Obesity Care

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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Artificially sweetened drinks in pregnancy linked to higher risk of overweight in offspring, Danish study finds

A large Danish cohort study published in the British Journal of Nutrition has found a significant association between maternal consumption of artificially sweetened beverages (ASBs) during pregnancy and an increased risk of overweight in their children from mid-childhood through to adolescence. The findings raise new questions about the long-term effects of artificial sweeteners during pregnancy, especially among women seeking alternatives to sugar to manage gestational weight.

Background

Childhood obesity has more than doubled over the past three decades, with excess weight in early life known to heighten the risk of type 2 diabetes, cardiovascular disease, and other long-term health conditions. Many pregnant individuals opt for diet drinks containing artificial sweeteners to avoid excess calorie intake and potential weight gain. These beverages are commonly perceived as a healthier substitute for sugar-sweetened alternatives.

However, emerging evidence suggests that artificial sweeteners may have unintended metabolic consequences, including disruption of gut microbiota, altered insulin responses, and increased cravings for sweet foods—even before birth. Although previous studies have reported conflicting results, some have linked prenatal exposure to ASBs with a higher likelihood of obesity in offspring. Given the widespread consumption of artificially sweetened products during pregnancy, further research into their long-term health implications is essential.

Study Design and Methodology

The present study is based on data from the Danish National Birth Cohort (DNBC), a nationwide longitudinal study that enrolled 101,042 pregnant women between 1996 and 2002. Participants were followed throughout pregnancy and their children tracked up to the age of 18.

Researchers collected detailed dietary and lifestyle information through telephone interviews at gestational weeks 12 and 30, and again at 6 and 18 months postpartum. A comprehensive food frequency questionnaire was administered at week 25 of pregnancy, capturing the frequency of ASB and sugar-sweetened beverage (SSB) intake. Consumption was categorised into four levels: none, less than one 250ml serving per week, 1–6 servings per week, and one or more servings per day.

The primary outcomes of interest were large-for-gestational-age (LGA) birth weight and overweight status of offspring at multiple time points: 5 and 12 months, and ages 7, 11, 14, and 18 years. Height and weight data were obtained from a combination of healthcare providers, parental reports, and self-reports by adolescents. Overweight status was defined using sex- and age-specific body mass index (BMI) cut-offs derived from standard deviation scores.

Women with pre-existing diabetes or incomplete data were excluded. Researchers adjusted for a wide range of confounding variables, including maternal age, pre-pregnancy BMI, smoking, physical activity, socioeconomic status, dietary quality (including SSB intake via the Healthy Eating Index), paternal BMI, and breastfeeding duration. Analyses were conducted using multiple logistic and linear regression models in R software.

Key Findings

Of the full cohort, 66,668 individuals provided valid data on ASB consumption, and 66,568 on SSB intake. Researchers found that women who consumed one or more servings of ASB per day were generally younger, had a higher pre-pregnancy BMI, were more likely to smoke, and had lower socioeconomic status. In contrast, those consuming fewer than one ASB per week tended to be more physically active and breastfed their infants for longer durations.

Early Life Outcomes
In infancy (at birth, 5 months, and 12 months), no association was found between maternal ASB consumption and increased risk of LGA or overweight in children.

Later Childhood and Adolescence
However, a consistent association emerged from age 7 onwards. Children whose mothers consumed either 1–6 ASBs per week or one or more per day during pregnancy had significantly higher odds of being overweight at ages 7, 11, 14, and 18 years, compared with children of mothers who reported no ASB consumption.

After adjusting for relevant confounding factors, daily ASB consumption remained significantly associated with higher overweight risk in offspring. At 18 years of age, the adjusted odds ratio (OR) for being overweight in the group exposed to ≥1 ASB per day was 1.26 (95% confidence interval [CI]: 1.12–1.42) compared to the non-exposed group. This pattern supports a potential dose-response relationship, where higher ASB intake correlates with greater risk.

SSBs and Unexpected Findings
Surprisingly, maternal consumption of SSBs was linked to a lower risk of overweight in offspring at ages 11 and 18. For example, children of mothers who consumed one or more SSBs daily had an adjusted OR of 0.72 (95% CI: 0.60–0.86) for overweight at 18 years, compared to those whose mothers did not consume SSBs. These findings were echoed in BMI z-scores: offspring exposed to ≥1 ASB per day had higher scores, while those exposed to ≥1 SSB per day had lower scores.

Researchers cautioned, however, that these inverse associations with SSBs could be influenced by unmeasured differences in socioeconomic or lifestyle factors. Mothers consuming SSBs tended to have lower pre-pregnancy BMIs and higher socioeconomic status, which may have contributed to the unexpected results, although adjustments were made for these variables.

Additional Analyses

Subgroup analyses, which used total energy intake as an adjustment factor rather than the Healthy Eating Index, yielded only minor differences in ASB-related outcomes, suggesting that the observed associations were not solely attributable to higher overall calorie intake.

Further modelling, in which ASBs were theoretically substituted with SSBs, indicated a reduced risk of overweight, reinforcing the hypothesis that artificial sweeteners themselves may play a role in long-term weight outcomes for children.

Of particular note is the timing of the observed effects: associations with overweight status only emerged from age 7 onwards. There was no elevated risk detected in infancy, which the authors suggest may reflect the onset of independent eating behaviours and the influence of early taste preferences shaped in utero. “These findings support the hypothesis that prenatal exposure to artificial sweeteners may alter long-term metabolic or taste-related pathways,” the authors noted.

Nevertheless, the study was unable to fully exclude the possibility of residual confounding by factors not captured in the dataset, such as the child’s postnatal diet or physical activity levels. Moreover, a significant data gap between 12 months and 7 years limits understanding of when weight differences may first begin to emerge.

The researchers also raised the possibility that individuals consuming ASBs during pregnancy might continue their use postpartum, potentially passing on artificial sweeteners through breastmilk. However, this remains speculative and was not directly examined in the study.

Implications and Conclusions

This large-scale cohort study adds to a growing body of evidence suggesting that consumption of artificially sweetened drinks during pregnancy may have unintended long-term consequences for the offspring. While the absolute increase in overweight risk is modest, the association persisted consistently across multiple age points and appeared to follow a dose-dependent pattern.

In contrast, the observed lower risk of overweight associated with SSB consumption should be interpreted cautiously. The authors emphasised that this may not reflect a protective effect of sugary drinks, but rather underlying lifestyle or demographic differences.

“These results challenge the current dietary recommendations for pregnant individuals—particularly those with overweight or diabetes—who are often encouraged to substitute sugar with artificial sweeteners,” the authors wrote.

Although more research is needed to clarify mechanisms and account for limitations such as the postnatal diet and the mid-childhood data gap, the study calls for a re-examination of nutritional advice during pregnancy. It also highlights the need for further investigation into safer and more effective alternatives for managing gestational weight.

Given the rising prevalence of childhood obesity, even small shifts in population-level risk carry important public health implications.

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High-fat diet and obesity impair key immune functions, new study finds

A recent study published in The Journal of Immunology has shed new light on how a high-fat diet (HFD) and obesity can compromise the immune system’s ability to fight infection. The research focuses on neutrophils—white blood cells that serve as one of the body’s first lines of defence against invading bacteria and viruses—and reveals that exposure to a high-fat diet alters their number, maturity, and function.

The study was led by Dr Kanakadurga Singer, Associate Professor in the Departments of Paediatrics and Molecular & Integrative Physiology at the University of Michigan Medical School. Her team used a widely accepted mouse model to examine the effects of a high-fat diet on immune response. Male mice were fed either a standard diet or a high-fat diet known to induce obesity. The researchers then isolated neutrophils from the animals’ blood and bone marrow to assess their function.

Mice fed the high-fat diet not only had an increased number of neutrophils but also displayed significant changes in the characteristics of these cells. Many of the neutrophils were either immature or aged, and crucially, they showed a diminished ability to kill bacteria.

“When neutrophils were exposed to Pseudomonas aeruginosa, a bacterium known to cause pneumonia, the neutrophils from high-fat diet-fed mice exhibited a significantly reduced capacity to ingest and eliminate the bacteria,” the study reported. This impaired response suggests that individuals with obesity may have weakened early immune defences, increasing their susceptibility to infection.

In addition to compromised bacterial killing, neutrophils from the high-fat diet group demonstrated alterations in gene expression related to fat storage and metabolism. They also showed a reduced ability to store and release tumour necrosis factor-alpha (TNF-α), an important signalling molecule that regulates inflammation and immune responses.

The findings are particularly relevant given the high prevalence of obesity. In the United States, 40.3% of adults are currently living with obesity—a condition that often develops when energy intake consistently exceeds energy expenditure, especially through diets rich in fat and/or sugar. Obesity is increasingly recognised as a state of chronic, low-grade inflammation, which is believed to contribute to the development of various obesity-related conditions, including impaired immunity.

“The link between chronic inflammation and increased infections highlights the importance of understanding how immune cells like neutrophils are affected by obesity,” explained Dr Singer. “We hope that by understanding how neutrophil function is altered with exposure to high-fat diet, we can take future steps to restore function and improve patient health outcomes.”

She added:

“We hope this study lets investigators and clinicians know that although neutrophils may be increased in number in individuals with elevated BMI or diet-induced obesity, these neutrophils may not be functional.”

The study offers important insights into how dietary patterns and weight status can influence immune health. The next step, according to Dr Singer, is to explore the underlying mechanisms driving neutrophil dysfunction in the context of a high-fat diet.

“We hope to build on these findings by uncovering what is causing the impairment of neutrophils exposed to HFD,” she said. “My team plans to conduct further studies on why these neutrophils are defective, especially in their bacterial killing function, and if these neutrophils are impaired in killing specific types of bacteria or a wide range. Hopefully, we can identify other implications of neutrophil dysfunction due to HFD and if there are ways to improve this impaired function.”

This research underscores the complex interplay between nutrition, body weight, and immune function, reinforcing the need for a deeper understanding of how diet-induced obesity affects health at the cellular level.

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Waist-to-height ratio identified as a more precise indicator of childhood obesity than BMI, study finds

A recent study has highlighted the limitations of body mass index (BMI) in accurately identifying overweight and obesity in children and adolescents. Researchers found that BMI was nearly three times more likely to classify children as overweight when compared to waist-to-height ratio, a measurement that better reflects body fat distribution. The study, a collaborative effort between the University of Eastern Finland and the Universities of Bristol and Exeter in the United Kingdom, was published in Obesity and Endocrinology. 

BMI is widely used as a screening tool for childhood obesity, as it is a simple calculation based on weight and height. However, one of its key limitations is that it does not differentiate between fat mass and lean muscle mass. This means that children with a higher proportion of muscle could be mistakenly classified as overweight or obese.

In contrast, waist-to-height ratio takes into account central adiposity—the accumulation of fat around the abdomen—which is a more reliable predictor of obesity-related health risks. Recognising this, leading health organisations have begun to shift their recommendations regarding obesity assessment. The Lancet Commission on Obesity and the European Association for the Study of Obesity (EASO) have both advised that BMI alone should not be used as the sole diagnostic measure for obesity in adults. Instead, they recommend confirming obesity using waist-to-height ratio or other indicators. Similarly, the UK’s National Institute for Health and Care Excellence (NICE) has endorsed waist-to-height ratio as a useful tool for predicting obesity-related health risks in children, particularly those linked to central fat accumulation.

Largest Longitudinal Study Comparing BMI and Waist-to-Height Ratio in Children

This latest study represents the most extensive follow-up research globally to compare BMI and waist-to-height ratio in paediatric populations. The study followed 7,600 children from the University of Bristol’s Children of the 90s cohort, tracking their growth and body composition changes from the age of 9 years through to 24 years.

At the age of 9, researchers identified 1,431 children as overweight based on BMI. However, when these same children were assessed using waist-to-height ratio, the findings were markedly different:

• 25% were classified as having high fat
• 11% had excess fat
• 64% had normal fat levels, according to the study’s waist-to-height ratio cutpoints

Conversely, among the 517 children classified as having high fat based on waist-to-height ratio:

• 70% were classified as overweight by BMI
• 24% were classified as having obesity by BMI
• Only 6% were within the normal BMI range

These findings underscore the risk of BMI misclassifying children’s weight status, either overestimating or underestimating body fat levels.

Waist-to-Height Ratio as a More Accessible Alternative to DEXA Scanning

For precise measurement of body fat, dual-energy X-ray absorptiometry (DEXA) is considered the gold standard. However, this technology is expensive and not widely available in primary care settings. Previous research using the same dataset demonstrated that waist-to-height ratio can predict body fat with up to 85% accuracy when compared to DEXA results. The cutpoints for high, excess, and normal body fat used in this study were derived from earlier findings in the same cohort of children and adolescents.

Furthermore, the validity of these cutpoints was externally tested in a separate population of 3,329 adults in the United States to assess their predictive value for metabolic health outcomes. Researchers found that:

• High waist-to-height ratio fat levels were associated with increased odds of prediabetes
• Excess waist-to-height ratio fat levels correlated with a higher risk of developing type 2 diabetes

These results highlight the potential for waist-to-height ratio to serve as a universal and cost-effective screening tool for obesity-related health risks across different age groups and populations.

Expert Perspective: Waist-to-Height Ratio as a More Reliable Metric for Childhood Obesity

Dr Andrew Agbaje, a physician and associate professor (docent) of Clinical Epidemiology and Child Health at the University of Eastern Finland, emphasised the advantages of waist-to-height ratio as a more precise measure of adiposity in young people.

“Waist-to-height ratio is an affordable and universally accessible, accurate, and precise tool for detecting high and excess fat in children and adolescents,” he stated.

His previous research has demonstrated that waist-to-height ratio is a strong predictor of both total body fat and central fat distribution, reinforcing its value in obesity assessment.

“Overweight and obesity in children and adolescents should not be diagnosed with BMI alone but could be confirmed with waist-to-height ratio where a DEXA scan is lacking,” Agbaje concluded.

Research Funding and Support

Agbaje’s research has been made possible through financial support from multiple organisations, including:

• Jenny and Antti Wihuri Foundation
• Finnish Cultural Foundation (Central Fund and North Savo Regional Fund)
• Orion Research Foundation
• Aarne Koskelo Foundation
• Antti and Tyyne Soininen Foundation
• Paulo Foundation
• Yrjö Jahnsson Foundation
• Paavo Nurmi Foundation
• Finnish Foundation for Cardiovascular Research
• Ida Montin Foundation
• Eino Räsänen Fund
• Matti and Vappu Maukonen Fund
• Foundation for Paediatric Research
• Alfred Kordelin Foundation
• Novo Nordisk Foundation

Implications for Future Obesity Screening and Management

The findings of this study contribute to the growing body of evidence suggesting that waist-to-height ratio should be incorporated into routine obesity screening in children and adolescents. Given its affordability, accessibility, and stronger correlation with body fat distribution, it presents a valuable alternative to BMI in both clinical and public health settings.

As global obesity rates continue to rise, ensuring the accuracy of diagnostic tools is essential for early intervention and effective management. This research reinforces the need for a shift in obesity screening practices, with waist-to-height ratio emerging as a more reliable and equitable measure of adiposity in young people.

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Chronic stress and obesity identified as accelerators of early pancreatic cancer development

A groundbreaking study led by researchers at the University of California, Los Angeles (UCLA) has uncovered a significant link between chronic stress, obesity, and the early progression of pancreatic cancer. The findings provide new insights into how lifestyle factors can influence the onset and severity of one of the most aggressive and deadly forms of cancer.

Understanding the Biological Link Between Stress, Obesity, and Pancreatic Cancer

Through preclinical models, scientists identified a key molecular mechanism that explains how both stress and obesity can trigger changes in pancreatic cells, potentially leading to cancerous growth. The study revealed that stress-related neurotransmitters and obesity-associated hormones activate a protein called CREB, which is closely linked to cancer cell proliferation. Interestingly, these two factors stimulate CREB via distinct biological pathways:

• Stress hormones engage the β-adrenergic receptor/PKA pathway
• Obesity-related hormones predominantly activate the PKD pathway

Despite originating from separate physiological processes, both pathways ultimately contribute to the same oncogenic effect, suggesting that chronic stress and obesity work in tandem to promote pancreatic cancer progression.

Preclinical Findings: Diet, Social Stress, and Cancer Risk

In a series of mouse experiments, researchers found that a high-fat diet alone was sufficient to induce the growth of precancerous pancreatic lesions. However, when combined with social isolation stress, the mice developed significantly more advanced lesions, indicating that stress can compound the harmful effects of an unhealthy diet.

Notably, the study also observed sex-specific differences in how stress influenced cancer progression. Female mice subjected to social isolation exhibited a more pronounced acceleration in cancerous changes compared to their male counterparts. The researchers hypothesise that this disparity could be linked to differences in biological stress responses, particularly the influence of oestrogen and heightened β-adrenergic receptor activity, which may increase susceptibility to stress-induced cancer development.

Potential Clinical Implications and Treatment Strategies

The findings suggest that stress and obesity-driven molecular pathways play a crucial role in accelerating pancreatic cancer onset. This raises the possibility of leveraging existing medications to mitigate these risks. As β-adrenergic receptors appear to be central to stress-induced cancer growth, commonly prescribed beta-blockers—widely used for managing high blood pressure—could be repurposed as a preventive strategy to slow down cancer progression in at-risk individuals.

While further clinical research is needed to confirm these findings in human populations, the study provides compelling evidence that lifestyle factors can significantly influence cancer risk. Interventions targeting stress management, diet modification, and pharmacological prevention may collectively contribute to reducing the incidence of pancreatic cancer.

Publication Details

The study was published in Molecular Cancer Research, offering critical insights into the interplay between stress, obesity, and cancer biology.

Research Team

The study’s first authors are Xiaoying Sun, a postdoctoral researcher in the departments of medicine and surgery at UCLA, and Yaroslav Teper, a project scientist at the David Geffen School of Medicine at UCLA. The senior authors include Dr. Guido Eibl, professor in residence in the department of surgery at UCLA Health, and Dr. Enrique Rozengurt, distinguished professor of medicine and chief of research in the division of digestive diseases at UCLA.

Other contributing authors, all affiliated with UCLA, include James Sinnett-Smith, Mineh Markarian, Dr. Joe Hines, and Dr. Gang Li. Additionally, Eibl, Rozengurt, Hines, and Li are members of the UCLA Health Jonsson Comprehensive Cancer Center.

Funding and Support

The research received funding from several prestigious institutions, including:

• National Cancer Institute
• National Institute of Allergy and Infectious Diseases
• Ronald S. Hirshberg Endowed Chair of Pancreatic Cancer Research
• Ronald S. Hirshberg Foundation

These findings highlight the critical need for public awareness and proactive health measures to reduce stress and maintain a healthy lifestyle as potential strategies for cancer prevention.

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Smoking and obesity combined may greatly accelerate multiple sclerosis progression, study finds

New Research Highlights the Amplified Risk of Disease Progression and Cognitive Decline

A recent study has found that smoking and obesity, two well-known risk factors for multiple sclerosis (MS) progression, may have a compounding effect when present together. Among 3,336 individuals with MS, researchers observed that those who both smoked and were living with obesity faced a significantly increased risk of disease progression and cognitive decline compared to those who had neither risk factor. These findings highlight the importance of lifestyle interventions in managing MS and potentially slowing its progression.

Background: The Known Risks of Smoking and Obesity in MS

Previous studies have established that both smoking and obesity independently contribute to the progression of MS. Individuals with MS who smoke have been found to experience faster deterioration in physical and cognitive functions, while obesity has been linked to increased inflammation and greater disability over time.

Outside of MS, research in conditions such as heart disease and diabetes has shown that smoking and obesity do not merely add to the risk of poor health outcomes—they interact in ways that amplify those risks beyond what would be expected from either factor alone. However, until now, limited research has explored whether this type of interaction also occurs in MS. Understanding whether these risk factors reinforce each other in MS progression could be critical in developing more effective prevention and management strategies.

Study Overview: Investigating the Combined Effects of Smoking and Obesity

A team of researchers from the Karolinska Institute in Sweden conducted an extensive review of medical records from 3,336 individuals with MS. Their aim was to determine whether smoking and obesity interact to worsen disease progression and cognitive decline.

To measure disease progression, the researchers used the Expanded Disability Status Scale (EDSS), a standardised system that evaluates disability levels in people with MS. The EDSS assesses a range of neurological functions, including walking ability, muscle strength, vision, and cognitive performance.

Key Findings: A Significant Interaction Between Smoking and Obesity

Consistent with previous research, the study confirmed that both smoking and obesity independently increased the risk of faster disease progression. Smoking was also linked to a greater likelihood of cognitive impairment. However, the most striking finding was that the combination of these two risk factors led to an even greater acceleration of MS progression and cognitive decline.

When comparing different groups of people with MS:

• Non-obese smokers had a 21% higher risk of reaching EDSS level 4 (which signifies significant disability but preserved walking ability) compared to non-smokers who were not obese.
• Individuals who were obese but did not smoke had a 33% higher risk of reaching EDSS 4.
• However, individuals who both smoked and were living with obesity had an 86% higher risk of reaching EDSS 4, demonstrating that these two factors together substantially increase the likelihood of disability progression.

In addition to physical disability, the study found that smoking and obesity also interacted to exacerbate cognitive decline, further impairing memory, concentration, and problem-solving abilities in individuals with MS.

Implications: The Importance of Modifiable Risk Factors

The findings of this study are particularly significant because both smoking and obesity are modifiable risk factors. Unlike genetic predisposition or other non-preventable aspects of MS, these behaviours can be changed, offering individuals the opportunity to potentially slow their disease progression.

“This study suggests that dropping even one unhealthy habit could potentially lead to a substantially reduced risk of unfavourable disease outcomes,” the researchers noted.

For individuals with MS, quitting smoking and achieving a healthy weight could have far-reaching benefits, not only in terms of reducing the risk of disability but also improving overall well-being. There are numerous resources available to support these lifestyle changes, including smoking cessation programmes, dietary counselling, and physical activity interventions tailored to those with MS.

Understanding Multiple Sclerosis

Multiple sclerosis is a chronic and unpredictable condition that affects the central nervous system. The disease occurs when the immune system mistakenly attacks the protective covering of nerve fibres, leading to inflammation and damage that disrupts communication between the brain and the rest of the body.

Symptoms of MS vary widely among individuals and may include:

• Fatigue – Debilitating tiredness that affects daily activities.
• Mobility Challenges – Weakness, muscle stiffness, and difficulties with balance and coordination.
• Cognitive Changes – Issues with memory, concentration, and problem-solving.
• Vision Problems – Blurred or double vision, or even vision loss in severe cases.

Currently, there is no cure for MS, but early diagnosis and treatment can help slow the disease’s progression and improve quality of life. Researchers continue to make significant progress towards developing more effective therapies and, ultimately, achieving a future free from MS.

Conclusion: A Call for Awareness and Action

This study underscores the importance of addressing modifiable lifestyle factors in the management of MS. While the condition itself remains incurable, interventions such as smoking cessation and weight management can make a meaningful difference in slowing disease progression and reducing disability risk.

Healthcare professionals and individuals with MS alike should take note of these findings and explore available support options for making healthier lifestyle choices. The research serves as a powerful reminder that even small changes can contribute to better long-term outcomes in the management of multiple sclerosis.

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Childhood obesity at cancer diagnosis leads to worse survival outcomes

A recent study published in Cancer has found that children who have obesity at the time of their cancer diagnosis experience significantly poorer survival outcomes compared to their peers without obesity. The findings indicate a notable reduction in both event-free survival (EFS) and overall survival (OS) rates, underscoring the need for further research into the underlying mechanisms and potential interventions.

Study Overview and Methodology

Researchers examined the relationship between obesity and cancer outcomes in children aged 2 to 18 years who were newly diagnosed with cancer. The study drew data from the Cancer in Young People in Canada database, covering cases from 2001 to 2020. A total of 11,291 children with cancer were included, with a median age at diagnosis of 7.6 years.

Among the participants, 55.0% were boys, and 10.5% were classified as having obesity at the time of diagnosis. The cohort included children with various types of cancer:

• Leukaemias (37.1%)
• Lymphomas (14.5%)
• Central nervous system (CNS) tumours (21.8%)
• Other solid tumours (26.6%)

Key Findings on Survival Outcomes

The study revealed a significant disparity in survival rates between children who had obesity at diagnosis and those who did not.

Event-Free Survival (EFS) Outcomes

• The median follow-up period for EFS was 4.5 years.
• The five-year EFS rate was 77.5% for children with obesity, compared to 79.6% for children without obesity (P = .04).
• Multivariable analyses confirmed that obesity at diagnosis was associated with a significantly increased risk of adverse outcomes, with an adjusted hazard ratio (aHR) of 1.16 (95% CI, 1.02-1.32; P = .02).

Overall Survival (OS) Outcomes

• The median follow-up period for OS was 4.7 years.
• The five-year OS rate was 83.0% for children with obesity, compared to 85.9% for those without obesity (P = .004).
• Multivariable analyses demonstrated a stronger association between obesity and reduced OS, with an adjusted hazard ratio (aHR) of 1.29 (95% CI, 1.11-1.49; P = .001).

Influence of Age and Gender

According to the researchers, the negative impact of obesity on survival outcomes was more pronounced in certain subgroups:

“The adverse impact of obesity on EFS and OS was more prominent in girls and in children younger than 10 years,” the researchers noted.

Interestingly, for children who continued to have obesity in the years following their cancer diagnosis, there was no significant difference in survival rates when compared to children without obesity. This finding was consistent across all cancer types within the study cohort.

Causes of Death and Obesity’s Role

The study also examined whether the causes of death differed between children with and without obesity. The results showed no significant differences in the primary causes of mortality, which included:

• Disease progression or relapse – 88.9%
• Treatment-related toxicity – 4.4%
• Other causes – 6.8%

Potential Mechanisms and Future Research

While the exact mechanisms by which obesity contributes to poorer cancer outcomes remain unclear, the researchers highlighted specific trends within subgroups of children diagnosed with acute lymphoblastic leukaemia (ALL) and CNS tumours:

“Although obesity at cancer diagnosis was independently associated with inferior survival across the entire cohort, this finding was likely driven by the trends detected in children with ALL and CNS tumours,” the researchers wrote.

This suggests that certain cancer types may be more affected by the presence of obesity, necessitating further investigation into biological and physiological factors at play.

Furthermore, the researchers emphasised the importance of understanding whether changes in body weight during treatment could impact survival outcomes:

“Further studies are needed to better characterise the pathophysiologic mechanisms linking obesity and survival in paediatric oncology. Furthermore, it is crucial to determine whether normalisation of weight during treatment positively affects cancer outcomes to inform future trial designs and supportive care interventions.”

Funding and Disclosures

This research received partial funding from the Fonds de Recherche du Québec–Santé. One of the study’s authors disclosed conflicts of interest; for full details, readers are encouraged to refer to the original publication.

Conclusion

This study provides compelling evidence that children with obesity at the time of a cancer diagnosis are at a significantly higher risk of experiencing inferior survival outcomes. While obesity did not appear to affect the cause of death, its association with poorer EFS and OS rates—particularly in younger children and girls—warrants urgent attention. Future research is essential to explore potential interventions, including weight management strategies during treatment, to improve survival outcomes in paediatric oncology.

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Study reveals teenagers with obesity consume more calories later in the day, highlighting the role of circadian rhythms in eating behaviours

A new study conducted by researchers at Mass General Brigham and the Warren Alpert Medical School of Brown University has found that adolescents with obesity tend to consume a greater proportion of their daily caloric intake later in the day compared to their peers with a healthy weight. The research sheds light on the influence of the body’s internal biological clock, or circadian system, in shaping eating behaviours and could have implications for future interventions in weight management and metabolic health.

The findings, published in the Proceedings of the National Academy of Sciences (PNAS), add to the growing body of evidence suggesting that meal timing, in addition to calorie consumption, plays a crucial role in overall health. Researchers sought to isolate the effects of the circadian system from external factors such as social cues, light exposure, and daily routines, allowing for a clearer understanding of how biological rhythms regulate food intake.

Investigating the Link Between the Circadian System and Eating Habits

“Going into this study, we knew that the circadian system affects hunger and metabolism. What remained unclear, however, was whether the circadian system—when isolated from influences of environmental and behavioural cycles, including the light, sleep, and activity cycles—directly influences food consumption,” said Frank A.J.L. Scheer, PhD, professor of Medicine and director of the Medical Chronobiology Program at Brigham and Women’s Hospital. “This study is the first to demonstrate that food intake itself is regulated by our internal body clock.”

To investigate this, researchers conducted an experiment involving 51 adolescents aged between 12 and 18 years, with an average age of 13.7 years. Participants were divided into three groups based on their body mass index (BMI): 24 individuals with a BMI in the healthy weight range, 13 classified as overweight, and 14 as having obesity.

To ensure that external influences such as light exposure and social schedules did not interfere with results, participants were placed on a carefully controlled routine in a dimly lit environment. They followed an artificial 28-hour sleep-wake cycle, which gradually shifted their biological clocks out of sync with the natural day-night cycle. The controlled setting removed access to natural light and external time cues, ensuring that any variations in eating habits were driven primarily by internal biological rhythms rather than external environmental factors.

During the study, participants were provided with six fixed meal opportunities during their wake period. They were allowed to eat as much as they wanted from a standardised menu, while researchers meticulously recorded the quantity of food consumed and the time at which it was eaten.

Findings Reveal Distinct Eating Patterns Based on Body Weight

The results demonstrated a clear trend across all groups: calorie consumption was lowest in the morning and increased as the day progressed, peaking in the late afternoon and early evening. However, there was a significant difference in eating patterns among participants based on body weight. Adolescents in the overweight and obesity groups consumed substantially more calories later in the day compared to those with a healthy weight.

These findings suggest that biological rhythms may play a role in promoting late-day eating, particularly in individuals with higher body weight. The study raises important questions about how circadian misalignment—such as eating at biologically suboptimal times—could impact long-term metabolic health and contribute to weight gain over time.

Potential Implications for Adolescent Health and Future Interventions

Adolescence is a critical period for growth and metabolic regulation, making it essential to understand how sleep-wake cycles and circadian rhythms influence eating behaviours.

“The critical nature of adolescent development to set the stage for a lifetime of health highlights the need to understand the roles played by sleep/wake and circadian timing processes for eating behaviour,” said Mary A. Carskadon, PhD, lead investigator of the study from the Warren Alpert Medical School. “The knowledge gained here opens a door to potential interventions that can enhance teen health moving forward.”

While the study provides strong evidence of an association between circadian rhythms, eating habits, and weight status, it does not establish whether altered meal timing contributes to obesity or if pre-existing obesity influences circadian-driven eating patterns. Further research is needed to determine whether adjusting the timing of meals—such as encouraging earlier eating or aligning meals more closely with the body’s natural rhythms—could play a role in supporting weight management and metabolic health in young people.

Given the growing prevalence of obesity among adolescents, understanding the biological underpinnings of eating behaviours could pave the way for targeted strategies to improve health outcomes. Future studies will explore whether interventions that shift meal timing can mitigate the risk of obesity and related metabolic conditions, providing a potential avenue for improving long-term health in young people.

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Healthy eating habits in adolescents start with the foods available at home

A recent study published in the Journal of Nutrition Education and Behavior, an Elsevier journal, provides compelling evidence that the home food environment has a more significant impact on adolescent dietary behaviours than the availability of fast-food and convenience stores in the surrounding neighbourhood. This research contributes to the ongoing conversation about adolescent nutrition and obesity by highlighting the critical role that food availability within the home plays in shaping young people’s eating habits.

The study, conducted as a cross-sectional analysis, aimed to determine the relative influence of home and neighbourhood food environments on adolescent dietary choices. Researchers examined whether the presence of healthier food options at home, such as fruits and vegetables, encouraged better eating habits while also investigating the impact of the density of fast-food outlets and convenience stores in the local area. The findings underscore the importance of household food availability as a key factor in promoting a nutritious diet, reinforcing the notion that interventions targeting the home environment may be more effective in improving adolescent nutrition than efforts aimed at modifying broader neighbourhood food landscapes.

Key Findings: The Home Environment as a Major Dietary Influence

The study’s findings reveal that the availability of fruits and vegetables at home is strongly associated with healthier eating patterns among adolescents. Greater access to these nutrient-dense foods was linked to increased consumption of fruits and vegetables, higher overall diet quality (as measured by the Healthy Eating Index), and a reduction in the intake of fast food and other less nutritious options.

Conversely, the presence of energy-dense, nutrient-poor foods—such as sweets and high-fat snacks—was correlated with higher consumption of these items among adolescents. This suggests that the types of foods stocked in the home can either support or hinder efforts to establish healthy eating patterns during a critical stage of development.

The study also found that while the neighbourhood food environment does play a role, its impact is comparatively less pronounced. For instance, a higher number of fast-food outlets in an adolescent’s local area was associated with increased consumption of sugary beverages. However, an unexpected finding was that the presence of more convenience stores in the neighbourhood was linked to a greater intake of nutrient-dense foods. This may be due to the availability of certain healthier options in these stores, although further research is needed to fully understand this relationship.

Methodology: A Comprehensive Approach to Studying Adolescent Nutrition

To conduct this research, the study analysed data from 204 adolescents living in Nebraska. The researchers used a combination of validated questionnaires, geographic information systems (GIS) mapping, and dietary recall assessments to evaluate the availability of food at home, the density of fast-food and convenience store retailers in participants’ neighbourhoods, and the overall quality of dietary intake.

The study employed advanced hierarchical regression analyses to isolate the independent contributions of home and neighbourhood food environments on adolescent dietary outcomes. Data collection included both in-laboratory assessments and follow-up dietary recalls to capture eating behaviours across different contexts, ensuring a more nuanced understanding of how these environments shape food choices.

Lead author Saira Sarwar, MA, from the Department of Psychology at the University of Nebraska-Lincoln, emphasised the importance of these findings, stating, “These findings underscore the importance of targeting the home food environment as a modifiable factor in dietary interventions for adolescents.”

Implications for Public Health and Future Research

The study’s findings have significant implications for public health strategies aimed at improving adolescent nutrition and reducing the risk of obesity. Given the strong association between home food availability and dietary quality, interventions that encourage parents and caregivers to provide more fruits, vegetables, and other nutrient-dense foods at home could have a substantial impact. Public health campaigns and nutrition education programmes may be most effective when they focus on empowering families to create a healthier home food environment rather than solely addressing external factors such as the presence of fast-food outlets.

While the research provides valuable insights, further studies are needed to confirm these findings and explore additional factors that may influence adolescent dietary behaviours. Future research could investigate how economic, cultural, and psychological factors shape food purchasing decisions within households and how these elements interact with the broader food environment. Additionally, longitudinal studies tracking dietary patterns over time could offer deeper insights into how home and neighbourhood influences evolve and affect long-term health outcomes.

Conclusion

This study highlights the critical role of the home food environment in shaping adolescent dietary habits, reinforcing the idea that interventions aimed at improving food choices within the household may be more impactful than those focused solely on modifying the external food landscape. As concerns over adolescent obesity and poor dietary habits continue to grow, these findings provide valuable guidance for health professionals, policymakers, and families seeking effective strategies to promote healthier eating behaviours among young people.

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