Obesity Care

Greater fruit intake linked to lower abdominal fat in US children, study finds

Key Takeaways: 

• A nationally representative study of over 1,700 children in the United States found that higher fruit consumption is significantly associated with lower levels of abdominal adiposity.
• Children who consumed moderate to high amounts of fruit had smaller waist circumferences and reduced abdominal height, especially among boys and those with healthier lifestyle habits.
• The findings suggest fruit’s low energy density and high fibre content may be key contributors to improved weight outcomes, although causality cannot be established due to the study’s cross-sectional design.
  

Introduction

A new study led by Professor Larry A. Tucker of Brigham Young University, published in Frontiers in Nutrition, has identified a significant association between fruit intake and abdominal adiposity among children in the United States. The research highlights the potential role of fruit consumption in addressing paediatric obesity, particularly abdominal fat accumulation, which is a known risk factor for numerous metabolic diseases.

Context: The Obesity Crisis in Children

Childhood overweight and obesity remain a pressing public health concern in the United States, currently affecting over 40% of children. The prevalence of these conditions has increased nearly fivefold in the past half-century among children and adolescents.

Excess body weight during childhood increases the risk of a wide range of physical and psychological health problems, including:

• Insulin resistance and type 2 diabetes
• High blood pressure and cholesterol levels
• Cardiovascular disease
• Depression and anxiety

Although Body Mass Index (BMI) is commonly used to assess weight status, it does not distinguish between fat and lean mass, nor does it indicate where fat is distributed. This is a critical limitation, as abdominal adiposity – excess fat around the midsection – has been shown to be more predictive of cardiometabolic risk than BMI alone.

According to the Lancet Diabetes & Endocrinology Commission, waist circumference and other measures of central adiposity should be prioritised in research and clinical assessments. The accumulation of abdominal fat is especially influenced by dietary patterns, including the consumption of high-energy-dense foods, which are typically high in fat and low in water and fibre.

Why Fruit Matters

Fruits are among the lowest energy-dense food groups, thanks to their high water and fibre content and minimal fat. Numerous studies have indicated that diets rich in fruits and other low-energy-dense foods are effective in supporting healthy body weight.

Given these properties, this study sought to examine whether there is a measurable association between fruit intake and abdominal fat among a nationally representative sample of children aged 8 to 11 years in the United States.

Study Design and Methodology

The research analysed data from 1,707 children enrolled in the National Health and Nutrition Examination Survey (NHANES), a population-based study conducted by the US National Center for Health Statistics (NCHS) and the Centers for Disease Control and Prevention (CDC).

Key measurements and parameters included:

• Fruit intake: Assessed using two 24-hour dietary recall interviews. Fruit juices were excluded. Intake was calculated as the percentage of total daily energy derived from fruit.
• Abdominal adiposity: Measured using waist circumference and sagittal abdominal diameter (also known as abdominal height).
• Confounding variables: Adjusted for age, sex, race, household size, survey year, physical activity, recreational computer use, total energy intake, and consumption of macronutrients (carbohydrates, protein, fat), sugar, saturated fat, and fibre.

Results and Observations

Fruit Consumption Patterns

• 27% of children reported consuming no fruit at all.
• 36% consumed a low amount of fruit.
• 37% consumed a moderate-to-high amount of fruit.
• On average, fruit made up 10% of total energy intake.

Association with Abdominal Fat

After accounting for confounding factors, the study found that:

• Children who consumed more fruit had significantly smaller waist circumferences and lower sagittal abdominal diameters.
• The association was stronger and statistically significant for sagittal abdominal diameter.
• For waist circumference, the association was marginally significant in the fully adjusted model.
  

Lifestyle Factors Matter

Subgroup analyses revealed that the benefits of fruit intake were more pronounced among children who:

• Engaged in at least one hour of physical activity on four or more days per week.
• Spent two hours or less per day on recreational computer use.
  

Among children who were less active or had higher screen time (three hours or more per day), the association between fruit intake and abdominal adiposity was not significant.

Nutritional Insights

Children with higher fruit intake were found to consume:

• Greater amounts of dietary fibre, natural sugars, and carbohydrates.
• Lower levels of saturated fat.
  

These dietary patterns are consistent with the properties of fruit as a low-energy-dense food. Fibre, in particular, may help explain the association with lower abdominal fat, as it contributes to satiety, regulates gut microbiota, and has been shown to support metabolic health.

Fruits are also rich in micronutrients and bioactive compounds, including:

• Vitamins
• Antioxidants
• Flavonoids
• Phytochemicals

These compounds are known to reduce inflammation, improve insulin sensitivity, and regulate hunger-related hormones such as leptin and ghrelin – all of which may support healthy weight management.

Public Health Implications

Despite the benefits highlighted in this study, approximately 80% of the US population fails to meet the recommended daily fruit intake outlined in the 2020–2025 Dietary Guidelines for Americans. Professor Tucker commented:

“Fruit intake is widely underconsumed in the United States. These findings support the view that fruit can play a crucial role in the prevention of abdominal obesity in children.”

He urged healthcare professionals, parents, and educators to encourage fruit consumption as part of broader efforts to combat paediatric obesity and its associated health complications.

Limitations and Future Research

While the study presents compelling evidence of an association between fruit intake and reduced abdominal fat, its cross-sectional design limits the ability to establish causality. Longitudinal or experimental studies would be necessary to confirm whether increasing fruit consumption directly leads to reduced abdominal adiposity.

Additionally, the NHANES methodology involves oversampling certain ethnic groups, such as Mexican Americans, which may have influenced the racial distribution of the study population.

Conclusion

This study contributes to a growing body of evidence suggesting that fruit consumption supports healthier body composition in children. With paediatric obesity continuing to rise, particularly in the United States, promoting higher fruit intake may offer a simple, evidence-informed strategy for reducing central fat accumulation and associated health risks in young people.

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Global study provides practical guidance on antibiotic dosing for people with obesity

Key Takeaways: 

• A major systematic review has revealed how obesity alters the distribution and efficacy of antibiotics, with significant implications for dosing and therapeutic outcomes.
• While certain antibiotics such as β-lactams may not require routine adjustments, classes like aminoglycosides and glycopeptides require close monitoring and individualised dosing.
• The research team calls for global data sharing and improved pharmacokinetic studies to inform evidence-based dosing guidelines.
  

Introduction: A Call for Precision in Dosing

A large international team of researchers has published the most comprehensive analysis to date on antibiotic dosing in people living with obesity. Led by Dr Anne-Grete Märtson of Leiden University and Dr Thomas Tängdén of Uppsala University, the review brings together findings from 128 studies and proposes practical recommendations for clinical dosing adjustments. The work, published in The Lancet Infectious Diseases on 15 May, represents a significant step towards individualised antibiotic therapy in a population often overlooked in clinical pharmacology.

“It’s high time researchers started sharing more data,” said Märtson, underscoring the pressing need for greater collaboration to close longstanding gaps in clinical guidance.

Clinical Foundations and Rising Challenges

Märtson’s interest in the topic was informed by her early career as a clinical pharmacist in Estonia, where she participated in hospital ward rounds and focused on drug safety and dosing. “As a clinical pharmacist, I focused on the medication: was a certain combination of drugs safe, what was the optimal dose?”

Today, with rising obesity rates globally, clinicians are increasingly encountering challenges in treating infections effectively. “We’re increasingly seeing limited responses to administered medicines – in some patients the infection even worsens,” she noted. Complicating matters, most drug labels do not include dosing guidance for people with obesity, leaving clinicians without clear direction.

How Obesity Affects Antibiotic Pharmacokinetics

The review explains that obesity can significantly influence how antibiotics are absorbed, distributed, and cleared from the body. Changes in body composition, such as increased fat and muscle mass, and potential organ dysfunction, especially of the liver or kidneys, can affect the volume of distribution and drug metabolism.

“Substantial changes can occur in the volume of distribution due to increased fat and muscle mass, and tissue drug concentrations might be lowered,” the authors write.

Mahyar Etminan, a drug safety epidemiologist with EpiLytics Consulting who was not involved in the study, commented that “you need more of the drug to get into the tissue and that usually means higher doses than what we usually use in non-obese patients.” He also advised choosing antibiotics with higher tissue penetration.

128 Studies Analysed Across Multiple Drug Classes

Märtson and her colleagues systematically reviewed over 6,000 studies, narrowing their analysis to 128 that met strict inclusion criteria. Of these, 57 focused on β-lactam antibiotics, while 45 examined glycopeptides, lipoglycopeptides, and oxazolidinones. The analysis covered individuals aged 18 years and older with a Body Mass Index (BMI) over 30.

The findings showed that commonly prescribed antibiotics for pneumonia, urinary tract infections, and other bacterial conditions behave differently in people with obesity. “They distribute differently across the body’s tissues. Sometimes too little reaches the lungs, even though you’re trying to treat a lung infection,” Märtson explained.

Recommendations by Antibiotic Class

The review provides tailored guidance for specific classes of antibiotics:

β-lactams

This broad class, which includes penicillins and cephalosporins, is widely used for acute infections. Although obesity modestly alters their pharmacokinetics, the review concludes:

“Obesity modestly alters the pharmacokinetics of β-lactam antibiotics, but evidence does not support routine dose adjustments.”

However, it cautions against overly aggressive dosing due to the risk of toxic concentrations and side effects.

Aminoglycosides and Glycopeptides

These antibiotics are used for severe infections and require careful dose management.

“Therapeutic drug monitoring and the monitoring of creatinine clearance are highly recommended to guide maintenance dosing,” the authors state.

For aminoglycosides in particular, standard practice already includes therapeutic drug monitoring due to risks of nephrotoxicity and irreversible hearing damage. Dosing based on adjusted body weight is recommended to avoid under- or overdosing.

Other Antibiotic Classes

The study found that not all antibiotics require specific adjustments. In some cases, the pharmacological properties of the drug mean standard doses may remain appropriate, though further studies are needed to confirm this across more antibiotic types.

Optimising Dosing in Critical Care Settings

Märtson highlighted practical clinical strategies such as modifying infusion duration. “In critically ill patients, it can be helpful to administer the dose over two to four hours instead of half an hour via infusion,” she noted, emphasising the need to maintain appropriate plasma concentrations for effective treatment.

Gaps in the Data and the Need for Shared Research

Despite these insights, the researchers emphasise that much of the existing evidence remains limited. Many included studies were small-scale, and more robust pharmacokinetic data are needed. “There are excellent methods available to conduct high-quality research into this issue,” said Märtson, referencing tools like CT imaging to assess body composition and predictive modelling using large datasets.

The authors stress that:

“In the absence of robust pharmacokinetic data to inform dose adjustments, therapeutic drug monitoring can be useful to guide individualised dosing.”

They also call on future research to account for variables such as infection site, severity of illness, pathogen susceptibility, and potential drug toxicity when considering dosage in people with obesity.

Conclusion: Towards Evidence-Based Personalised Antibiotic Dosing

Märtson, Tängdén, and their multinational team – including contributors from the United States, Belgium, Austria, Germany, and Australia – have laid a critical foundation for improving antibiotic treatment in people with obesity. Their systematic review offers both immediate clinical value and a roadmap for future research.

As Märtson concluded, “I hope researchers will start sharing more data, so we can ultimately establish proper guidelines for all antibiotics.”

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Low-calorie diets linked to increased risk of depression, especially in men and people living with obesity

Key Takeaways: 

• Low-calorie diets may increase the risk of depressive symptoms, particularly among men and people living with overweight or obesity, according to a large population study.
• Nutritional deficiencies linked to unsupervised calorie restriction may negatively affect mental wellbeing, highlighting the importance of dietary quality.
• The findings challenge previous clinical studies suggesting mood benefits from calorie restriction, calling attention to the gap between controlled interventions and real-world dieting behaviour.
  

Introduction

Restrictive dieting is a common approach to weight management, but emerging evidence suggests that cutting calories—especially without professional guidance—may have unintended consequences for mental health. A new Canadian study published in BMJ Nutrition, Prevention & Health has found a link between low-calorie diets and an increased risk of depressive symptoms, particularly among men and individuals living with overweight or obesity.

Study Overview

Researchers analysed data from 28,525 adults who took part in the US National Health and Nutrition Examination Survey (NHANES). Participants completed a standardised mental health questionnaire, which assessed symptoms such as persistent low mood, fatigue, and disturbed sleep.

The study revealed that individuals who were actively restricting their calorie intake scored higher for depressive symptoms than those who were not dieting. The association was especially pronounced among:

• Men
• People classified as having overweight or obesity

Overall, around 8% of participants reported symptoms of depression, while over 70% were living with overweight or obesity—a demographic more likely to engage in calorie-restrictive dieting.

The Role of Nutritional Deficiency

While the study could not prove causation, the researchers proposed that self-imposed dietary restrictions may lead to insufficient intake of essential nutrients—particularly protein, vitamins, and minerals. Such deficiencies can place the body under physiological stress, potentially exacerbating or triggering symptoms of poor mental health.

This stands in contrast to earlier clinical trials where calorie-restricted diets appeared to improve mood. However, the authors of the current study point out that these prior interventions were typically nutritionally balanced and closely monitored, unlike the unsupervised and potentially imbalanced dieting patterns seen in the general population.

Diet Quality Matters

The study draws a distinction between restrictive dieting and overall dietary quality. Diets that are rich in whole foods—including fruits, vegetables, whole grains, nuts, and lean protein—have consistently been associated with lower rates of depression. In contrast, those high in ultra-processed foods and refined carbohydrates are linked to higher depression risk.

Expert Commentary

Professor Sumantra Ray, Executive Director of the NNEdPro Global Institute for Food, Nutrition and Health, underscored the wider implications of the findings:

“This adds to the growing body of evidence linking diet and mental health.

Restrictive diets low in nutrients important for cognitive function, such as omega-3 and vitamin B12, may contribute to depressive symptoms. However, further well-designed studies are needed to better understand these relationships.”

Implications for Healthcare Practice

While the study is observational and cannot confirm a causal relationship, it offers a timely reminder for healthcare professionals. When supporting individuals who wish to lose weight, especially those with existing vulnerabilities to depression or anxiety, it is crucial to:

• Emphasise nutritional adequacy, not just calorie reduction
• Support patients in choosing sustainable, balanced dietary patterns
• Consider mental health screening as part of weight management strategies

In summary, the findings call for a more nuanced approach to dietary advice—one that respects the complex interplay between physical and mental health, and avoids simplistic calorie-cutting recommendations that may do more harm than good.

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Shedding excess weight in midlife may protect against chronic illness and early death, study finds

Key Takeaways:

• Adults who reduced their weight from overweight to a healthy range in midlife—without medication or surgery—experienced significantly lower risks of chronic disease and death.
• These health benefits extended beyond the reduced risk of type 2 diabetes and were evident even decades later.
• Sustained, intentional weight loss through lifestyle changes may offer long-term protective effects, especially when initiated between the ages of 40 and 50.

Introduction

A new study published in JAMA Network Open has provided compelling evidence that sustained weight loss during midlife can significantly reduce the long-term risk of chronic illness and premature death. While pharmacological treatments such as GLP-1 receptor agonists and bariatric surgery are effective in promoting weight loss, they carry inherent risks. This research focuses on the long-term outcomes of weight loss achieved without these medical or surgical interventions.

Obesity is a well-established risk factor for several chronic conditions, particularly type 2 diabetes. However, the long-term health outcomes associated with lifestyle-induced weight loss—outside of diabetes risk—remain less well understood. This study aimed to clarify these outcomes by examining the health trajectories of individuals aged 40 to 50 who achieved and maintained weight loss over multiple decades.

Study Overview

The analysis drew upon data from 23,149 adults enrolled in three long-running cohort studies:

• Whitehall II Study (WHII) (1985–1988, United Kingdom)
• Helsinki Businessmen Study (HBS) (1964–1973, Finland)
• Finnish Public Sector Study (FPS) (2000, Finland)

Participants’ body mass index (BMI) was measured repeatedly over periods ranging from 12 to 35 years. Individuals were then categorised into four groups based on their BMI trajectories:

1. Persistent healthy weight (BMI consistently <25)
2. Weight loss (BMI reduced from ≥25 to <25)
3. Weight gain (BMI increased from <25 to ≥25)
4. Persistent overweight (BMI consistently ≥25)

The study excluded individuals who used medications or underwent surgery for weight loss, focusing solely on lifestyle-driven changes. Furthermore, participants were initially free from diagnosed chronic disease, limiting the likelihood of confounding due to weight loss caused by illness.

Key Findings

Risk of Chronic Disease

Participants who moved from an overweight to a healthy weight category and sustained this reduction experienced significantly lower risks of chronic disease. Notably:

• In the WHII cohort, individuals who lost weight or maintained a healthy BMI were 50% less likely to develop one or more chronic conditions over a median follow-up of 23 years, compared to those who remained overweight.
• After adjusting for the effects of reduced type 2 diabetes risk, the chronic disease risk remained 40% lower, suggesting additional health benefits.
• In the FPS cohort, weight loss was associated with a 60% reduction in chronic disease risk over a 12-year median follow-up.

These reductions were accompanied by healthier clinical profiles, such as lower mean blood pressure and total cholesterol levels among those who lost weight.

Mortality Risk

In the HBS cohort, participants who achieved a healthy weight had a 20% lower risk of death over 35 years. The median age at death in this cohort was 91, highlighting the extended timeline over which benefits may be realised.

Weight Gain and Health Risk

Individuals who moved from a healthy BMI into the overweight category had a higher risk of developing chronic disease than those who maintained a healthy weight. However, their risk was still lower than those who were persistently overweight.

Methodological Strengths and Considerations

A key strength of this study is its ability to exclude confounding by unintentional weight loss—a marker often associated with disease, frailty, or undiagnosed cancer—by selecting relatively young, healthy participants. This helps to isolate the effects of deliberate, lifestyle-induced weight loss.

The findings also contrast with previous studies that assessed weight loss through medication or surgery. While such treatments result in more dramatic weight changes, the long-term benefits—especially on cardiovascular health or mortality—have remained inconsistent. This may partly reflect the concurrent use of medications such as statins in control groups or short follow-up periods.

Importantly, the study did not specifically verify whether the observed weight loss was intentional. However, the researchers argued that, given the health status and age of the participants, it was reasonable to assume the changes were deliberate and achieved through modifications in diet, physical activity, or other lifestyle factors.

The FPS cohort relied on self-reported weight and height, which introduces a potential for reporting bias. In contrast, the WHII and HBS cohorts used measured BMI values, lending stronger credibility to their findings.

Implications for Practice and Public Health

This study provides robust evidence that moderate, sustained weight loss during midlife can have enduring health benefits, even when achieved without pharmacological support. Importantly, these benefits extend beyond the well-documented reductions in type 2 diabetes risk to include decreased risks of other chronic diseases and premature mortality.

Furthermore, the results reinforce the value of early intervention. Reducing weight in one’s 40s or early 50s appears to change the trajectory of long-term health outcomes, with positive effects that may take decades to fully manifest.

The findings also highlight a public health challenge: while people living with severe obesity may require pharmacotherapy or surgery, many individuals with moderate overweight status may significantly benefit from supported lifestyle changes. These results suggest that weight management efforts should be actively promoted and supported at midlife to yield maximum long-term impact.

Conclusion

The study found that individuals who transitioned from an overweight BMI to a healthy range during midlife—without the aid of weight loss medications or surgery—experienced a significantly lower risk of chronic disease and, in some cases, reduced all-cause mortality. These findings underscore the potential of midlife lifestyle changes to yield meaningful and sustained health benefits well into older age.

As the global burden of overweight and obesity continues to rise, these insights serve as a call to action for healthcare providers and public health authorities to support early, intentional weight management through non-pharmacological means whenever possible.

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Maternal obesity linked to increased risk of infection-related hospital admissions in children, study finds

Key Takeaways:

• Children born to people with obesity (BMI ≥35) face a significantly increased risk of hospital admission for infections up to age 15.
• The risk is most pronounced during infancy and again between ages 5 and 15, with respiratory, gastrointestinal, and viral infections driving most admissions.
• Caesarean delivery and child obesity in early years appear to partly explain the association, suggesting potential areas for public health intervention.

Introduction

A long-term UK study published in BMJ Medicine has found that children born to women with obesity—specifically those with a body mass index (BMI) of 35 or above—are at an elevated risk of hospitalisation due to infections. The study, based on nearly 10,000 births in Bradford, England, highlights how maternal health before and during pregnancy can have long-lasting implications for child health, particularly regarding immune-related outcomes.

Global and Biological Context

Researchers emphasise that maternal obesity is a growing global health issue, with estimates suggesting it could affect nearly 1 in 4 pregnancies worldwide by 2030. Obesity is marked by chronic low-grade inflammation, which is associated with a range of biological changes—disruption of immune function, alterations in gene expression, and changes to the gut microbiome—all of which may influence foetal development and subsequent childhood health.

While past studies have investigated the potential link between maternal obesity and childhood infections, findings have been inconsistent. Furthermore, it has remained unclear whether modifiable factors such as breastfeeding, method of delivery, and pregnancy-related weight gain might influence this relationship.

Study Design and Population

To explore these questions, researchers analysed data from the Born in Bradford study, a prospective birth cohort that investigates how social, environmental, and genetic factors affect maternal and child health over time.

The analysis included 9,037 women who gave birth to a live infant at Bradford Royal Infirmary between March 2007 and December 2010 and for whom both height and weight data were available. Of these participants:

• 45% were of Pakistani origin,
• 40% were white British, and
• 37% lived in the most socioeconomically deprived areas of the UK.

In total, 9,540 children were followed for health outcomes—specifically hospital admissions for infections—from birth until October 2022, or until the child either withdrew from the study, died, or turned 15.

Maternal BMI and Measurement

Maternal BMI was assessed at multiple time points:

• At the first antenatal (booking) appointment,
• Again between 26 and 28 weeks’ gestation, and
• During a routine third-trimester appointment.

Approximately 30% of the women were classified as overweight, and 26% were living with obesity—10% of whom had obesity grades 2 or 3 (BMI ≥35) in the first trimester.

Infection Categories and Hospital Admissions

Childhood infections were classified into several categories:

• Upper respiratory tract,
• Lower respiratory tract,
• Skin and soft tissue,
• Genitourinary,
• Gastrointestinal,
• Invasive bacterial, and
• Multisystem viral infections.

Over the follow-up period, 5,009 infection-related hospital admissions were recorded. Around 30% of the children were hospitalised for an infection at least once:

• 19% had one admission,
• 6% had two,
• 4% had three or more.

Admission rates were highest during infancy—134.6 admissions per 1,000 person-years—which declined to 19.9 per 1,000 person-years in children aged 5 to 15.

Maternal BMI and Infection Risk

There was a clear gradient in infection risk according to maternal BMI:

• Children of mothers with a healthy BMI had an admission rate of 39.7 per 1,000 person-years.
• This increased to 60.7 per 1,000 person-years among children whose mothers had obesity grades 2-3.

After adjusting for potential confounders (maternal age, ethnicity, and area deprivation), the risk remained significantly higher in children born to people with obesity grades 2-3:

• These children were 41% more likely to be admitted for an infection under age 1.
• They were 53% more likely to be admitted between ages 5 and 15.

The association appeared stronger in boys than girls and among children of Pakistani mothers compared to those of white British mothers. Respiratory, gastrointestinal, and viral infections accounted for the majority of excess hospital admissions.

Modifiable Risk Factors

The researchers explored whether certain modifiable factors might influence this association:

• Preterm birth accounted for 7% of the link between maternal obesity and infection risk.
• Caesarean section delivery accounted for 21%.
• Child obesity at ages 4–5 contributed to 26%.

Interestingly, breastfeeding for six or more weeks and excessive pregnancy weight gain (both average weekly and total) were not significantly associated with infection risk in this study.

Limitations and Interpretation

As an observational study, the findings cannot establish causality. Several limitations were noted:

• Data came from a single hospital in Bradford, limiting generalisability.
• Missing data for breastfeeding duration and child BMI weakened the completeness of some analyses.
• Environmental and lifestyle factors—such as household crowding or exposure to smoking—were not included.

Despite these limitations, the authors argue that the findings underscore a broader public health concern. They write:

“The findings of our study highlight the need for public health campaigns and additional support for healthcare professionals to help women of reproductive age achieve and maintain a healthy body weight.

“Although the results indicated a modest effect of maternal obesity, and only in those with obesity grades 2–3, the potential effect on a large number of children globally is substantial.”

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Collagen-based protein bars may support weight loss, study suggests

Key Takeaways:

• A 12-week study found that adults with overweight or class 1 obesity who consumed 20g of collagen daily experienced greater weight loss and improved cardiometabolic health compared to a control group.
• The collagen group also reported increased satiety and reduced hunger throughout the study period, without significant loss of fat-free mass.
• While the findings are encouraging, experts caution that collagen is not a substitute for a structured weight management programme and lifestyle change.
  

Background: Obesity Rates and Cost Barriers to Treatment

With over 70% of adults in the United States classified as having overweight or obesity, the demand for effective and affordable weight loss strategies continues to rise. Although medications such as GLP-1 receptor agonists are gaining popularity, their high cost renders them inaccessible for many individuals.

In this context, a recent study published in Nutrients explores whether a more affordable and widely available supplement—collagen—could offer a modest but meaningful aid to weight management.

Study Overview: Collagen Supplementation and Dietary Guidance

Researchers recruited 64 adult participants, all with body mass index (BMI) measurements ranging from overweight to class 1 obesity. All participants were advised to follow a balanced diet modelled on the Mediterranean approach, rich in fruits, vegetables, whole grains, healthy fats, fish, and poultry.

The participants were then randomly assigned to one of two groups:

• Intervention group: 32 individuals consumed two protein bars daily (each containing 10g of bovine-derived collagen and 90 calories).
• Control group: 32 individuals adhered to the dietary recommendations without receiving a protein bar or placebo.

Both groups consumed a similar baseline diet, with the intervention group ingesting slightly more calories due to the added protein bars. Throughout the 12-week period, participants attended regular assessment appointments to collect data on weight, blood pressure, blood biomarkers, urine and faecal samples, and self-reported food intake and appetite levels.

Findings: Greater Weight Loss and Metabolic Improvements in Collagen Group

At the end of the study, the group receiving collagen protein bars demonstrated superior outcomes across several health metrics:

• Average weight loss: 6.6 pounds (≈3kg) in the collagen group compared to 3.3 pounds (≈1.5kg) in the control group.
• Systolic blood pressure: Decreased by an average of 8 mm Hg in the collagen group, while it slightly increased (0.4 mm Hg) in the control group.
• Waist circumference, BMI, and fatty liver index: All improved more significantly in the collagen group.

Importantly, the intervention group retained or improved fat-free mass, indicating preservation of muscle tissue during weight loss—a common concern with calorie reduction strategies.

Participants consuming collagen bars also consistently reported increased satiety and reduced hunger, with these effects sustained across monthly assessments at weeks 4, 8, and 12.

Expert Commentary: Encouraging but Not Conclusive

Despite the promising outcomes, some experts advise caution when interpreting the results.

Dr Mir Ali, a board-certified general and bariatric surgeon and medical director at MemorialCare Surgical Weight Loss Center, told Medical News Today:

“This was a good study that showed the potential benefits of protein bars with collagen. I am not certain that the effects can all be attributed to collagen as protein meal replacements are also beneficial to weight loss.”

Dr Ali emphasised that while collagen appears safe for most people, some may experience minor side effects:

“I am not aware of any major concern with collagen supplements; perhaps a bloating sensation as collagen swells when ingested. Patients with poor gastric motility may feel more bloating, but overall collagen appears safe.”

Strengths and Limitations of the Study

Dr Hector Perez, lead bariatric surgeon at Renew Bariatrics, also commented on the study, calling it:

“A promising and well-structured pilot study.”

He cited the use of validated measures such as DEXA scans, and the focus on both subjective (appetite) and objective (metabolic) outcomes as methodological strengths. However, he also raised a note of caution:

“There’s a theoretical concern about kidney strain in people with impaired renal function if high protein supplements are overused, though this study’s dosage (20g/day) is moderate.”

A key limitation of the study is the potential conflict of interest: some authors are affiliated with the company that manufactures the collagen bars used in the trial.

Conclusion: Collagen as a Complement, Not a Cure

Both Ali and Perez agree that while collagen supplementation may support weight loss, it is not a panacea. Dr Perez summarised:

“I’d recommend collagen as a complement to a structured weight loss programme, not as a stand-alone solution. I always stress that no supplement replaces portion control, physical activity, and sustainable dietary habits.”

For individuals looking for accessible tools to support their weight loss journey, collagen supplements—particularly in protein bar form—may offer an affordable adjunct. However, they should be integrated into a broader, evidence-based approach to long-term weight management.

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Diet-induced obesity linked to anxiety and cognitive impairment in mice

Key Takeaways:

• Obesity in mice was linked to increased anxiety-like behaviours, altered brain signalling, and gut microbiome changes, suggesting a complex interaction between diet, brain function, and gut health.
• Findings reinforce the growing evidence of a gut–brain axis in mental health, highlighting that obesity may contribute directly to cognitive and emotional challenges.
• While conducted in mice, the study supports the value of multi-system approaches to obesity research, prevention, and intervention, particularly during adolescence.

Introduction: Rising Rates, Unanswered Questions

As obesity and anxiety both continue to rise—especially among younger populations—researchers are increasingly investigating whether these conditions are biologically connected. A new preclinical study led by Dr Desiree Wanders, Associate Professor and Chair of Nutrition at Georgia State University, suggests a potential causal link, identifying diet-induced obesity in mice as a driver of anxiety-like behaviours, disrupted brain function, and gut microbiome imbalances.

The findings will be presented at NUTRITION 2025, the annual flagship meeting of the American Society for Nutrition, held from 31 May to 3 June in Orlando, Florida.

Study Design: A Closer Look at the Brain–Gut–Diet Connection

To explore the neurocognitive impact of obesity, researchers developed a mouse model designed to mirror human obesity-related health outcomes. The study involved 32 male mice, observed from six to 21 weeks of age—equivalent to adolescence through early adulthood in humans.

During this time:

• Half of the mice were fed a low-fat diet, while
• The other half received a high-fat diet known to induce obesity.

By the end of the study period, the high-fat group exhibited:

• Significantly greater body weight, and
• Higher levels of body fat than their low-fat-fed counterparts.

Behavioural and Neurological Outcomes

Behavioural tests revealed that mice with obesity displayed more anxiety-like behaviours. Notably, they exhibited increased “freezing” responses—a defensive behaviour in rodents when perceiving threats. This behavioural profile was not seen in the lean control group.

Neurological analysis revealed changes in signalling within the hypothalamus, a brain region that plays a central role in:

• Regulating metabolism,
• Hormonal control, and
• Emotional behaviour.

Such alterations may help explain the cognitive impairments often reported in people living with obesity.

“Several studies have pointed to a link between obesity and anxiety, though it is still unclear whether obesity directly causes anxiety or if the association is influenced by societal pressures. Our findings suggest that obesity can lead to anxiety-like behaviour, possibly due to changes in both brain function and gut health.”
— Desiree Wanders, PhD

Microbiome Findings: Distinct Gut Profiles in Mice with Obesity

Beyond brain signalling, the study also explored the gut microbiota—microorganisms that reside in the gastrointestinal tract and are known to influence both digestion and brain health. In mice with obesity, the researchers observed marked differences in gut microbial composition compared to the lean group.

This supports a growing body of research into the gut–brain axis, suggesting that:

• The microbiome may regulate not only digestion but also emotional and cognitive function.
• Obesity-related changes in gut bacteria may be part of a chain reaction affecting brain health.

Implications for Public and Personal Health

Although animal models cannot replicate the full complexity of human biology and environment, Wanders emphasised the relevance of these results for human health strategies.

“These findings could have important implications for both public health and personal decisions. The study highlights the potential impact of obesity on mental health, particularly in terms of anxiety.”
— Desiree Wanders, PhD

The research adds weight to the argument that obesity’s consequences extend beyond metabolic disease and cardiovascular risk, reinforcing the importance of:

• Preventive strategies, particularly in childhood and adolescence;
• Early interventions, and
• Comprehensive health policies that address mental as well as physical health.

Contextual Considerations and Future Research

Wanders also cautioned against overly simplistic interpretations of the data:

“While our findings suggest that diet plays a significant role in both physical and mental health, it is important to remember that diet is just one piece of the puzzle,” she said. “Environmental factors, genetics, lifestyle choices and socioeconomic status also contribute to the risk of obesity and its associated health outcomes.”

Looking ahead, Wanders and her team plan to:

• Investigate the mechanisms through which diet-induced obesity alters the brain,
• Conduct parallel studies including female mice and different age groups, and
• Explore whether weight loss interventions might reverse or mitigate the observed changes in behaviour, brain function, and gut health.

Presentation Details

Dr Wanders will present the full research findings during the Obesity session at the Orange County Convention Center on Sunday, 1 June, from 11:45 a.m. to 12:45 p.m. EDT.

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Black tea kombucha reduces gut bacteria associated with obesity

Key Takeaways:

• Kombucha altered gut microbial composition, particularly in participants living with obesity, by increasing beneficial bacteria and reducing obesity-linked genera.
• Despite these microbial changes, no significant shifts were observed in short-chain fatty acid levels or markers of intestinal permeability.
• Black tea kombucha is rich in phenolic compounds, notably flavonoids, which may contribute to its potential anti-obesity effects.

Introduction

Obesity remains a mounting global health challenge, currently affecting over one billion people worldwide. This complex condition arises from the interplay of genetic, environmental, physiological, and behavioural factors, though the underlying mechanisms are still incompletely understood. Recent research has increasingly focused on the gut microbiota as a potential contributor to obesity and metabolic dysregulation. Dysbiosis—a disruption in the balance and diversity of gut microbes—has been implicated in the development and progression of obesity.

Diet plays a critical role in shaping the gut microbiome. One food item that has garnered significant attention for its potential microbiota-modulating effects is kombucha—a fermented tea produced using a Symbiotic Culture of Bacteria and Yeast (SCOBY). While numerous animal studies have suggested that kombucha, especially when derived from black tea, can beneficially influence the gut microbiome, evidence from human studies remains scarce.

This study, recently published in The Journal of Nutrition, aimed to address this gap by evaluating the effects of daily black tea kombucha consumption over an eight-week period on gut microbiota composition and intestinal health, in adults with and without obesity.

Study Design and Methods

Participant Selection

Out of 193 online respondents, 62 individuals were screened, and 46 met the eligibility criteria. Participants were divided into two groups based on body mass index (BMI):

• Group with normal-weight: Mean BMI of 21.64 kg/m²
• Group with obesity: Mean BMI of 34.47 kg/m²

Inclusion criteria required participants to be between 18 and 45 years old, have a BMI ≥18.5 kg/m², and be free from chronic diseases aside from obesity. Individuals were excluded for a range of reasons including recent antibiotic use, consumption of kombucha in the past month, vitamin supplementation, chronic medication use affecting lipid or glucose metabolism, unstable body weight, or being pregnant, lactating, or smokers.

Intervention and Data Collection

Participants consumed 200 mL of laboratory-prepared black tea kombucha daily for eight weeks. The kombucha was acidic (low pH) with a mildly sweet taste, achieved by controlled fermentation.

Biological samples (blood, stool, and urine) and lifestyle data were collected at baseline and after eight weeks. Participants were asked to maintain their usual diet and physical activity levels, monitored via the Food Frequency Questionnaire (FFQ) and the International Physical Activity Questionnaire (IPAQ).

Laboratory Analyses

The kombucha’s composition was assessed using:

• High-performance and ultra-performance liquid chromatography (HPLC & UPLC-MS)
• Titration and Folin–Ciocalteu colourimetric assays

Microbial profiling was performed via serial dilution techniques, and intestinal permeability was evaluated using lactulose/mannitol urinary ratios and plasma zonulin concentrations. Stool samples were also analysed for short-chain fatty acid (SCFA) content (acetate, butyrate, and propionate).

Key Findings

Kombucha Composition

The black tea kombucha was found to be rich in 145 phenolic compounds, comprising:

• Flavonoids (81%), notably quercetin 3-O-rutinoside
• Phenolic acids (19%)

These compounds are known for their antioxidant and potential anti-obesity properties.

Microbial Changes

The primary outcomes demonstrated a differential response between the normal-weight group and group with obesity:

• Participants with obesity exhibited:
  • Increased abundance of Subdoligranulum, a beneficial butyrate-producing bacterium
  • Reductions in Ruminococcus and Dorea, both genera associated with obesity and inflammation
• These reductions were particularly noteworthy as both Ruminococcus and Dorea were initially present at significantly higher levels in participants with obesity, but were brought down to baseline levels seen in the normal-weight group by the end of the intervention.
• In both groups, kombucha consumption supported the proliferation of:
  • Bacteroidota
  • Akkermanciaceae, both commensal bacterial families associated with improved metabolic health

Fungal Composition

Although kombucha also altered the gut fungal profile, the effects were less conclusive:

• A modest increase in Saccharomyces was observed
• No significant overall change in fungal alpha-diversity
• Participants with obesity had higher fungal diversity at baseline, which may have declined or shifted over the intervention period

Intestinal Permeability and SCFAs

Despite notable microbial shifts, no statistically significant differences were found in:

• Short-chain fatty acid concentrations in stool samples (acetate, butyrate, propionate)
• Intestinal permeability markers, including:
  • Lactulose-to-mannitol urinary ratio
  • Plasma zonulin levels

This suggests that while the microbiome composition changed, functional and physiological biomarkers remained largely unaltered over the eight-week period.

Physical Activity

IPAQ results confirmed that physical activity levels remained consistent throughout the study. This minimises confounding and supports that observed microbiota changes are likely due to the kombucha intervention rather than lifestyle alterations.

Study Limitations

Several limitations are worth noting:

• Lack of a control group: All participants consumed kombucha, meaning that outcomes cannot be compared to a non-intervention group.
• Short duration: Eight weeks may not be sufficient to observe changes in SCFA production or gut barrier function.
• Sample size: While relatively robust for a pilot nutritional intervention, broader generalisations require larger and more diverse cohorts.
• Self-reported data: Dietary intake and activity levels were self-reported and may be subject to bias or inaccuracies.

Conclusions and Future Directions

This study offers promising early evidence that black tea kombucha consumption can beneficially modulate the gut microbiota, especially in people living with obesity. The findings suggest that kombucha may help rebalance the gut microbial ecosystem by increasing beneficial bacteria and reducing those associated with metabolic dysfunction.

However, the absence of changes in SCFA levels and intestinal permeability markers indicates that microbial compositional changes may not immediately translate into functional physiological benefits within the timeframe observed.

Future research should include:

• A randomised control group for comparison
• A longer intervention duration to detect slower-acting effects
• Clinical endpoints such as weight change, lipid profile, and inflammatory markers to better understand the therapeutic potential of kombucha in obesity management

In summary, daily black tea kombucha consumption over eight weeks resulted in favourable changes to the gut microbial landscape, particularly for individuals with obesity. While more comprehensive studies are needed, these findings contribute to the growing evidence base linking fermented foods to gut and metabolic health.

CCH Insight:

This is a very interesting study, but it raises lots more questions about fermented foods, the gut microbiome and obesity than it answers. The fact that just one drink of kombucha per day can positively influence the balance of the gut microflora in relation to obesity is excellent news, but longer-term studies with more participants are needed to see if kombucha can bring about meaningful metabolic changes. And what about other fermented foods, like kefir, yoghurt, sauerkraut and kimchi? Could they also have positive effects, both individually and synergistically? This is a fascinating area of research, which we follow with great interest at CCH.

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Adolescent obesity linked to structural brain changes affecting memory and emotion

Key Takeaways:

• Adolescents living with abdominal obesity exhibit enlarged brain structures associated with memory, learning, and emotional regulation, particularly the hippocampus and amygdala.
• These neurological changes are compounded by social inequalities, with adolescents in lower-opportunity environments experiencing even more pronounced alterations in brain development.
• The findings underscore the potential long-term cognitive and emotional consequences of adolescent obesity and highlight the importance of early intervention to promote both physical and brain health.

New Research Shows Obesity in Teenagers Alters Brain Development

New findings presented at the European Congress on Obesity (ECO 2025) reveal that adolescents living with obesity—particularly abdominal obesity—exhibit significant alterations in brain structure, with enlarged regions responsible for learning, memory, and emotional regulation.

The research, led by Dr Augusto César F. De Moraes of the UTHealth Houston School of Public Health in Austin, Texas, involved an analysis of thousands of teenagers in the United States. According to Dr De Moraes, “This is particularly alarming, given that the teenage years are such an important time for brain development.” The results raise concerns about the broader neurocognitive implications of adolescent obesity, extending beyond physical health.

A Global Rise in Adolescent Obesity

The prevalence of obesity among children and adolescents has increased dramatically across the globe. Between 1990 and 2022, the proportion of girls living with obesity rose from 1.7% to 6.9%, and among boys, from 2.1% to 9.3%.

In the United States, more than one in three children aged 5 to 14 are now living with overweight or obesity—36.2% of boys and 37.2% of girls—representing over 15 million children. These trends pose an escalating public health challenge, with growing attention now being paid to the cognitive and neurological consequences.

Studying Brain Structure in Adolescents

To explore how obesity and social determinants affect brain development, Dr De Moraes and collaborators from the United States, Brazil, and Spain analysed data from 3,320 children participating in the Adolescent Brain Cognitive Development (ABCD) study. This longitudinal research project investigates how early life experiences influence brain and behavioural development.

Participants, recruited from 21 cities across 17 U.S. states, were followed over four years—initially between 2016 and 2018, and again from 2020 to 2022. At the start of the study, the average age was 9.9 years, with girls comprising 47.4% of the cohort. Obesity status was determined using body mass index and waist circumference, with approximately 34.6% of participants identified as having abdominal obesity at baseline.

Brain Regions Affected by Obesity

Structural MRI scans assessed the volume of key subcortical brain regions, including:

• Hippocampus – involved in memory and learning
• Amygdala – responsible for emotional regulation
• Caudate – plays a role in movement control
• Accumbens, pallidum, putamen, thalamus – other subcortical structures involved in sensory and motor processing

The analysis found that several of these regions were significantly larger in adolescents with abdominal obesity compared to their peers without. The hippocampus was approximately 6.6% larger, and the amygdala 4.3% larger in adolescents with abdominal obesity. Notably, the amygdala was particularly enlarged in those with the highest levels of abdominal fat (waist-to-height ratio > 0.5), prompting concerns about how excess fat might influence emotional processing.

Other brain regions, such as the thalamus and caudate, also exhibited slight increases in size, although these were less pronounced.

The Influence of Social Inequality

To evaluate how environmental factors may further affect brain development, researchers used the Child Opportunity Index, a tool that assesses the quality of a child’s surroundings—including access to education, green space, nutritious food, and neighbourhood safety.

The findings revealed that adolescents from lower-opportunity areas had reduced development in critical brain structures such as the hippocampus, amygdala, and putamen, compared with their peers from higher-opportunity areas. Dr De Moraes stated, “This difference was even more pronounced among adolescents with persistent abdominal obesity.”

These results highlight the compounding impact of both health and social disparities on adolescent neurodevelopment.

Interpreting the Neurological Changes

The researchers caution that both underdevelopment and excessive enlargement of brain structures can be harmful in the context of a developing brain. While reduced brain growth—as seen in adolescents from disadvantaged backgrounds—may reflect stunted neurodevelopment, excessive brain volume—potentially caused by inflammation from obesity—may also interfere with optimal functioning.

Long-Term Implications and the Need for Early Intervention

Dr De Moraes expressed concern about the long-term consequences of these changes, stating:

“Our findings suggest that obesity, particularly abdominal obesity, can impair teenagers’ learning, memory, and emotional control. I worry about how these changes, which are occurring at the age of 13 or 14, might affect them later in life.

There’s even a chance they could be at a higher risk of things like memory problems or dementia as they get older.”

He continued:

“That’s why we believe supporting healthier habits early on is so important, not just for physical health, but for brain health too.

Treating and preventing adolescent obesity won’t only improve health – it may improve brain health, too.”

Conclusion

This large-scale study adds to growing evidence that adolescent obesity, particularly when concentrated in the abdominal region, can have significant effects on brain structure, potentially influencing cognitive and emotional development. These findings emphasise the importance of addressing both obesity and social inequalities early in life to foster not only physical wellbeing but also healthy brain development.

CCH Insight:

The results of this study are concerning. We already know that obesity in childhood can increase the risk of cardiometabolic diseases, but this research suggests the impact could be more wide-ranging and obesity could impair teenagers’ learning, memory, and emotional control. It adds weight to the case for early identification and intervention for children with obesity.

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Adolescent weight-loss surgery on the rise in the U.S. despite availability of new medications

Key Takeaways:

• Weight-loss surgery for adolescents in the United States increased by 15% between 2021 and 2023, even after the approval of new, effective weight-loss medications.
• The study highlights a significant rise in surgery among Hispanic and non-Hispanic Black adolescents, groups disproportionately affected by severe obesity.
• Limited insurance coverage for new weight-loss medications may be influencing the sustained growth in surgery rates despite alternative treatment options.

Significant Rise in Adolescent Weight-Loss Surgery

A recent study led by researchers at UT Southwestern Medical Center has revealed a 15% increase in weight-loss surgeries for adolescents in the United States between 2021 and 2023. The findings, published in The Journal of Pediatrics, provide crucial insights into how severe obesity is being managed among teenagers, a demographic in which this condition is increasing most rapidly.

“The number of U.S. adolescents having access to this treatment that we know is safe and effective is the highest it’s ever been, and hopefully it’s the start of a positive weight loss journey that will get them to better health,” stated Sarah Messiah, Ph.D., M.P.H., Professor of Epidemiology and Associate Dean for Research in the Peter O’Donnell Jr. School of Public Health. Dr. Messiah also serves as Professor of Paediatrics and Director of the Child and Adolescent Population Health Program at UT Southwestern. She co-led the study alongside Sarah Barlow, M.D., M.P.H., Professor of Paediatrics at UT Southwestern.

The Burden of Severe Obesity in Adolescents

In 2018, the combined prevalence of Class II and Class III obesity among U.S. adolescents stood at 9.1%. Severe obesity in young people is linked to numerous health complications, including cardiovascular disease, liver and kidney disorders, obstructive sleep apnoea, and mental health challenges.

Surgery and Medication: Complementary Treatment Options

Metabolic and bariatric surgery (MBS)—which includes procedures such as gastric sleeve, gastric band, and gastric bypass—remains the gold standard for sustained weight reduction and the mitigation of obesity-related health risks in both adolescents and adults. Recently, however, a new class of weight-loss medications known as glucagon-like peptide-1 receptor agonists (GLP-1RAs) has gained substantial popularity. Semaglutide, a notable example, received approval from the U.S. Food and Drug Administration (FDA) for adults in June 2021 and for adolescents in December 2022.

These medications assist individuals in achieving a reduction of 15%–20% of their baseline body weight, offering a non-invasive alternative to surgical interventions. However, Dr. Messiah emphasised that these medications are not yet covered by Medicaid for obesity treatment in the majority of states, including Texas. Coverage by private insurers also remains limited, making these treatments financially inaccessible for many families.

Analysing National Trends in Bariatric Surgery

To better understand trends in MBS amidst the growing availability of weight-loss medications, the research team utilised data from the Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program participant use files. This extensive database contains records from nearly 1,000 accredited medical centres in the United States that perform MBS. The researchers analysed data on adolescents aged 13 to 19, as well as adult patients, who underwent MBS between 2021 and 2023—spanning the period before, during, and after GLP-1RAs were approved for adolescent use. They also examined demographic characteristics of the patients.

Their analysis revealed that adolescent MBS rose from 1,376 procedures in 2021 to 1,581 in 2023. The mean age of adolescent patients undergoing surgery decreased slightly, from 17.91 to 17.79 years. The gastric sleeve was by far the most common procedure, accounting for over 86% of all surgeries.

Among adults, MBS rose from 209,829 procedures in 2021 to 229,159 in 2022 but declined to 216,323 in 2023. The researchers hypothesised that this decline may be attributed to more adults opting for GLP-1RA medications rather than surgery.

Addressing Disparities and Opportunities for Earlier Intervention

This study is the first to demonstrate that a significant portion of the rise in adolescent MBS was driven by increases among Hispanic and non-Hispanic Black young people. These groups are disproportionately affected by severe obesity in comparison to their non-Hispanic white peers. Dr. Messiah noted a concerning finding that approximately one-third of adolescents undergoing MBS had a body mass index (BMI) exceeding 50. She highlighted that earlier intervention with MBS could have supported these individuals in reducing their BMI at younger ages, thereby lessening their long-term health risks.

“Severe obesity is very common, much more common than it should be, and it is unlikely to respond to lifestyle interventions alone. I think the relative number of bariatric surgeries is still pretty low, given the potential benefit and need among kids,” said Dr. Barlow.

A Combined Approach for the Future

Looking ahead, the researchers anticipate that effective treatment for severe obesity will increasingly involve a combination of MBS, weight-loss medications, and lifestyle interventions to support sustained improvements in health.

Acknowledgements and Funding

The study’s co-authors included Faisal Qureshi, M.D., M.B.A., Professor of Paediatrics and Surgery; Alicia Wheelington, Ph.D., Assistant Professor of Psychiatry; Bethany Cartwright, M.D., Ph.D., Assistant Professor of Paediatrics; Benjamin Schneider, M.D., Professor of Surgery and Chief of the Division of Bariatric and Foregut Surgery; Ildiko Lingvay, M.D., M.P.H., M.S.C.S., Professor of Internal Medicine and in the O’Donnell School of Public Health; Jaime Almandoz, M.D., M.B.A., Associate Professor of Internal Medicine; M. Sunil Mathew, M.S., Senior Population Science Data Manager; and Jackson M. Francis, M.P.H., Population Science Project Coordinator.

This research was funded by a grant from the National Institute of Child Health and Human Development (R21HD105129).

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Popular sweetener sucralose may intensify hunger signals and contribute to weight gain, new study suggests

With over 20% of adults in the United States living with obesity, there is significant interest in foods and beverages that can help manage weight. Among the most commonly used tools in calorie reduction are non-caloric sweeteners, which are often marketed as effective aids in weight control. However, a new study raises concerns that one such sweetener—sucralose—may, in fact, increase hunger and contribute to overeating.

The research, conducted by scientists at the Diabetes and Obesity Research Institute at the University of Southern California, examined how sucralose influences brain activity related to hunger. Using functional magnetic resonance imaging (fMRI), the researchers observed how the brain’s hypothalamus—a key region involved in appetite regulation—responded after consumption of drinks sweetened with sucralose, sucrose (table sugar), or plain water.

The study’s findings, published in Nature Metabolism, suggest that sucralose may significantly increase hunger-related brain signals compared to both sugar and water, a response that could lead to heightened appetite and greater food consumption.

Understanding Sucralose and Its Impact on the Brain

Sucralose is an artificial sweetener known for its high sweetness potency—estimated to be between 385 and 650 times sweeter than sucrose by weight. Despite its popularity as a sugar substitute, the long-term effects of sucralose on appetite and metabolism are still being explored.

To investigate further, researchers recruited 75 adults aged 18 to 35, representing three different weight categories: healthy weight, overweight, and obesity. Each participant took part in three separate experimental sessions, during which they consumed either a sucralose-sweetened drink, a sucrose-sweetened drink, or water. Brain scans were taken before the drink and at intervals of 10, 35, and 120 minutes afterward. Participants also provided self-reported hunger ratings during each session.

The hypothalamus, the brain region of focus in this study, plays a critical role in maintaining various physiological functions, including temperature regulation, hormone production, and hunger signalling. Increased blood flow in the hypothalamus is associated with stronger hunger signals.

Sucralose Heightens Hunger Signals, Especially in Some Groups

The analysis revealed that sucralose increased hypothalamic blood flow more than both water and sucrose, indicating a heightened hunger-related brain response. This finding was consistent across the overall participant group but varied when broken down by weight category and sex.

• People at healthy weights showed a greater increase in hypothalamic activity after consuming sucralose compared to sucrose.
• People with overweight did not exhibit significant differences in hypothalamic blood flow across the three beverages.
• People living with obesity experienced increased hunger-related brain activity after consuming sucralose compared to water—but not when compared to sucrose.

These results suggest that while sucralose may not affect everyone equally, it can still trigger hunger signals in a substantial portion of the population.

Further differences emerged when sex was considered:

• Female participants displayed a more pronounced brain response to sucralose in comparison to both sugar and water. The researchers suggest this supports previous findings that women may have a stronger neurological reaction to food-related cues.

Additionally, the researchers found that sucralose significantly increased functional connectivity between the hypothalamus and the anterior cingulate cortex, a brain region involved in reward processing. This enhanced coupling may further intensify food cravings and undermine weight control efforts.

Hunger Ratings Support Brain Imaging Findings

Self-reported hunger levels added further support to the brain imaging data. Participants began each session with similar hunger levels regardless of the drink they were about to consume. However, following drink consumption, those who had consumed the sucralose-sweetened beverage reported higher hunger compared to when they had consumed the sucrose-sweetened drink. Interestingly, sucralose did not produce a greater hunger response than water in these subjective ratings.

The researchers hypothesise that this might be due to the body’s hormonal response. Sucralose may fail to activate the same satiety-related hormones that are typically released in response to calorie-containing foods or beverages, potentially leading to a mismatch between perceived sweetness and physiological satiation.

While more studies are needed to confirm the hormonal mechanisms, these results suggest that sucralose could inadvertently stimulate appetite, counteracting its intended use as a calorie-free sugar alternative for weight loss.

Clinical Perspectives on the Findings

The potential implications of this study extend into clinical practice. Dr Mir Ali, a board-certified general surgeon and bariatric specialist, as well as the medical director of MemorialCare Surgical Weight Loss Center, discussed the findings with Medical News Today.

“Based on this study, it seems that the brain processes non-caloric sweeteners to the same or greater extent than actual sugar,” said Dr Ali.

He suggested that this might influence how clinicians advise their patients:

“We already recommend that our patients emphasise protein and non-starchy vegetables in the diet and minimise carbohydrates and sugars,” Dr Ali noted. “After this study, I’m also inclined to recommend my patients minimise non-caloric sweeteners as well.”

Registered dietitian Eliza Whitaker, MS, RDN, founder of Nourished Nutrition and Fitness, also shared her insights with Medical News Today:

“This could suggest that the brain expects energy from calories when eating something sweet. However, this expectation is not met when consuming non-caloric sweeteners, like sucralose, which may prevent the processes within the hypothalamus that reduce appetite after eating something sweet from occurring the way they do when consuming calorie-containing sweeteners.”

Whitaker noted that the current evidence would not prompt a change in her clinical recommendations yet, but acknowledged the need for individualised consideration:

“It may be beneficial to assess sucralose intake for someone who has made other dietary adjustments and feels they are still unable to reach their health goals,” she commented.

Final Thoughts

This study provides compelling evidence that sucralose, a widely used non-caloric sweetener, may not function as neutrally in the body as once assumed. Instead of helping people feel satisfied while avoiding calories, it may actually intensify hunger signals and lead to greater food intake—especially among people with healthy weights and women.

While further research is necessary to clarify the long-term effects and hormonal mechanisms involved, the findings offer a cautionary note for individuals and clinicians who rely on non-caloric sweeteners as part of a weight management strategy. As the scientific community continues to investigate how artificial sweeteners interact with human metabolism and brain function, personalised and evidence-informed dietary guidance remains essential.

CCH Insight:

The instinctive reaction to this might be “there’s no point in consuming sucralose because it stimulates appetite”. However, if consuming sucralose means you avoid eating/drinking refined sucrose, and then you eat something healthy and nutritious when the sucralose stimulates your appetite, this is undoubtedly a benefit, even if calorie intake is not reduced. Further research is needed to determine how people respond in real life to the increased appetite stimulated by sucralose. 

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High sodium intake strongly linked to increased risk of both general and abdominal obesity, Finnish study finds

A new Finnish study, to be presented at the upcoming European Congress on Obesity (ECO 2025) in Malaga, Spain (11–14 May), has found a significant association between dietary sodium intake and the likelihood of both general and abdominal obesity. The research, led by Annika Santalahti from the Finnish Institute for Health and Welfare in Helsinki, offers further evidence of the potential health risks posed by excessive sodium consumption.

General obesity is defined by a person’s body mass index (BMI), with the World Health Organization (WHO) stating that a BMI of 30 kg/m² or more constitutes obesity. Abdominal obesity, on the other hand, refers to the accumulation of fat around the abdomen and internal organs, leading to an enlarged waist circumference. This central distribution of fat is known to increase the risk of cardiovascular diseases.

Background: A Growing Body of Evidence

The study builds on a growing body of evidence suggesting a positive relationship between high sodium intake and increased risk of obesity. Historically, sodium consumption in Finland had declined from the 1970s—when the country faced some of the world’s highest rates of heart disease—but has largely plateaued since 2007.

The researchers explain:

“Contrary to popular belief, high sodium intake is not mainly caused by unhealthy foods, but by ordinary everyday food. In Finland, most sodium is obtained from processed meat products, bread and dairy products, especially cheese. High sodium intake cannot only be addressed at an individual level—changes at the population level are also needed and can only be achieved through cooperation with the food industry.”

Study Design and Methods

This new study examined data from the National FinHealth 2017 Study, a population-based study of Finnish adults aged 18 and over. It included 2,222 men and 2,792 women. Sodium intake was estimated using a validated food frequency questionnaire, and spot urine samples were collected from a subsample of participants (558 men and 702 women). General obesity was assessed using BMI, while waist circumference measurements were used to determine abdominal obesity.

Sodium intake and urine sodium concentrations were divided into sex-specific quartiles (four equally sized groups based on intake levels). Statistical modelling was conducted to examine associations, adjusting for sociodemographic and lifestyle-related confounders. Spot urine samples were validated by comparison with 24-hour urine collection data.

Key Findings: Sodium Intake Exceeds Recommendations

Across all but the lowest quartile of women, sodium intake exceeded WHO recommendations of 5 grams of salt (sodium chloride) per day. In the highest quartile, sodium intake was 2.3 times higher than in the lowest quartile for both men and women combined. Men consistently reported higher sodium intake than women across all quartiles.

Self-reported estimates from food questionnaires suggested that men in the highest quartile consumed approximately 4,900 mg of sodium per day, equivalent to over 12 grams of salt. Women in the same quartile consumed around 3,750 mg of sodium daily—translating to roughly 9 grams of salt. These levels significantly exceed WHO recommendations and suggest a worrying trend.

Obesity Risk Increases with Sodium Intake

The researchers found that participants with higher dietary sodium intake or higher urine sodium concentrations were more likely to be living with either general or abdominal obesity. Among women, those in the highest quartile for sodium intake were:

• 4.3 times more likely to be living with general obesity, and
• 3.4 times more likely to be living with abdominal obesity compared to those in the lowest quartile.
  

Women in the second highest quartile also had significantly increased risk, being 2.4 times more likely to have general obesity than those in the lowest quartile.

Comparable findings emerged when using urine sodium concentrations. For instance, women in the highest urine sodium quartile were 4.8 times more likely to be living with obesity than those in the lowest quartile—almost identical to the 4.3-fold increase observed through dietary data.

Stronger Associations Observed in Men (Urine Data)

While men showed a similar pattern in obesity risk when sodium intake was assessed through dietary questionnaires, the results were not statistically significant across all quartiles. However, when analysing urine sodium concentrations, statistically significant associations emerged. Men in the highest urine sodium quartile were:

• 6 times more likely to be living with general obesity, and
• 4.7 times more likely to be living with abdominal obesity compared to those in the lowest quartile.
  

The authors note that the spot urine measurements corresponded moderately well with 24-hour collections, suggesting a reasonably accurate categorisation of participants into high and low sodium intake groups.

Possible Explanations and Biological Mechanisms

On the stronger associations observed in men, the authors explain:

“In general, men consume more food, and also more of foods that are the main food sources of sodium in the diet, such as meat products, bread and bakery products, and cheese. Our analyses were adjusted for total energy intake and therefore the stronger associations in men might be due to the higher salt intake relative to total energy intake. However, regardless of the magnitude of the relationship, the associations were in similar direction in both men and women.”

The underlying biological mechanisms for this link remain uncertain. The authors state:

“The association between salt intake and obesity is still very unclear, and there are no waterproof explanations for the differences between sexes nor for the phenomenon in general. Research data is still very limited, but possible biological explanations have included changes in the secretion of satiety hormones as a result of long-term exposure to high salt intake. High salt intake may also act as a proxy for nutrition quality as a whole—overconsumption of food giving high levels of sodium and increasing the risk of obesity, possibly reflecting overconsumption of ultra-processed, high-sodium foods.”

Further investigation is required to better understand the relationship between sodium intake and obesity, including studies examining satiety signalling, the gut microbiome, and body composition.

Public Health Implications and the Role of the Food Industry

The researchers emphasise that reducing sodium intake should not rest solely on individuals. They argue for a systemic approach involving the food industry:

“In our view, the food industry plays a significant role in reducing the population’s sodium intake, as the majority of food consumption comes from sources other than unprocessed primary production. It is important to pay attention to how salty commonly consumed daily foods are, as these account for a large proportion of the daily sodium intake. Of course, general changes in the food environment also play a role, such as whether food is prepared at home or consumed in restaurants or as takeaway food.”

Conclusion

The study provides compelling evidence linking high sodium consumption—measured through both diet and urine samples—with an increased likelihood of general and abdominal obesity. These findings highlight the urgent need for further research and broader societal changes, particularly in food production and labelling, to help reduce sodium intake across populations. As the authors conclude:

“These results strengthen the evidence of an association between sodium intake and obesity, with similar findings observed for both dietary sodium and urine sodium concentration. It is important to gain more understanding about the biological mechanism of the relationship.”

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