Obesity Reviews

doi: 10.1111/obr.12810pmid: N/A

No abstract is available for this article.

Dulloo, A. G.; Miles‐Chan, J.; Schutz, Y.; Montani, J.‐P.

doi: 10.1111/obr.12786pmid: 30511502

Increasing lifestyle energy expenditure has long been advocated in the prevention and treatment of obesity, as embodied in the ancient prescription of Hippocrates (the ‘father of modern medicine’) that people with obesity should eat less and exercise more. However, the long‐term outcome of exercise alone or in combination with dieting in obesity management is poor. To understand the reasons underlying these failures and to develop novel strategies that target lifestyle energy expenditure in both prevention and treatment of obesity, research over the past decades has focused on (i) the interactions between physical activity and body weight (and its composition) throughout the lifespan; (ii) the influence of biology and potential compensatory changes in energy expenditure, food intake and food assimilation in response to energy deficits; and (iii) the impact of the built environment (outdoor and indoor) and smart technology on physical activity behaviours, thermoregulatory thermogenesis and metabolic health. It is against this background that recent advances relevant to the theme of ‘Targeting Lifestyle Energy Expenditure in the Management of Obesity and Health: From Biology to Built Environment’ are addressed in this overview and the nine review articles in this supplement, reporting the proceedings of the 9th Fribourg Obesity Research Conference.

Westerterp, K. R.

doi: 10.1111/obr.12781pmid: 30511504

Physical activity and body composition show a typical pattern over the lifecycle. Fat‐free mass and physical performance generally peak in early adulthood. Here, evidence for a relation between physical activity changes over the life span and the development of sarcopenic obesity is presented. Activity‐induced energy expenditure increases with body size and physical activity during growth. The physical activity level, calculated by expressing total energy expenditure as a multiple of resting energy expenditure, gradually increases from early age to adulthood to decrease again in old age. Habitual physical activity has a significant effect on growth of fat‐free mass during adolescence and thus on peak fat‐free mass and physical performance in early adulthood. Older subjects have a lower fat‐free mass and lower physical activity levels but there is no association, suggesting physical activity does not protect against loss of lean body mass at higher age. Prevention of sarcopenic obesity starts with a physically active lifestyle to develop a healthy peak fat‐free mass and subsequent prevention of excess fat gain. The change from a physically active to a more sedentary routine in later life requires restriction of energy intake to maintain energy balance.

Byrne, N. M.; Hills, A. P.

doi: 10.1111/obr.12788pmid: 30511509

Despite longstanding recognition of the benefits of a physically active lifestyle, there remains ambiguity regarding exactly how much exercise should be promoted to raise total energy expenditure (TEE) and improve health. This review provides a brief summary of the dose–response relationship between physical activity and relative risk of morbidity and mortality; mechanisms through which exercise drives an increase in TEE; the highest reported levels of TEE measured via doubly labelled water; and the potential impact of non‐compliance and confounders in moderating the contribution of exercise to increase TEE. Cohort studies provide a compelling argument that ‘more is better’ regarding the exercise dose for increasing TEE, that increasing TEE is protective for health, and that this is mediated through increased cardiorespiratory fitness. However, growing evidence shows that ever increasing volumes of weekly physical activity may reverse the cost–benefit seen with more modest doses. Animal and human studies show that the elevation in TEE associated with increasing exercise volume is commonly less than expected, due to physiological confounders. Further, there is considerable evidence of behavioural non‐compliance to planned exercise in all but the most highly motivated athletes. Therefore, inbuilt defence mechanisms may safeguard against TEE being elevated to maximum levels.

Pontzer, H.; Wood, B. M.; Raichlen, D. A.

doi: 10.1111/obr.12785pmid: 30511505

Hunter‐gatherer populations are remarkable for their excellent metabolic and cardiovascular health and thus are often used as models in public health, in an effort to understand the root, evolutionary causes of non‐communicable diseases. Here, we review recent work on health, activity, energetics and diet among hunter‐gatherers and other small‐scale societies (e.g. subsistence farmers, horticulturalists and pastoralists), as well as recent fossil and archaeological discoveries, to provide a more comprehensive perspective on lifestyle and health in these populations. We supplement these analyses with new data from the Hadza, a hunter‐gatherer population in northern Tanzania. Longevity among small‐scale populations approaches that of industrialized populations, and metabolic and cardiovascular disease are rare. Obesity prevalence is very low (<5%), and mean body fat percentage is modest (women: 24–28%, men: 9–18%). Activity levels are high, exceeding 100 min d−1 of moderate and vigorous physical activity, but daily energy expenditures are similar to industrialized populations. Diets in hunter‐gatherer and other small‐scale societies tend to be less energy dense and richer in fibre and micronutrients than modern diets but are not invariably low carbohydrate as sometimes argued. A more integrative understanding of hunter‐gatherer health and lifestyle, including elements beyond diet and activity, will improve public health efforts in industrialized populations.

Doucet, É.; McInis, K.; Mahmoodianfard, S.

doi: 10.1111/obr.12783pmid: 30511511

Obesity is an extremely resilient condition. Weight loss is most challenging, and weight recidivism is rampant. There is accumulating evidence highlighting that energy deficits meant to produce increased mobilization of energy stores trigger a number of somewhat persistent adaptations that together increase the drive to eat and decrease energy output. These adaptations ostensibly enable a context where the likelihood of energy compensation is heightened. In fact, energy compensation is present for both diet and exercise induced energy deficits although at different magnitudes. For the most part, the energy compensation in response to exercise induced energy deficits seems to be larger. Interestingly, energy compensation appears to be greater for longer interventions, an effect independent of whether the energy deficit is induced through diet or exercise. The latter suggests that the increased drive to eat and the reduced energy expenditure that accompany weight loss might be successfully fought off initially. However, with time there seems to be increasing erosion of the behaviours that initially opposed adaptations to weight loss and increased energy compensation progressively sets in. Under such conditions, it would seem prudent to propose weight loss targets that align with a level of behaviour modifications that can be sustained indefinitely.

Sainsbury, A.; Wood, R. E.; Seimon, R. V.; Hills, A. P.; King, N. A.; Gibson, A. A.; Byrne, N. M.

doi: 10.1111/obr.12787pmid: 30511512

Eating patterns involving intermittent energy restriction (IER) include ‘intermittent fasting’ where energy intake is severely restricted for several ‘fasting’ days per week, with ‘refeeding’ days (involving greater energy intake than during fasting days) at other times. Intermittent fasting does not improve weight loss compared to continuous energy restriction (CER), where energy intake is restricted every day. We hypothesize that weight loss from IER could be improved if refeeding phases involved restoration of energy balance (i.e. not ongoing energy restriction, as during intermittent fasting). There is some evidence in adults with overweight or obesity showing that maintenance of a lower weight may attenuate (completely or partially) some of the adaptive responses to energy restriction that oppose ongoing weight loss. Other studies show some adaptive responses persist unabated for years after weight loss. Only five randomized controlled trials in adults with overweight or obesity have compared CER with IER interventions that achieved energy balance (or absence of energy restriction) during refeeding phases. Two reported greater weight loss than CER, whereas three reported similar weight loss between interventions. While inconclusive, it is possible that achieving energy balance (i.e. avoiding energy restriction or energy excess) during refeeding phases may be important in realizing the potential of IER.

Nilaweera, K. N.; Speakman, J. R.

doi: 10.1111/obr.12780pmid: 30511508

The growth of the intestine requires energy, which is known to be met by catabolism of ingested nutrients. Paradoxically, during whole body energy deficit including calorie restriction, the intestine grows in size. To understand how and why this happens, we reviewed data from several animal models of energetic challenge. These were bariatric surgery, cold exposure, lactation, dietary whey protein intake and calorie restriction. Notably, these challenges all reduced the adipose tissue mass, altered hypothalamic neuropeptide expression and increased intestinal size. Based on these data, we propose that the loss of energy in the adipose tissue promotes the growth of the intestine via a signalling mechanism involving the hypothalamus. We discuss possible candidates in this pathway including data showing a correlative change in intestinal (ileal) expression of the cyclin D1 gene with adipose tissue mass, adipose derived‐hormone leptin and hypothalamic expression of leptin receptor and the pro‐opiomelanocortin gene. The ability of the intestine to grow in size during depletion of energy stores provides a mechanism to maximize assimilation of ingested energy and in turn sustain critical functions of tissues important for survival.

Isacco, L.; Miles‐Chan, J. L.

doi: 10.1111/obr.12779pmid: 30511503

With current ‘one‐size‐fits‐all’ obesity prevention and management strategies proving largely ineffective, the focus has shifted towards a more tailored, individualized approach. However, investigation of the mechanisms underlying inter‐individual variability in metabolic profile and response to intervention often yield conflicting results. Indeed, it is perhaps surprising that despite at least a century of recognition that sex hormones influence metabolism, firm conclusions regarding the effects of the menstrual cycle, hormonal contraception and menopause on many aspects of energy expenditure and substrate utilization remain to be drawn. In this review, we examine current evidence relating to gender‐specific considerations in the promotion of physical activity, thermogenesis and fat oxidation for body‐weight regulation, including the relationship between sex hormone status and non‐exercise activity thermogenesis – an energy expenditure compartment that is often overlooked in favour of traditional exercise/sport physical activities yet presents a viable target in the search for effective weight management.

Ulijaszek, S.

doi: 10.1111/obr.12790pmid: 30511510

Physical activity in the built environment of high income countries may be changing faster than at any time prior to the 2000s, with the engagement of social media, smart devices and increasing urban smartness that has come with the Internet of Things. This article describes the most salient features of built environments that have facilitated physical activity between the 1980s and 2000s (most importantly walkability and active transport with bicycles). It goes on to use the anthropological three bodies framework in association with that of forms of capital, to explore how the use of smart devices and increasing incorporation of smartness and performativity into architecture and urban planning since the 2000s might influence physical activity. Smartness and use of smart devices in the built environment should favour increased physical activity through new types of sociality that they facilitate. In turn, engagement with such technologies offers an important opportunity for the empowerment of the individual body–self and the social body towards increased physical activity.