Rising obesity prevalence may have altered perceptions of healthy body weights, study suggests
A concerning trend has emerged, revealing that an increasing number of overweight teenagers do not perceive themselves as being too heavy. This phenomenon raises alarms as it may lead to detrimental lifestyle choices, warn scientists. The trend of underestimating body weight was found to be particularly prevalent among girls, according to a peer-reviewed study.
The study suggests that the rising prevalence of obesity and the emergence of body trends idealising an athletic, muscular physique may contribute to teenagers underestimating their weight and becoming resistant to adopting healthy diet and exercise habits. However, the researchers acknowledge that other factors, including body image, dieting, changing eating patterns, and migration, may also play a role in these shifting perceptions over time.
Conducted by the International Health Behaviour in School-Aged Children, the study surveyed 11 to 15-year-olds between 2002 and 2018, analysing trends in body weight perception while considering age, gender, and family socioeconomic status. The survey encompassed over 745,000 adolescents from 41 countries across Europe and the United States. These findings are particularly significant for the UK, where more than a third of teenagers have either overweight or obesity.
Lead author of the study, Dr. Anouk Geraets from the Department of Social Sciences at the University of Luxembourg, emphasised the potential impact of body weight perception during this impressionable age on teenagers’ lifestyle choices, including their food consumption and exercise habits. Dr. Geraets expressed concern regarding the trend of fewer adolescents perceiving themselves as overweight, as this could undermine efforts to address the escalating obesity levels among this age group. Teenagers who underestimate their weight may not recognize the need to lose excess weight and may consequently make unhealthy lifestyle choices.
The study revealed an increase in underestimation of weight status and a decrease in overestimation over time, with girls being more susceptible to these perceptions than boys. Scientists worry that shifting trends in perception could diminish the effectiveness of public health interventions targeting young people.
Dr. Geraets emphasised the clinical and public health implications of the study. While the increase in accurate weight perception and the decrease in overestimation may have a positive impact by reducing unnecessary and unhealthy weight loss behaviours among adolescents, the rise in underestimation highlights the need for interventions to strengthen accurate weight perception. Further research is necessary to understand the underlying factors driving these trends and to develop effective public health interventions.
The study’s findings were published in the journal Child and Adolescent Obesity, shedding light on the urgent need to address teenagers’ misperceptions of their weight in order to promote healthier lifestyles and combat the growing obesity crisis among this age group.
Study challenges belief that moderate alcohol consumption shields against obesity and type 2 diabetes
Moderate alcohol consumption does not provide protection against conditions such as obesity and type 2 diabetes, according to a recent study, challenging the long-debated notion of potential health benefits associated with light to moderate drinking.
The study investigated whether modest alcohol intake had any positive effects on health—a subject that has divided experts. Researchers analysed data on alcohol consumption from over 400,000 participants and discovered a higher risk of obesity and type 2 diabetes among individuals who consumed more than 14 drinks per week. Notably, this link was more pronounced in women than in men.
Dr. Tianyuan Lu of McGill University in Québec commented on the findings, stating, “Previous research has suggested that moderate drinkers may be less susceptible to developing obesity or diabetes compared to non-drinkers and heavy drinkers. However, our study indicates that even light-to-moderate alcohol consumption, defined as no more than one standard drink per day, does not safeguard against obesity and type 2 diabetes in the general population.”
The study’s results revealed that heavy drinking was associated with increased measures of obesity, such as body mass index, waist-to-hip ratio, and fat mass, as well as an elevated risk of type 2 diabetes.
Importantly, the study did not find any evidence of improved health outcomes related to moderate alcohol consumption in individuals who consumed seven or fewer alcoholic drinks per week.
Dr. Lu concluded by highlighting the significance of the research in promoting awareness of the risks associated with alcohol consumption. The study’s findings aim to inform future guidelines and recommendations regarding alcohol use, with the hope of encouraging healthier behaviours as alternatives to drinking.
For further details, refer to the full study published in JCEM.
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UK’s soaring liver cancer death rate blamed on alcohol and obesity
Liver cancer deaths in the UK have seen a staggering 40% increase over the past decade, making it the fastest-growing cause of cancer-related fatalities in the country, warns the British Liver Trust. Calling attention to the alarming rise, the charity is urging immediate measures to address the “carcinogenic effects” of inexpensive alcohol and unhealthy food.
Pamela Healy, CEO of the British Liver Trust, identifies alcohol and obesity as the key drivers behind the surge in liver cancer cases and deaths. She stresses the need for government intervention to combat these issues, asserting that such action can create a healthier environment for all. Healy emphasises the urgency of addressing the accessibility and affordability of unhealthy food, often priced significantly lower than nutritious alternatives.
This call for action comes amidst delays in implementing regulations that would prohibit supermarket multi-buy deals on high-fat, high-sugar, or high-salt foods. The Association of Directors of Public Health has also urged ministers to introduce minimum unit pricing on alcohol, following Scotland’s successful implementation of a minimum price of 50p per unit in 2018.
The British Liver Trust has submitted evidence to the parliamentary health and social care committee’s inquiry into future cancer care, focusing on innovative approaches to diagnosis and treatment. In addition to advocating for earlier detection and improved access to effective therapies, the charity emphasises the importance of prevention. Liver disease, a significant risk factor for liver cancer, can be reversed through lifestyle modifications, including reduced alcohol consumption and weight loss.
The submission by the British Liver Trust emphasises the need for upstream interventions to mitigate the carcinogenic impact of an unhealthy food and beverage environment. The charity cites evidence indicating that population-wide measures regulating the affordability and accessibility of alcohol and unhealthy food are more effective in reducing disease burden and addressing health inequalities than individual behaviour change alone.
The charity calls for a comprehensive alcohol strategy that tackles promotions and affordability. It highlights the fact that alcohol is classified as a group 1 carcinogen, known to cause at least seven types of cancer. Data from Cancer Research reveals that liver cancer mortality rates per 100,000 people in the UK have risen from 6.4 in 2007-2009 to 9.3 in 2017-2019. Primary liver cancer has one of the lowest survival rates among all cancers.
The British Liver Trust emphasises the need for enhanced surveillance of high-risk groups with liver disease to enable early diagnosis and improve survival rates. Additionally, the charity advocates for increased investment in liver cancer research.
The UK government is facing mounting pressure to take more effective action to combat obesity. Danone UK and Ireland, one of the country’s major food companies, recently suggested that the government should consider taxing products high in fat, sugar, or salt to tackle the obesity crisis.
In response to the inquiry, the Department of Health and Social Care affirms its commitment to diagnosing 75% of cancers at stages 1 and 2 by 2028. The department outlines its interventions, including community health liver checks for those at high risk of cirrhosis, with a particular focus on deprived communities.
A spokesperson from the Department of Health and Social Care highlights ongoing efforts to encourage healthier food and drink choices and tackle obesity. Recognising that obesity costs the NHS approximately £6.5 billion per year and is the second leading cause of cancer, the spokesperson highlights initiatives such as calorie labelling in restaurants, cafes, and takeaways to empower individuals to make informed lifestyle choices.
The spokesperson further notes that the NHS has witnessed record numbers of cancer patients in recent years, with earlier-stage diagnoses becoming more prevalent. To support this, the government is strengthening the cancer workforce and has published the first-ever Long-Term Workforce Plan, backed by over £2.4 billion, aiming to deliver the most extensive training expansion in NHS history over the next 15 years.
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New study links obesity to 18 types of cancer, including leukaemia and lymphoma
In a concerning development, a recent study has established a direct connection between excess body weight and an elevated risk of developing multiple types of cancer. While previous research had identified 13 cancers associated with overweight or obesity, this groundbreaking study expands the list to include 18 different forms of the disease. The findings highlight the urgent need for a reevaluation of the impact of overweight and obesity on cancer rates and emphasise the significance of weight management from an early age.
The study, conducted by researchers in Catalonia, Spain, examined the electronic health records of over 2.6 million individuals aged 40 or older who were initially cancer-free. Surprisingly, within a span of just nine years, more than 225,000 participants received a cancer diagnosis. The researchers meticulously analysed the data, paying close attention to individuals with a body mass index (BMI) of 25 or greater, indicative of having overweight or obesity.
Published in Nature Communications, the study’s results reveal a troubling correlation between a BMI of 25 or higher and an increased susceptibility to 18 distinct types of cancer. What is particularly noteworthy is that the risk of cancer development begins as early as 18 years old. Furthermore, individuals who were overweight during their early adulthood (between the ages of 18 and 40) faced a significantly higher risk of developing cancer. The risk further intensified for those who struggled with excess weight for extended periods and those who experienced severe obesity in their youth.
Dr. Heinz Freisling, a co-author of the study, emphasised the implications of these findings, urging a reassessment of the current estimation of the cancer burden associated with overweight and obesity. It is highly likely that the actual burden is underestimated due to these newly discovered connections.
This study adds to the growing body of evidence highlighting the long-term health risks stemming from childhood obesity, including its impact on cognitive function and brain structure. Additionally, the researchers identified several types of cancer that are now linked to excess weight, including leukaemia, non-Hodgkin lymphoma, head and neck cancers, and bladder cancer.
Previously recognised connections between excess weight and cancer include adenocarcinoma of the oesophagus, postmenopausal breast cancer, colon and rectal cancer, uterine cancer, gallbladder cancer, gastric cardia cancer, kidney cancer, liver cancer, ovarian cancer, pancreatic cancer, thyroid cancer, meningioma (a type of brain cancer), and multiple myeloma, as reported by the Centers for Disease Control and Prevention (CDC).
Dr. Panagiota Mitrou, director of research, policy, and innovation at the World Cancer Research Fund, emphasised the public health implications of this comprehensive study. The new findings establish connections between overweight/obesity and additional cancers, such as leukaemia and non-Hodgkin lymphoma. Maintaining a healthy weight throughout life, starting from early adulthood, emerges as one of the most critical preventive measures against cancer.
The study underscores the need for proactive public health measures, focusing on early prevention and weight management strategies to reduce the incidence of these cancers and promote overall well-being. By prioritising healthy weight maintenance, individuals can significantly mitigate their risk of developing various types of cancer and safeguard their long-term health.
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Exercise and weight loss combination amplifies battle against obesity and prediabetes
Groundbreaking research conducted at Washington University School of Medicine in St. Louis reveals the tremendous impact of combining regular exercise with a 10% body weight loss in combating obesity and prediabetes. The study found that this combination more than doubles insulin sensitivity compared to weight loss alone, reducing the risk of developing Type 2 diabetes and coronary heart disease.
The researchers initially knew that modest weight loss improves insulin sensitivity, and exercise alone has limited efficacy in aiding individuals with obesity and prediabetes in shedding pounds. However, they were astonished to discover the profound effect that combining a consistent exercise regimen with a 10% reduction in body weight can have on insulin sensitivity.
Published in the journal Nature Metabolism, the findings shed light on the crucial role of exercise in improving overall health outcomes for individuals struggling with obesity and prediabetes.
Dr. Samuel Klein, the senior investigator and director of the Center for Human Nutrition, explained the significance of the study’s results: “Insulin resistance is a major factor that causes Type 2 diabetes, nonalcoholic fatty liver disease, and abnormal blood lipids in people with obesity. We’ve shown that combining exercise with weight loss causes a marked improvement in whole-body insulin sensitivity, thereby lowering the risk of developing diabetes and treating obesity-related metabolic diseases to a much greater degree than is possible with weight loss alone.”
The study involved 16 participants with a body mass index (BMI) ranging from 30 to 49, indicating obesity. All participants had prediabetes and demonstrated medical evidence of insulin resistance.
Eight participants underwent a diet-only intervention, resulting in a 10% body weight loss. The other eight individuals followed the same dietary plan but also engaged in supervised exercise sessions multiple times per week.
Dr. Klein highlighted the significance of their findings: “The data from most studies show that exercise has very little effect on body weight in people with obesity… Our study involved detailed analyses of metabolic changes in muscle and body fat before and after a 10% weight loss in people who lost weight with diet therapy alone and in those who lost the same amount of weight with diet therapy plus supervised exercise training. The results demonstrate that the benefits of combining exercise with weight loss are considerable.”
With over 37 million Americans living with diabetes and more than 40% of the population grappling with obesity, which is a significant contributor to diabetes cases, the study’s findings have far-reaching implications. Approximately 96 million adults in the United States, or one in three, are estimated to have prediabetes.
Dr. Klein emphasised the crucial role of exercise in weight management therapy, stating, “The metabolic benefits we found in this study demonstrate the profound reasons why exercise should always be included in weight-management therapy.”
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Revitalising weight loss: The miraculous power of “beige fat” in reversing age-related weight gain
Discovering the ability to activate the body’s own fat-burning mechanisms and counteract age-related metabolic changes might seem like an unattainable dream, but researchers at Cornell University’s Division of Nutritional Sciences are working towards making it a reality. Their recent study explores the potential of a specific type of fat cells known as “beige fat” to reverse the effects of a slowing metabolism.
In mammals, including humans, two main types of fat exist: white adipose tissue (WAT), which stores excess calories, and brown adipose tissue (BAT), which burns calories to generate heat and regulate body temperature. The study sheds light on the therapeutic possibilities of a third type of fat called beige fat, a subtype of WAT. Beige fat shares characteristics with both white and brown fat, possessing thermogenic properties similar to brown fat and the ability to regulate blood sugar levels and reduce fatty acids associated with conditions like arterial hardening and heart disease.
The formation of beige fat occurs when adipose progenitor cells, a type of stem cell found within white fat, are stimulated by prolonged exposure to cold temperatures. However, as individuals age, their response to this stimulus weakens, leading to an imbalance favouring the production of white fat.
“Seasonal changes in beige fat occur in young humans, but an older person would have to stand outside in the snow in their underwear to achieve those same effects,” explains Dan Berry, an assistant professor in the Division of Nutritional Sciences at Cornell University.
Previous research by Berry revealed that the ageing process inhibits the formation of beige fat cells in response to cold temperatures.
The study’s lead author, Abigail Benvie, a doctoral student researcher in Berry’s lab, explains that the ultimate goal of their research is to find ways to stimulate metabolic pathways without subjecting individuals to prolonged cold exposure. Researchers successfully suppressed this pathway in ageing mice and stimulated the production of beige fat cells in areas where only white fat would typically form.
This research not only offers potential solutions for age-related weight gain and associated health conditions but also provides insights into the molecular mechanisms underlying beige fat formation. The study’s co-authors, including graduate students Derek Lee, Benjamin M. Steiner, and Siwen Xue, as well as Yuwei Jiang from the University of Illinois at Chicago, plan to further investigate the identified pathway and explore other molecular regulators of beige fat formation. With a $2.2 million, five-year grant from the National Institutes of Health, Berry’s lab aims to deepen our understanding of how these regulators change in levels and activity during the ageing process.
The study, published in the journal Nature Communications, represents a significant step forward in harnessing the potential of beige fat to combat age-related weight gain and improve metabolic health.
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Family-focused approach in paediatric primary care proves effective for child weight loss
A groundbreaking family-based treatment for childhood obesity, developed by researchers at the University at Buffalo (UB), has demonstrated significant success in a multicenter study conducted in paediatric primary care settings. Previously available only in specialised clinics, this evidence-based treatment has now been implemented for the first time in four U.S. cities, targeting children aged 6-12 and their parents.
Published in the Journal of the American Medical Association, the study reveals that family-based treatment conducted in paediatricians’ offices leads to improved weight-loss outcomes not only for the treated child and parent but also for untreated siblings. The research, supported by the National Heart, Lung and Blood Institute, emphasises that the healthy behaviours promoted during the treatment extend beyond the immediate family members, potentially improving the overall health of the entire family.
In the study, three times as many children in the treatment group (27%) experienced a clinically meaningful reduction in median body mass index (BMI) compared to the usual care group (9%). These improvements in weight correlated with enhanced cardiometabolic outcomes, such as blood pressure, lipids, and glucose regulation. The success of this novel family-focused treatment, pioneered by senior author Leonard H. Epstein, has significant implications for the long-term health and well-being of the treated children.
The family-based treatment program involves the implementation of eating and activity plans, education in parenting and behavioural techniques, and the facilitation of support for positive behaviour changes within both the family and peer environments. In individualised sessions, parents and children are seen together, reviewing self-monitored eating and activity levels, treatment manuals, handouts, and setting goals for weight and behaviour.
The randomised clinical trial enrolled 452 children aged 6 to 12, with one parent, in primary care practices across Buffalo, Rochester, Columbus, and St. Louis. Half of the children received family-based treatment, while the other half received usual care. Notably, the treatment demonstrated positive outcomes across racial and ethnic backgrounds.
Children receiving family-based treatment showed a significant difference in percent over median BMI compared to those receiving usual care, with a reduction of 6.48%. Furthermore, parents experienced a reduction of 3.97% in BMI, and untreated siblings who were overweight had a reduction of 5.38%. These changes in BMI among family members were interrelated, suggesting that the treatment fosters the modelling of healthy behaviours and facilitates real change in the shared family environment.
The success of this behavioural intervention underscores the growing need for similar treatments in paediatric primary care. The study authors emphasise the necessity for “coaches” in primary care settings who can provide support for obesity treatment and address various behavioural issues, including anxiety, depression, and eating disorders.
The implementation of this family-focused approach not only ensures the immediate health of children but also equips them with lifelong healthy practices. The study’s positive outcomes highlight the potential for transforming paediatric primary care into a hub for comprehensive behavioural interventions, addressing a wide range of health-related concerns.
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Study reveals obesity as a precursor to mental disorders across all ages
A recent study conducted by the Medical University of Vienna in collaboration with the Complexity Science Hub Vienna has uncovered that individuals suffering from obesity face an elevated risk of developing various mental disorders across all age groups. Interestingly, the study reveals that women are more susceptible than men to most of these disorders. The research findings were published in Translational Psychiatry, a renowned scientific journal.
The researchers meticulously analysed a comprehensive dataset, encompassing all inpatient hospitalisations in Austria between 1997 and 2014. The aim was to ascertain the relative risks of coexisting diseases in individuals with obesity and to pinpoint any statistically significant variations between genders. The data illustrated that an obesity diagnosis markedly heightens the likelihood of developing an array of mental disorders, including depression, nicotine addiction, psychosis, anxiety, eating disorders, and personality disorders.
Michael Leutner, who headed the study and is part of the Department of Internal Medicine II at MedUni Vienna, asserted, “The findings highlight the imperative need for increased vigilance toward psychiatric diagnoses in patients with obesity and engaging specialists early on if necessary.”
Elma Dervic, the co-first author of the study from the Complexity Science Hub, expounded on the innovative approach adopted to discern which illness typically manifested before or after an obesity diagnosis. “This novel method enabled us to identify trends and common patterns in the onset of diseases,” Dervic explained. The study revealed that, with the exception of disorders in the psychosis spectrum, obesity was likely to be diagnosed before the emergence of any psychiatric condition.
Contrary to a widely-held belief among physicians that psychopharmacological medications were responsible for the connection between mental disorders and obesity, the study suggests otherwise. “While this might hold true for schizophrenia, our data does not corroborate this for depression or other mental disorders,” elucidated Alexander Kautzky, the first author from the Department of Psychiatry and Psychotherapy at MedUni Vienna. However, it remains uncertain whether obesity directly impacts mental health or if early stages of psychiatric disorders are frequently overlooked.
Notably, the study found women to be more predisposed to nearly all mental disorders, except for schizophrenia and nicotine addiction. Approximately 16.66% of men with obesity were found to have nicotine addiction compared to just 8.58% of women with obesity. Conversely, the rate of diagnosed depression was nearly threefold higher in women with obesity (13.3% in women with obesity compared to 4.8% in women who did not have obesity) than in men with obesity (6.61% in men with obesity compared to 3.21% in men who did not have obesity).
With over 670 million individuals affected by obesity globally, it is well-established that obesity contributes to metabolic disorders and severe cardio-metabolic complications such as diabetes mellitus, arterial hypertension, and dyslipidemia. The revelation that obesity is frequently a precursor to serious mental disorders underscores its significance as a health risk factor, particularly for younger populations where the risk is most pronounced.
Consequently, the researchers stress the urgency for comprehensive mental health screening amongst patients with obesity to enable timely preventive measures or the provision of appropriate treatment.
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NHS England to open 10 more clinics for children with obesity
In response to the alarming rise in childhood obesity, NHS England has announced plans to launch 10 additional clinics specifically tailored to the needs of children with obesity. This expansion comes as part of a concerted effort to combat the escalating numbers of children and young people struggling with obesity and its associated health complications.
According to recent data released by NHS England, hospital admissions for children with obesity have soared in the past decade, with 9,431 admissions recorded in the year 2021/22, compared to just 3,370 in 2011/12.
Targeting children as young as two, the specialised clinics will offer intensive support to children with severe obesity and their families. It is estimated that around 3,000 children and teenagers, ranging from 2 to 18 years of age, will benefit from these services.
These clinics are designed to address not just the physical aspects of obesity, but also the underlying psychological and social factors. The support provided will encompass tailored care packages which are developed in collaboration with the child’s family. These packages may include diet and nutrition plans, mental health support, and personalised coaching, among other services.
This expansion, backed by an £18 million investment, will bring the total number of specialised obesity clinics for children in England to 30. The project is set to be rolled out over the next two years.
Amanda Pritchard, Chief Executive of NHS England, is slated to formally announce the opening of the new clinics at the NHS ConfedExpo conference in Manchester. In her address, she is expected to underscore the urgent need for such initiatives, stating, “Obesity can lead to a myriad of severe illnesses including cancer and diabetes, not only putting tremendous strain on the NHS but also exacting a devastating toll on individuals and their families. Inaction is not an option. These new clinics will offer a comprehensive, compassionate and tailored approach to support thousands of young individuals and their families.”
Professor Simon Kenny, NHS England’s National Clinical Director for Children and Young People, emphasised the holistic approach of these clinics. He noted that obesity can have far-reaching effects on every organ system, leading to long-term complications like premature mortality, type 2 diabetes, strokes, early joint replacements, and mental health issues. “By addressing obesity and its root causes in a manner that respects and accommodates the unique circumstances of each child and young person, these clinics will play a pivotal role in helping them lead healthier, more fulfilling lives. Our commitment to supporting the physical and mental health of as many children and young people as possible is unwavering,” he added.
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Prenatal exposure to durable ‘forever chemicals’ may contribute to childhood obesity, study finds
A recent study backed by federal funding suggests that exposure to per- and polyfluoroalkyl substances (PFAS), also known as ‘forever chemicals,’ during pregnancy is associated with higher body mass indices (BMIs) and increased risks of obesity in children.
The study, spearheaded by Brown University researchers, adds to the growing body of evidence that the consequences of exposure to PFAS begin even before birth, potentially predisposing children to health challenges later in life.
PFAS are a group of chemicals used in a variety of products such as water-repellent textiles, personal care items, firefighting foams, food packaging, and medical products, due to their oil and water-resistant properties. Their extremely stable structure means they can persist in the environment for thousands of years, earning them the nickname ‘forever chemicals’.
The research was carried out under the Environmental Influences on Child Health Outcomes (ECHO) program at the National Institutes of Health, employing a more extensive dataset compared to previous studies. Lead author Yun “Jamie” Liu, a postdoctoral research associate in epidemiology at the Brown University School of Public Health, stated that the study analysed eight research cohorts with varying demographics across the United States, making the findings more representative of the general population.
Using data collected over two decades involving 1,391 children aged between 2 and 5 years and their mothers, who were part of ECHO research sites in California, Illinois, Massachusetts, Colorado, New Hampshire, Georgia, and New York, the study examined blood samples taken from mothers during pregnancy. The levels of seven different PFAS were analysed, and children’s body mass indices were calculated.
The study revealed a correlation between higher levels of PFAS in the mothers’ blood during pregnancy and slightly elevated BMIs in children. This increased risk of obesity was consistent among both male and female children. Notably, these associations were evident even at relatively low levels of PFAS exposure.
Joseph Braun, the study’s senior author and a professor of epidemiology at Brown’s School of Public Health, highlighted the significance of these findings in contemporary contexts. He noted that despite the reduction in PFAS usage as manufacturers have phased them out due to health concerns, exposure during pregnancy could still pose risks. “This implies that children may continue to face risks of PFAS-related health issues,” Braun added.
Braun has been engaged in several studies examining the effects of PFAS on children’s health for over a decade. He believes that this kind of research can inform environmental policies and safety guidelines.
The research team aims to continue their investigations by exploring the relationships between maternal PFAS exposure and obesity-linked health outcomes in older children, eventually expanding to adolescents and adults.
The study received support from the ECHO program, the National Institute of Environmental Health Sciences, and the National Institute of General Medicine Sciences.
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Obesity alters brain function, hindering weight loss maintenance, study finds
Researchers from Amsterdam UMC and Yale University have recently unveiled a ground-breaking link between obesity and altered brain responses to nutrients. Their study indicates that obesity leads to reduced dopamine release and diminished nutrient-sensing activity in the brain. Worryingly, these changes persist even after weight loss, potentially explaining why maintaining weight loss is so challenging for many.
The research, published in Nature Metabolism, highlights that the brain’s responses to certain nutrients are impaired in individuals with obesity and don’t show improvement even after shedding weight.
Mireille Serlie, the lead researcher and Professor of Endocrinology at Amsterdam UMC, elaborates on the implications of the study, “Our results point toward enduring alterations in the brain among individuals with obesity, which could have a substantial impact on eating behaviour. We observed that, compared to individuals of normal weight, those with obesity exhibited lower dopamine release in a brain region that plays a pivotal role in the motivation associated with food consumption. Dopamine is crucial for the rewarding aspects of eating. Moreover, those with obesity demonstrated diminished brain activity in response to the infusion of nutrients into the stomach. Collectively, these results suggest that the brain’s ability to sense nutrients in the stomach and gut, or to process nutritional signals, is compromised in obesity, which may have significant repercussions on food intake.”
The regulation of food consumption is dependent on a complex interplay of metabolic and neural signals among the brain and various organs, such as the gut, as well as nutritional signals in the blood. This intricate network governs hunger and satiety sensations, regulates food intake, and controls the motivation to seek food. Though advances have been made in understanding these processes in animals, especially regarding metabolic diseases like obesity, less is known about the human mechanisms, mainly due to challenges in creating experimental setups within clinical settings that can elucidate these processes.
Addressing this knowledge gap, Serlie and her team, including colleagues from Yale, conducted a meticulously designed controlled trial. The study involved 30 participants with obesity and 30 of normal weight. It entailed infusing specific nutrients directly into the participants’ stomachs while simultaneously assessing their brain activity using MRI scans and monitoring dopamine release with SPECT scans.
The study discovered that while participants of normal weight showed distinct patterns of brain activity and dopamine release in response to nutrient infusion, these responses were significantly weakened in those with obesity. Furthermore, even after achieving a 10% body weight loss through a 12-week diet, the brain responses in individuals with obesity did not improve. This finding suggests that obesity induces long-term adaptations in the brain that persist even after weight loss.
“The enduring nature of these brain alterations, which do not reverse even after weight loss, might elucidate why so many individuals tend to regain weight following initial successful weight loss,” Serlie concludes.
This discovery brings to light the intricate challenges faced by those striving to lose weight and maintain the loss, suggesting that strategies need to address not only the physical aspects but also the neurological factors entangled with obesity.
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Elevated risk of stillbirth among pregnant women with obesity
Obesity before pregnancy appears to considerably increase the likelihood of perinatal mortality, suggests a mediation analysis study.
The study, involving 392,820 women, revealed that women with obesity before pregnancy had a 55% increased risk of perinatal mortality – defined as stillbirth or neonatal death prior to hospital discharge, as informed by Jeffrey Bone, a PhD candidate at the University of British Columbia, Vancouver, along with his team.
The study, published in PLoS One, also showed that even women who had overweight before pregnancy exhibited a 22% increased risk of perinatal mortality compared to women who had a normal BMI.
The largest mediator between obesity and perinatal death was the gestational age at delivery, which accounted for 63.1% of the association, according to the researchers. Adjustments were made for factors such as chronic hypertension, smoking, alcohol and substance use, previous stillbirths or preterm births, parity, maternal age, year of birth, chronic diseases, and asthma during the study.
Bone commented that women with obesity often face higher neonatal death rates and stillbirths, and the exact reasons for this remain to be fully deciphered. He said, “Our aim was to determine whether this could be partially attributed to their pregnancies ending earlier than those of women with normal weight.”
Even though these findings were anticipated, Bone believes there are still numerous questions that warrant further investigation. The team has recommended future studies to identify the specific factors contributing to higher pre-pregnancy BMI and their impact on perinatal mortality, such as inactive lifestyle, high calorie diet, and medical or genetic conditions.
The study emphasises the necessity for healthcare professionals to pay extra attention to pregnant women with obesity to prevent stillbirth and neonatal death, especially in the second trimester. Bone emphasised the complexity of the reasons for increased risks, which include maternal complications leading to preterm birth more frequently in obese women, as well as foetal and placental reasons. He stressed that more research is needed to better devise interventions for women with high pre-pregnancy BMI.
The research team evaluated data from 547,401 single live births and stillbirths in British Columbia between 2004 and 2017. The study excluded data from late terminations and women with births before 20 weeks of gestation.
Of the 392,820 women included in the study, 12.8% (50,352) were classified as having obesity, 20.6% (81,065) as having overweight, 60.6% (237,726) as normal weight, and 6.0% (23,677) as underweight. These pre-pregnancy weight categories were self-reported based on the following BMI ranges: underweight (<18.5), normal (18.5 to <25), overweight (25 to <30), and obese (BMI 30+).
The study found that, compared to women with normal BMI, those with obesity were more likely to have multiple births, smoke during pregnancy, suffer from chronic and gestational hypertension or diabetes, and have a history of caesarean delivery.
In terms of preterm birth rates, a pattern emerged correlating higher rates with an increased BMI: 7.3% among women with a normal BMI, 8.1% among overweight women, and 9.7% among women with obesity, according to the researchers.
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