Total energy expenditure is repeatable in adults but not associated with short-term changes in body composition

Definition and diagnostic criteria of clinical obesity

Current BMI-based measures of obesity can both underestimate and overestimate adiposity and provide inadequate information about health at the individual level, which undermines medically-sound approaches to health care and policy. This Commission sought to define clinical obesity as a condition of illness that, akin to the notion of chronic disease in other medical specialties, directly results from the effect of excess adiposity on the function of organs and tissues. The specific aim of the Commission was to establish objective criteria for disease diagnosis, aiding clinical decision making and prioritisation of therapeutic interventions and public health strategies. To this end, a group of 58 experts—representing multiple medical specialties and countries—discussed available evidence and participated in a consensus development process. Among these commissioners were people with lived experience of obesity to ensure consideration of patients’ perspectives. The Commission defines obesity as a condition characterised by excess adiposity, with or without abnormal distribution or function of adipose tissue, and with causes that are multifactorial and still incompletely understood. We define clinical obesity as a chronic, systemic illness characterised by alterations in the function of tissues, organs, the entire individual, or a combination thereof, due to excess adiposity. Clinical obesity can lead to severe end-organ damage, causing life-altering and potentially life-threatening complications (eg, heart attack, stroke, and renal failure). We define preclinical obesity as a state of excess adiposity with preserved function of other tissues and organs and a varying, but generally increased, risk of developing clinical obesity and several other non-communicable diseases (eg, type 2 diabetes, cardiovascular disease, certain types of cancer, and mental disorders). Although the risk of mortality and obesity-associated diseases can rise as a continuum across increasing levels of fat mass, we differentiate between preclinical and clinical obesity (ie, health vs illness) for clinical and policy-related purposes. We recommend that BMI should be used only as a surrogate measure of health risk at a population level, for epidemiological studies, or for screening purposes, rather than as an individual measure of health. Excess adiposity should be confirmed by either direct measurement of body fat, where available, or at least one anthropometric criterion (eg, waist circumference, waist-to-hip ratio, or waist-to-height ratio) in addition to BMI, using validated methods and cutoff points appropriate to age, gender, and ethnicity. In people with very high BMI (ie, >40 kg/m2), however, excess adiposity can pragmatically be assumed, and no further confirmation is required. We also recommend that people with confirmed obesity status (ie, excess adiposity with or without abnormal organ or tissue function) should be assessed for clinical obesity. The diagnosis of clinical obesity requires one or both of the following main criteria: evidence of reduced organ or tissue function due to obesity (ie, signs, symptoms, or diagnostic tests showing abnormalities in the function of one or more tissue or organ system); or substantial, age-adjusted limitations of daily activities reflecting the specific effect of obesity on mobility, other basic activities of daily living (eg, bathing, dressing, toileting, continence, and eating), or both. People with clinical obesity should receive timely, evidence-based treatment, with the aim to induce improvement (or remission, when possible) of clinical manifestations of obesity and prevent progression to end-organ damage. People with preclinical obesity should undergo evidence-based health counselling, monitoring of their health status over time, and, when applicable, appropriate intervention to reduce risk of developing clinical obesity and other obesity-related diseases, as appropriate for the level of individual health risk. Policy makers and health authorities should ensure adequate and equitable access to available evidence-based treatments for individuals with clinical obesity, as appropriate for people with a chronic and potentially life-threatening illness. Public health strategies to reduce the incidence and prevalence of obesity at population levels must be based on current scientific evidence, rather than unproven assumptions that blame individual responsibility for the development of obesity. Weight-based bias and stigma are major obstacles in efforts to effectively prevent and treat obesity; health-care professionals and policy makers should receive proper training to address this important issue of obesity. All recommendations presented in this Commission have been agreed with the highest level of consensus among the commissioners (grade of agreement 90–100%) and have been endorsed by 76 organisations worldwide, including scientific societies and patient advocacy groups.

Evaluation of Energy Balance Estimated From Total Energy Expenditure and Body Composition Changes in Junior Sumo Wrestlers: An Observational Study Over Six Months

Background Sumo is a sport that requires wrestlers to develop their physique from childhood for athletic advantage. However, the energy expenditure and energy balance required for the growth of junior Sumo wrestlers remain unclear. This study aimed to determine the energy balance of junior Sumo wrestlers over six months using doubly labeled water (DLW) and bioelectrical impedance analysis (BIA). Methodology A total of 12 male Sumo wrestlers were affiliated with a local Sumo club (average age = 15 ± 1 years). The total energy expenditure (TEE) was measured using DLW, whereas body composition was evaluated using BIA. Daily physical activity was quantified using a tri-accelerometer (Active style Pro HJA-750C). Results The TEE was 4,194 ± 734 kcal/day, while daily physical activity without training was 786 ± 50 minutes. Within six months, the body weight increased by 2.0 ± 3.2 kg, fat-free mass (FFM) was augmented by 2.1 kg, while fat mass did not change significantly. The surplus energy accumulated was 5.6 ± 213 kcal/day. Conclusions The excess energy of junior Sumo wrestlers predominantly increases their FFM. To increase their physical prowess, wrestlers adhere to a lifestyle characterized by high-intensity training and attenuated daily physical activity.

Total daily energy expenditure and elevated water turnover in a small-scale semi-nomadic pastoralist society from Northern Kenya

BACKGROUND

Pastoralists live in challenging environments, which may be accompanied by unique activity, energy, and water requirements.

AIM

Few studies have examined whether the demands of pastoralism contribute to differences in total energy expenditure (TEE) and water turnover (WT) compared to other lifestyles.

SUBJECTS AND METHODS

Accelerometer-derived physical activity, doubly labelled water-derived TEE and WT, and anthropometric data were collected for 34 semi-nomadic Daasanach adults from three northern Kenyan communities with different levels of pastoralist activity. Daasanach TEEs and WTs were compared to those of other small-scale and industrialised populations.

RESULTS

When modelled as a function of fat-free-mass, fat-mass, age, and sex, TEE did not differ between Daasanach communities. Daasanach TEE (1564-4172 kcal/day) was not significantly correlated with activity and 91% of TEEs were within the range expected for individuals from comparison populations. Mean WT did not differ between Daasanach communities; Daasanach absolute (7.54 litres/day men; 7.46 litres/day women), mass-adjusted, and TEE-adjusted WT was higher than most populations worldwide.

CONCLUSIONS

The similar mass-adjusted TEE of Daasanach and industrialised populations supports the hypothesis that habitual TEE is constrained, with physically demanding lifestyles necessitating trade-offs in energy allocation. Elevated WT in the absence of elevated TEE likely reflects a demanding active lifestyle in a hot, arid climate.

Obesity-induced and weight-loss-induced physiological factors affecting weight regain

Weight regain after successful weight loss resulting from lifestyle interventions is a major challenge in the management of overweight and obesity. Knowledge of the causal mechanisms for weight regain can help researchers and clinicians to find effective strategies to tackle weight regain and reduce obesity-associated metabolic and cardiovascular complications. This Review summarizes the current understanding of a number of potential physiological mechanisms underlying weight regain after weight loss, including: the role of adipose tissue immune cells; hormonal and neuronal factors affecting hunger, satiety and reward; resting energy expenditure and adaptive thermogenesis; and lipid metabolism (lipolysis and lipid oxidation). We describe and discuss obesity-associated changes in these mechanisms, their persistence during weight loss and weight regain and their association with weight regain. Interventions to prevent or limit weight regain based on these factors, such as diet, exercise, pharmacotherapy and biomedical strategies, and current knowledge on the effectiveness of these interventions are also reviewed.

How can physical activity facilitate a sustainable future? Reducing obesity and chronic disease

This review examines the ways in which physical activity can contribute to a sustainable future by addressing significant public health issues. The review begins by identifying obesity and ageing as two major challenges facing societies around the world due to the association of both with the risk of chronic disease. Recent developments in the understanding and treatment of obesity are examined followed by an appraisal of the role of exercise alone and in combination with other therapies in preventing and managing obesity. The review then addresses the interaction between exercise and appetite due to the central role appetite plays in the development of overweight and obesity. The final section of the review examines the potential of physical activity to combat age-related chronic disease risk including CVD, cancer and dementia. It is concluded that while bariatric surgery and pharmacotherapy are the most effective treatments for severe obesity, physical activity has a role to play facilitating and enhancing weight loss in combination with other methods. Where weight/fat reduction via exercise is less than expected this is likely due to metabolic adaptation induced by physiological changes facilitating increased energy intake and decreased energy expenditure. Physical activity has many health benefits independent of weight control including reducing the risk of developing CVD, cancer and dementia and enhancing cognitive function in older adults. Physical activity may also provide resilience for future generations by protecting against the more severe effects of global pandemics and reducing greenhouse gas emissions via active commuting.

Exploring the Therapeutic Potential of Targeting GH and IGF-1 in the Management of Obesity: Insights from the Interplay between These Hormones and Metabolism

Obesity is a growing public health problem worldwide, and GH and IGF-1 have been studied as potential therapeutic targets for managing this condition. This review article aims to provide a comprehensive view of the interplay between GH and IGF-1 and metabolism within the context of obesity. We conducted a systematic review of the literature that was published from 1993 to 2023, using MEDLINE, Embase, and Cochrane databases. We included studies that investigated the effects of GH and IGF-1 on adipose tissue metabolism, energy balance, and weight regulation in humans and animals. Our review highlights the physiological functions of GH and IGF-1 in adipose tissue metabolism, including lipolysis and adipogenesis. We also discuss the potential mechanisms underlying the effects of these hormones on energy balance, such as their influence on insulin sensitivity and appetite regulation. Additionally, we summarize the current evidence regarding the efficacy and safety of GH and IGF-1 as therapeutic targets for managing obesity, including in pharmacological interventions and hormone replacement therapy. Finally, we address the challenges and limitations of targeting GH and IGF-1 in obesity management.

Total daily energy expenditure has declined over the past three decades due to declining basal expenditure, not reduced activity expenditure

Obesity is caused by a prolonged positive energy balance1,2. Whether reduced energy expenditure stemming from reduced activity levels contributes is debated3,4. Here we show that in both sexes, total energy expenditure (TEE) adjusted for body composition and age declined since the late 1980s, while adjusted activity energy expenditure increased over time. We use the International Atomic Energy Agency Doubly Labelled Water database on energy expenditure of adults in the United States and Europe (n = 4,799) to explore patterns in total (TEE: n = 4,799), basal (BEE: n = 1,432) and physical activity energy expenditure (n = 1,432) over time. In males, adjusted BEE decreased significantly, but in females this did not reach significance. A larger dataset of basal metabolic rate (equivalent to BEE) measurements of 9,912 adults across 163 studies spanning 100 years replicates the decline in BEE in both sexes. We conclude that increasing obesity in the United States/Europe has probably not been fuelled by reduced physical activity leading to lowered TEE. We identify here a decline in adjusted BEE as a previously unrecognized factor.

The fire of evolution: energy expenditure and ecology in primates and other endotherms

Total energy expenditure (TEE) represents the total energy allocated to growth, reproduction and body maintenance, as well as the energy expended on physical activity. Early experimental work in animal energetics focused on the costs of specific tasks (basal metabolic rate, locomotion, reproduction), while determination of TEE was limited to estimates from activity budgets or measurements of subjects confined to metabolic chambers. Advances in recent decades have enabled measures of TEE in free-living animals, challenging traditional additive approaches to understanding animal energy budgets. Variation in lifestyle and activity level can impact individuals' TEE on short time scales, but interspecific differences in TEE are largely shaped by evolution. Here, we review work on energy expenditure across the animal kingdom, with a particular focus on endotherms, and examine recent advances in primate energetics. Relative to other placental mammals, primates have low TEE, which may drive their slow pace of life and be an evolved response to the challenges presented by their ecologies and environments. TEE variation among hominoid primates appears to reflect adaptive shifts in energy throughput and allocation in response to ecological pressures. As the taxonomic breadth and depth of TEE data expand, we will be able to test additional hypotheses about how energy budgets are shaped by environmental pressures and explore the more proximal mechanisms that drive intra-specific variation in energy expenditure.

Sex inequality driven by dispersal

Inequality between the sexes is pervasive both outside and inside the home. One contributing factor could be the dispersal of one sex at marriage that sets up sex-specific differences in relatedness to the group. Here we exploit the ecological diversity and different social structures found in southwest China to investigate the role of sex-biased dispersal on inequality in the sexual division of labor. We use a wearable fitness tracker and validated readings by confirming that participants' daily "steps" were positively correlated with time spent in high-energy activities, such as agriculture and animal husbandry work, and negatively correlated with low-energy activities, such as leisure and relaxation. We applied multilevel comparative approaches to examine the relative workload pattern between the sexes under different dispersal states. Our results reveal two characteristics that lead to an unfavorable division of workload: being female and dispersing at marriage. This is consistent with the hypothesis that males have increased bargaining power when remaining in their natal home, leading to inequality in workload.