Obesity Reviews

There is utility in understanding the antecedents of binge eating (BE), with a view to explaining poorer weight loss treatment responses in this subgroup. A systematic review was completed according to Preferred Reporting Items for Systematic Reviews and Meta‐Analyses (PRISMA) guidelines with the aim of exploring associations between emotions and eating behaviour in a population affected by obesity and binge eating disorder (BED). A comprehensive literature search of four electronic databases (2004–2014) yielded 15 studies for inclusion. Included studies performed poorly on data quality analysis with respect to controlling for confounding variables, and sample size. Included papers largely focused on negative emotions as antecedents of BE; depression was consistently associated with a BED‐obese classification and BE. Negative mood, sadness, tension and instability of emotions were found to be antecedents of BE in an adult BED‐obese sample. However, findings were mixed regarding the role of stress, anger and positive emotions within the BED‐obese population. Recommendations are presented for the identification of BED, and ecologically valid experimental designs that further understanding of the complex and varied emotions that associate with BE. The implications of these and other limitations for both researchers and practitioners are discussed. The paper concludes with recommendations for future research alongside suggestions for practitioners. © 2015 World Obesity

Rigorous estimates of preference‐based utilities are important inputs into economic evaluations of childhood obesity interventions, yet no published review currently exists examining utility by weight status in paediatric populations. A comprehensive systematic literature review and meta‐analysis was therefore undertaken, pooling data on preference‐based health state utilities by weight status in children using a random‐effects model. Tests for heterogeneity were performed, and publication bias was assessed. Of 3,434 potentially relevant studies identified, 11 met our eligibility criteria. Estimates of Cohen'sdstatistic suggested a small effect of weight status on preference‐based utilities. Mean utility values were estimated as 0.85 (95% uncertainty interval [UI] 0.84–0.87), 0.83 (95% UI 0.81–0.85), 0.82 (95% UI 0.79–0.84) and 0.83 (95% UI 0.80–0.86) for healthy weight, overweight, obese and overweight/obese states, respectively. Meta‐analysis of studies reporting utility values for both healthy weight and overweight/obese participants found a statistically significant weighted mean difference (0.015, 95% UI 0.003–0.026). A small but statistically significant difference was also estimated between healthy weight and overweight participants (0.011, 95% UI 0.004–0.018). Study findings suggest that paediatric‐specific benefits of obesity interventions may not be well reflected by available utility measures, potentially underestimating cost‐effectiveness if weight loss in childhood/adolescence improves health or well‐being.

The objective of this study was to evaluate the evidence on whether childhood obesity is a risk factor for adult disease, independent of adult body mass index (BMI). Ovid MEDLINE (1948–May 2011), EMBASE (1980–2011 week 18) and the Cochrane Library (1990–2011) were searched for published studies of BMI from directly measured weight and height in childhood (2–19 years) and disease outcomes in adulthood. Data were synthesized in a narrative fashion. Thirty‐nine studies (n 181–1.1 million) were included in the review. There was evidence for associations between childhood BMI and type 2 diabetes, hypertension and coronary heart disease. Few studies examined associations independent of adult BMI; these showed that effect sizes were attenuated after adjustment for adult BMI in standard regression analyses. Although there is a consistent body of evidence for associations between childhood BMI and cardiovascular outcomes, there is a lack of evidence for effects independent of adult BMI. Studies have attempted to examine independent effects using standard adjustment for adult BMI, which is subject to over‐adjustment and problems with interpretation. Studies that use more robust designs and analytical techniques are needed to establish whether childhood obesity is an independent risk factor for adult disease.

Bariatric surgery is the most effective treatment for morbid obesity; however, a subset of patients who undergo this procedure regain weight or achieve suboptimal weight loss results. A large number of studies have examined whether psychological variables play a role in weight loss surgery outcome. Although presurgical psychopathology has been found to be associated with suboptimal results in some studies, this literature is equivocal. These inconsistent findings are reviewed and considered in the context of contemporary models of psychopathology. More specifically, the review focuses on the limitations of atheoretical, descriptive diagnostic systems and examines whether comorbidity within the mood/anxiety disorders, impulse control/substance use disorders and thought disorders can account for the inconsistent findings reported to date. Contemporary models of psychopathology are highlighted and linked to the Research Domain Criteria, which have been advanced by the National Institute of Health. Means for assessing psychological constructs congruent with these models are reviewed. Recommendations are made for standardizing approaches to investigating how psychopathology contributes to suboptimal bariatric surgery outcomes.

Obesity prevalence is generally higher in women than in men, and there is also a sex difference in body fat distribution. Sex differences in obesity can be explained in part by the influence of gonadal steroids on body composition and appetite; however, behavioural, socio‐cultural and chromosomal factors may also play a role. This review, which evolved from the 2008 Stock Conference on sex differences in obesity, summarizes current research and recommendations related to hormonal and neuroendocrine influences on energy balance and fat distribution. A number of important gaps in the research are identified, including a need for more studies on chromosomal sex effects on energy balance, the role of socio‐cultural (i.e. gender) factors in obesity and the potential deleterious effects of high‐fat diets during pregnancy on the foetus. Furthermore, there is a paucity of clinical trials examining sex‐specific approaches and outcomes of obesity treatment (lifestyle‐based or pharmacological), and research is urgently needed to determine whether current weight loss programmes, largely developed and tested on women, are appropriate for men. Last, it is important that both animal and clinical research on obesity be designed and analysed in such a way that data can be separately examined in both men and women.

The objective of this article was to estimate the risk of discontinuation due to adverse events in trials of orlistat, sibutramine and rimonabant. Medline, EMBASE, the Cochrane controlled trials register and reference lists of identified articles were searched from 1990 to May 2008. All randomized placebo‐controlled trials of 12–24 months of duration on adults using licensed doses were included. Studies/study arms were excluded if they evaluated weight maintenance after weight loss. Trials were identified, subjected to inclusion and exclusion criteria and reviewed. Data on participants, interventions and discontinuation were extracted and trials rated for quality based on established criteria. A random effects model was used to estimate pooled risk ratios, risk differences and number needed to harm (NNH). A total of 28 trials met the inclusion criteria (16 orlistat, 7 sibutramine and 5 rimonabant). The risk ratios for discontinuation due to adverse events were significantly elevated for rimonabant (2.00; 1.66–2.41) and orlistat (1.59; 1.21–2.08), but not sibutramine (0.98, 0.68–1.41). Compared with placebo, the risk difference was the largest for rimonabant (7%, 5–9%; NNH 14, 11–19), followed by orlistat (3%, 1–4%; NNH 39, 25–83), while no significant difference was seen for sibutramine (0.2%, −3 to 4%; NNH 500). The most common adverse events leading to withdrawal were gastrointestinal for orlistat (40%) and psychiatric for rimonabant (47%). Corresponding information was unavailable for sibutramine. In conclusion, available weight loss drugs differ markedly regarding risk of discontinuation due to adverse events, as well as in underlying causes of these events. Given the large number of patients eligible for treatment, the low NNH for rimonabant is a concern.

Obesity prevalence, particularly in children and young adults, is perilously increasing worldwide foreseeing serious negative health impacts in the future to come. Obesity is linked to impaired male gonadal function and is currently a major cause of hypogonadism. Besides signs and symptoms directly derived from decreased circulating testosterone levels, males with obesity also present poor fertility outcomes, further evidencing the parallelism between obesity and male reproductive function. In addition, males with androgen deficiency also exhibit increased fat accumulation and reduced muscle and mineral bone mass. Thus, compelling evidence highlights a vicious cycle where male hypogonadism can lead to increased adiposity, while obesity can be a cause for male hypogonadism. On the opposite direction, sustained weight loss can attain amelioration of male gonadal function. In this scenario, a thorough evaluation of gonadal function in men with obesity is crucial to dissect the causes from the consequences in order to target clinical interventions towards maximized improvement of reproductive health. This review will address the causes and consequences of the bidirectional relationship between obesity and hypogonadism, highlighting the implicit male reproductive repercussions.

Taxes and subsidies are increasingly being considered as potential policy instruments to incentivize consumers to improve their food and beverage consumption patterns and related health outcomes. This study provided a systematic review of recent U.S. studies on the price elasticity of demand for sugar‐sweetened beverages (SSBs), fast food, and fruits and vegetables, as well as the direct associations of prices/taxes with body weight outcomes. Based on the recent literature, the price elasticity of demand for SSBs, fast food, fruits and vegetables was estimated to be −1.21, −0.52, −0.49 and −0.48, respectively. The studies that linked soda taxes to weight outcomes showed minimal impacts on weight; however, they were based on existing state‐level sales taxes that were relatively low. Higher fast‐food prices were associated with lower weight outcomes particularly among adolescents, suggesting that raising prices would potentially impact weight outcomes. Lower fruit and vegetable prices were generally found to be associated with lower body weight outcomes among both low‐income children and adults, suggesting that subsidies that would reduce the cost of fruits and vegetables for lower‐socioeconomic populations may be effective in reducing obesity. Pricing instruments should continue to be considered and evaluated as potential policy instruments to address public health risks.

Short sleep duration has been associated with obesity in numerous epidemiological studies. However, such association studies cannot establish evidence of causality. Clinical intervention studies, on the other hand, can provide information on a causal effect of sleep duration on markers of weight gain: energy intake and energy expenditure. Herein is an overview of the science related to the impact of sleep restriction, in the context of clinical intervention studies, on energy intake, energy expenditure and body weight. Additionally, studies that evaluate the impact of sleep restriction on weight loss and the impact of sleep extension on appetite are discussed. Information to date suggests that weight management is hindered when attempted in the context of sleep restriction, and the public should be made aware of the negative consequences of sleep restriction for weight regulation.

Previous reviews of childhood obesity prevention have focused largely on schools and findings have been inconsistent. Funded by the US Agency for Healthcare Research and Quality (AHRQ) and the National Institutes of Health, we systematically evaluated the effectiveness of childhood obesity prevention programmes conducted in high‐income countries and implemented in various settings. We searched MEDLINE®, Embase, PsycINFO, CINAHL®, ClinicalTrials.gov and the Cochrane Library from inception through 22 April 2013 for relevant studies, including randomized controlled trials, quasi‐experimental studies and natural experiments, targeting diet, physical activity or both, and conducted in children aged 2–18 in high‐income countries. Two reviewers independently abstracted the data. The strength of evidence (SOE) supporting interventions was graded for each study setting (e.g. home, school). Meta‐analyses were performed on studies judged sufficiently similar and appropriate to pool using random effect models. This paper reported our findings on various adiposity‐related outcomes. We identified 147 articles (139 intervention studies) of which 115 studies were primarily school based, although other settings could have been involved. Most were conducted in the United States and within the past decade. SOE was high for physical activity‐only interventions delivered in schools with home involvement or combined diet–physical activity interventions delivered in schools with both home and community components. SOE was moderate for school‐based interventions targeting either diet or physical activity, combined interventions delivered in schools with home or community components or combined interventions delivered in the community with a school component. SOE was low for combined interventions in childcare or home settings. Evidence was insufficient for other interventions. In conclusion, at least moderately strong evidence supports the effectiveness of school‐based interventions for preventing childhood obesity. More research is needed to evaluate programmes in other settings or of other design types, especially environmental, policy and consumer health informatics‐oriented interventions.