The review meticulously examined thirty studies that looked at various types of pulses, including lentils, chickpeas, and several common beans like pinto, black, and kidney beans. The studies covered a wide array of health outcomes, from lipid profiles and blood pressure to risks of cardiovascular diseases and diabetes management.
The findings from these studies are telling. They specifically note improvements in low-density lipoprotein (LDL) and high-density lipoprotein (HDL) cholesterol, systolic and diastolic blood pressure, fasting blood sugar, haemoglobin A1c levels, waist circumference, and markers of inflammation and sensitivity such as C-reactive protein. These outcomes particularly underscore the potential of pulses to enhance lipid profiles and manage blood pressure.
The review emphasised that interventional studies, which typically have larger sample sizes and provide robust data, consistently confirm the health benefits of pulses. These studies often involved dietary adjustments where pulses replaced red meat or were added to diets as fixed servings. The results repeatedly demonstrated improvements in dietary quality and beneficial health outcomes.
Pulses’ potential to prevent heart disease is particularly noteworthy, largely due to their ability to lower total and LDL cholesterol levels. The authors of the review highlight that pulses are low in fat and rich in healthy mono- and polyunsaturated fats, essential micronutrients, and bioactive compounds with antioxidant properties, making them a true “nutritional powerhouse.”
Longitudinal studies also link higher pulse consumption with reduced risks of developing type 2 diabetes. This association is bolstered by interventional studies that document notable improvements in fasting glucose levels and insulin sensitivity with increased pulse intake. Consequently, pulses are not only pivotal in preventing diabetes but also in managing blood glucose levels effectively.
Tim McGreevy, CEO of USA Pulses, commented on the research, stating, “This research accentuates the fact that pulses are beneficial for health in so many ways, underscoring dietary guidelines that endorse plant-based eating patterns,” even though he was not directly involved in the study.
Additionally, awareness about type 2 diabetes is critical as many individuals may be unknowingly afflicted. Symptoms to watch for include increased urination, persistent thirst, excessive tiredness, unexplained weight loss, genital itching or recurrent thrush, delayed healing of wounds, and blurred vision. Recognising these signs can prompt earlier intervention and management of the condition, further reducing long-term health risks.
Read MoreNew research highlights the obesity-fighting properties of the ketogenic diet
A groundbreaking study recently published in Nature Metabolism has uncovered the protective effects of bile acids (BAs) induced by the ketogenic diet (KD) in the fight against obesity.
Obesity is linked to a myriad of health issues including cardiovascular diseases, cancer, diabetes, and non-alcoholic fatty liver disease. These associations underscore the urgent need for effective treatments to alleviate its extensive health impacts.
The ketogenic diet, recognised for its distinctive metabolic effects, has been proven beneficial in managing refractory epilepsy and other health disorders. Research indicates that changes in gut microbiota and metabolites might play a role in the diet’s protective properties against intestinal inflammation and seizures.
Although it’s clear that gut microbiota and metabolites are pivotal in the metabolic transformations elicited by KD in both rodents and humans, the specific microbes and metabolites responsible remain unidentified.
In the referenced study, the efficacy of KD in obesity prevention was demonstrated through an experimental setup involving mice. These mice were fed either a standard chow diet (CD) or a KD for seven weeks. Results indicated significant reductions in fasting glucose levels and body weight in those on KD. Metabolomics analysis further identified shifts in the metabolic profiles of the KD group, with increases in 22 metabolites and decreases in 18.
A subsequent experiment involved feeding mice with CD, KD, or a methionine-supplemented version of KD (KDM) over seven weeks. The addition of methionine to KD reversed the diet’s reductions in glucose levels and body weight and decreased six taurine-conjugated bile acids in serum. KD alone reduced levels of certain unconjugated BAs, which were restored by KDM.
When gut microbiota were depleted, differences in body weight and glucose levels between KD and KDM groups vanished, highlighting the role of microbiota in these effects. Faecal microbiota transplantation (FMT) from KD-fed to CD-fed mice resulted in weight loss and enhanced glucose tolerance. Conversely, FMT from KDM mice had no significant impact.
Further analyses showed that KD reduced the alpha diversity of gut microbiota, a change reversed by KDM. This diet also affected specific bacterial strains, which were restored by KDM supplementation. Studies on energy absorption revealed that KD-fed mice exhibited higher faecal energy content, suggesting a reduction in calorie absorption.
RNA sequencing of ileal tissues indicated that treatment with specific bile acids (TUDCA or TDCA) downregulated CAR1, a gene associated with obesity. These treatments also diminished lipid accumulation in cells, facilitated weight loss, and decreased intestinal lipid absorption in mice.
In models of diabetes and obesity, treatments with TUDCA and TDCA resulted in weight reduction, lower fasting glucose levels, improved glucose tolerance, and decreased liver fat. Human studies paralleled these findings, showing that lower plasma levels of certain conjugated BAs were associated with higher body mass index and fasting glucose levels.
In conclusion, this study illuminates the potential of the ketogenic diet and targeted bile acid treatments in managing obesity and improving metabolic health through modifications in gut microbiota and metabolic processes.
The findings highlight critical host-gut microbiota interactions and support the use of TUDCA and TDCA as potential therapeutic agents for tackling obesity and its associated complications.
Read MoreNatural compound found in olives shown to lower blood sugar and aid weight loss, mouse study shows
A novel study conducted using mice models has highlighted the potential of elenolic acid, a natural compound extracted from olives, in mitigating obesity and type 2 diabetes. This groundbreaking research suggests that elenolic acid could serve as a basis for the development of affordable, safe natural products aimed at managing these prevalent health issues.
In a series of experiments, diabetic mice with obesity administered with elenolic acid orally displayed a significant reduction in body weight and enhanced glucose regulation within just one week. These results were noteworthy when compared to a control group of mice with obesity that did not receive the treatment. Remarkably, the glucose-lowering impact of elenolic acid was on par with liraglutide, an injectable diabetes medication, and surpassed the effectiveness of metformin, a commonly used oral diabetes drug.
Professor Dongmin Liu, the lead researcher and a professor at the Department of Human Nutrition, Foods and Exercise at Virginia Tech, explained the motivation behind their focus on natural compounds. “Lifestyle modifications and public health measures have had limited impact on the rising prevalence of obesity, one of the top risk factors for type 2 diabetes. Available obesity drugs are ineffective in weight loss maintenance, expensive and/or carry potential long-term safety risks. Our goal was to develop safer, cheaper and more convenient multi-targeting agents that can prevent the occurrence of metabolic disorders and type 2 diabetes,” stated Liu.
The research findings will be presented by Dr. Hana Alkhalidy, a scientist in Liu’s laboratory, at NUTRITION 2024, the premier annual event of the American Society for Nutrition.
The team at Virginia Tech has previously investigated various natural compounds targeting molecular aspects of metabolism in critical body parts like the pancreas, muscle, fat tissues, and liver. Their latest strategy focuses on stimulating hormone secretion in the gut, a method that could indirectly improve metabolic functions due to natural products’ generally poor bioavailability.
Their screening identified that elenolic acid, found abundantly in mature olives and extra virgin olive oil, stimulates the release of metabolic hormones GLP-1 and PYY in the gut. These hormones are integral during meals, enhancing satiety and regulating blood sugar and metabolism. The researchers synthesized elenolic acid from its precursor, oleuropein, which proved to be a cost-effective method compared to direct extraction from olives.
Further testing revealed that diabetic mice with obesity treated with elenolic acid for four to five weeks showed a 10.7% reduction in obesity and exhibited glucose levels and insulin sensitivity comparable to healthy, lean mice. Additionally, the treatment significantly curbed food intake and fostered weight loss, effects associated with increased levels of PYY and GLP-1 and decreased expression of agouti-related peptide, a hypothalamic peptide that promotes overeating and weight gain when overexpressed.
“Overall, the study showed that elenolic acid from olives has promising effects on hormone release and metabolic health, particularly in obese and diabetic conditions,” Liu remarked. He noted that the compound mimics the physiological conditions of eating to enhance gut metabolic hormone secretion, thereby helping to regulate energy balance and metabolic health.
Despite these promising results, the researchers cautioned that the concentration of elenolic acid in typical olive products is quite low, implying that the health benefits observed in the study are unlikely to be replicated through consumption of olives and olive oil alone.
The research team is now focused on elucidating the metabolic pathway of elenolic acid, from its absorption to its excretion. This exploration will provide further insights into the compound’s efficacy and safety, paving the way for potential clinical trials.
Read More