Association of run‐in periods with weight loss in obesity randomized controlled trials

Study‐level design characteristics that inform the optimal design of obesity randomized controlled trials (RCTs) have been examined in few studies. A pre‐randomization run‐in period is one such design element that may influence weight loss. We examined 311 obesity RCTs published between 1 January 2007 and 1 July 2009 that examine d weight loss or weight gain prevention as a primary or secondary end‐point. Variables included run‐in period, pre‐post intervention weight loss, study duration (time), intervention type, percent female and degree of obesity. Linear regression was used to estimate weight loss as a function of (i) run‐in (yes/no) and (ii) run‐in, time, percent female, body mass index and intervention type. Interaction terms were also examined. Approximately 19% (18.6%) of the studies included a run‐in period, with pharmaceutical studies having the highest frequency. Although all intervention types were associated with weight loss (Mean = 2.80 kg, SD = 3.52), the inclusion of a pre‐randomization run‐in was associated with less weight loss (P = 0.0017) compared with studies that did not include a run‐in period. However, this association was not consistent across intervention types. Our results imply that in trials primarily targeting weight loss in adults, run‐in periods may not be beneficial for improving weight loss outcomes in interventions.     

Strategies to reduce attrition in weight loss interventions: A systematic review and meta‐analysis

The primary objective of the study was to identify the effect of intervention strategies on attrition within a weight loss programme among adults aged 18 to 65 years. The secondary objective of the study was to assess the impact of such intervention strategies among female‐only weight loss programmes. The literature search was performed in Ovid (CINAHL Plus, MEDLINE, EMBASE, Cochrane [Cochrane Database of Reviews, Cochrane Central Register of Controlled Trials, and Cochrane Methodology Register], and PsycINFO). Studies must have identified weight loss as the main aim and compared the primary weight loss programme alone (control) with the primary weight loss programme coupled with an additional intervention strategy (intervention). Papers must have had a mean participant age between 18 and 65 years and available in English. Fifty‐seven trials met the inclusion criteria and were included in the meta‐analysis. Strategies that successfully reduced attrition included the incorporation of financial incentives (n = 8), a multicomponent approach (n = 13), and use of self‐monitoring technology (n = 4). The majority of studies were of low to moderate methodological quality because of insufficient reporting. A limited number of female‐only trials were found (n = 13). Implementation of financial incentives, multicomponent interventions, and self‐monitoring technology help reduce attrition among adult weight loss programmes. Further studies are required to identify the impact of intervention strategies on attrition in women.     

Methodological quality of behavioural weight loss studies: a systematic review

This systematic review assessed the methodological quality of behavioural weight loss intervention studies conducted among adults and associations between quality and statistically significant weight loss outcome, strength of intervention effectiveness and sample size. Searches for trials published between January, 2009 and December, 2014 were conducted using PUBMED, MEDLINE and PSYCINFO and identified ninety studies. Methodological quality indicators included study design, anthropometric measurement approach, sample size calculations, intent‐to‐treat (ITT) analysis, loss to follow‐up rate, missing data strategy, sampling strategy, report of treatment receipt and report of intervention fidelity (mean = 6.3). Indicators most commonly utilized included randomized design (100%), objectively measured anthropometrics (96.7%), ITT analysis (86.7%) and reporting treatment adherence (76.7%). Most studies (62.2%) had a follow‐up rate > 75% and reported a loss to follow‐up analytic strategy or minimal missing data (69.9%). Describing intervention fidelity (34.4%) and sampling from a known population (41.1%) were least common. Methodological quality was not associated with reporting a statistically significant result, effect size or sample size. This review found the published literature of behavioural weight loss trials to be of high quality for specific indicators, including study design and measurement. Identified for improvement include utilization of more rigorous statistical approaches to loss to follow up and better fidelity reporting.     

Effectiveness of male-only weight loss and weight loss maintenance interventions: a systematic review with meta-analysis

The objectives of this systematic review were to investigate the effectiveness of male-only weight loss and weight loss maintenance interventions and to identify intervention characteristics associated with effectiveness. In May 2011, a systematic literature search with no date restrictions was conducted across eight databases. Twenty-four articles describing 23 studies met the eligibility criteria. All studies included a weight loss intervention and four studies included an additional weight loss maintenance intervention. Study quality was mostly poor for weight loss studies (median = 3/10, range = 1-9) and weight loss maintenance studies (median = 3.5/10, range = 1-6). Twenty-three of 31 individual weight loss interventions (74%) from the eligible studies were considered effective. Meta-analysis revealed a significant difference in weight change favouring weight loss interventions over no-intervention controls at the last reported assessment (weighted mean difference -5.66 kg [-6.35, -4.97], Z = 16.04 [P < 0.00001]). Characteristics common to effectiveness were younger sample (mean age ≤ 42.8 years), increased frequency of contact (> 2.7 contacts/month), group face-to-face contact and inclusion of a prescribed energy restriction. Preliminary evidence suggests men-only weight loss programmes may effectively engage and assist men with weight loss. However, more high-quality studies are urgently needed to improve the evidence base, particularly for maintenance studies.     

Effectiveness of weight loss and maintenance interventions in women

Overweight and obesity in women contribute to increased risk of many health problems, including type 2 diabetes. A systematic review of the weight loss literature found 17 articles in which women were the sole subjects and studies were a minimum of 1 year or longer in duration. Data were pooled and average weight loss and maintenance for women at 6 and 12 months was determined for each of the six interventions. Diet as the primary intervention resulted in a weight loss of approximately 7 kg at 6 months (approximately 13% of their initial weight), which was maintained to 12 months. When specific goals for physical activity or weight loss medications were combined with diet, better outcomes were experienced. Regardless of the intervention, at approximately 6 months a weight loss plateau occurred. All of the studies included at least monthly follow-up.     

Effectiveness of weight loss interventions – is there a difference between men and women: a systematic review

Effective strategies are required to reduce the prevalence of overweight and obesity; however, the effectiveness of current weight loss programmes is variable. One contributing factor may be the difference in weight loss success between men and women. A systematic review was conducted to determine whether the effectiveness of weight loss interventions differs between men and women. Randomized controlled trials published up until March 2014 were included. Effect sizes (Hedges' g) were used to examine the difference in weight outcomes between men and women. A total of 58 studies met the eligibility criteria with 49 studies of higher quality included in the final data synthesis. Eleven studies that directly compared weight loss in men and women reported a significant sex difference. Ten of these reported that men lost more weight than women; however, women also lost a significant amount of weight. Analysis of effect sizes found small differences in weight loss favouring men for both diet (g = 0.489) and diet plus exercise (g = 0.240) interventions. There is little evidence from this review to indicate that men and women should adopt different weight loss strategies. Current evidence supports moderate energy restriction in combination with exercise for weight loss in both men and women.     

Systematic review of the use of financial incentives in treatments for obesity and overweight

Nine studies met the criteria for inclusion in this systematic review of randomized controlled trials of treatments for obesity and overweight involving the use of financial incentives, with reported follow-up of at least 1 year. All included trials were of behavioural obesity treatments. Justification of sample size and blinding procedure were not mentioned in any study. Attrition was well described in three studies and no study was analysed on an intention to treat basis. Participants were mostly women recruited through media advertisements. Mean age ranged from 35.7 to 52.8 years, and mean body mass index from 29.3 to 31.8 kg m⁻². Results from meta-analysis showed no significant effect of use of financial incentives on weight loss or maintenance at 12 months and 18 months. Further sub-analysis by mode of delivery and amount of incentives although also non-statistically significant were suggestive of very weak trends in favour of use of amounts greater than 1.2% personal disposable income, rewards for behaviour change rather than for weight, rewards based on group performance rather than for individual performance and rewards delivered by non-psychologists rather than delivered by psychologists.     

Factors that may impede the weight loss response to exercise-based interventions

The results of exercise programmes designed to reduce body fat are disappointing. However, the reporting of weight loss as mean values disguises those individuals who do lose significant amounts of fat. Why some participants produce significant exercise-induced fat loss whereas others lose little or increase fat stores is likely to be an outcome of a range of behavioural (e.g. sleep deprivation, caloric intake), inherited (e.g. muscle fibre type, gender) and physiological (e.g. hyperinsulinaemia, hypothyroidism) factors. The following review highlights possible factors involved in weight loss and discusses how individual differences may determine the extent of weight loss after an exercise intervention. Finally, implications for the treatment and prevention of obesity are discussed.     

Effective strategies for weight loss in post‐partum women: a systematic review and meta‐analysis

Post‐partum weight loss is critical to preventing and managing obesity in women, but the results from lifestyle interventions are variable and the components associated with successful outcomes are not yet clearly identified. This study aimed to identify lifestyle intervention strategies associated with weight loss in post‐partum women. MEDLINE, EMBASE, PubMed, CINAHL and four other databases were searched for lifestyle intervention studies (diet or exercise or both) in post‐partum women (within 12 months of delivery) published up to July 2014. The primary outcome was weight loss. Subgroup analyses were conducted for self‐monitoring, individual or group setting, intervention duration, intervention types, the use of technology as a support, and home‐ or centre‐based interventions. From 12,673 studies, 46 studies were included in systematic review and 32 randomized controlled trials were eligible for meta‐analysis (1,892 women, age 24–36 years). Studies with self‐monitoring had significantly greater weight lost than those without (?4.61 kg [?7.08, ?2.15] vs. ?1.34 kg [?1.66, ?1.02], P = 0.01 for subgroup differences). Diet and physical activity when combined were significantly more effective on weight loss compared with physical activity alone (?3.24 kg [?4.59, ?1.90] vs. ?1.63 kg [?2.16, ?1.10], P < 0.001 for subgroup differences). Lifestyle interventions that use self‐monitoring and take a combined diet‐and‐exercise approach have significantly greater weight loss in post‐partum women.     

Clinical effectiveness of very‐low‐energy diets in the management of weight loss: a systematic review and meta‐analysis of randomized controlled trials

Guidelines suggest that very‐low‐energy diets (VLEDs) should be used to treat obesity only when rapid weight loss is clinically indicated because of concerns about rapid weight regain. Literature databases were searched from inception to November 2014. Randomized trials were included where the intervention included a VLED and the comparator was no intervention or an intervention that could be given in a general medical setting in adults that were overweight. Two reviewers characterized the population, intervention, control groups, outcomes and appraised quality. The primary outcome was weight change at 12 months from baseline. Compared with a behavioural programme alone, VLEDs combined with a behavioural programme achieved ?3.9 kg [95% confidence interval (CI) ?6.7 to ?1.1] at 1 year. The difference at 24 months was ?1.4 kg (95%CI ?2.6 to ?0.2) and at 38–60 months was ?1.3 kg (95%CI ?2.9 to 0.2). Nineteen per cent of the VLED group discontinued treatment prematurely compared with 20% of the comparator groups, relative risk 0.96 (0.56 to 1.66). One serious adverse event, hospitalization with cholecystitis, was reported in the VLED group and none in the comparator group. Very‐low‐energy diets with behavioural programmes achieve greater long‐term weight loss than behavioural programmes alone, appear tolerable and lead to few adverse events suggesting they could be more widely used than current guidelines suggest.     

Post‐operative behavioural management in bariatric surgery: a systematic review and meta‐analysis of randomized controlled trials

Recent research has provided evidence that bariatric surgery maximizes long‐term weight loss in patients with severe obesity. However, a substantial number of patients experience poor weight loss outcome and weight regain over time. Post‐operative behavioural management may facilitate long‐term weight control in bariatric surgery population. The objective of this systematic review and meta‐analysis was to determine the effects of post‐operative behavioural management on weight loss following bariatric surgery. Eligible articles were systematically searched in electronic databases. Among the 414 citations, five randomized controlled trials, two prospective and eight retrospective cohort trials analysing behavioural lifestyle interventions and support groups fulfilled the inclusion criteria. The main finding is that behavioural management had a positive effect on weight loss following surgery. In 13 studies, patients receiving behavioural management had greater weight loss than patients receiving usual care or no treatment. A meta‐analysis of five randomized controlled trials suggests greater weight loss in patients with behavioural lifestyle interventions compared with control groups. Post‐operative behavioural management has the potential to facilitate optimal weight loss following bariatric surgery, but conclusions were limited by the small and heterogeneous samples of studies. A more rigorous empirical evaluation on its clinical significance is warranted to improve effectiveness of bariatric surgery.     

Treatment of Obesity in Primary Care Practice in the United States: A Systematic Review

OBJECTIVES  This review examines the results of randomized controlled trials in which behavioral weight loss interventions, used alone or with pharmacotherapy, were provided in primary care settings. DATA SOURCES  Literature search of MEDLINE, PubMed, Cochrane Systematic Reviews, CINAHL, and EMBASE (1950-present). Inclusion criteria for studies were: (1) randomized trial, (2) obesity intervention in US adults, and (3) conducted in primary care or explicitly intended to model a primary care setting. REVIEW METHODS  Both authors reviewed each study to extract treatment modality, provider, setting, weight change, and attrition. The CONSORT criteria were used to assess study quality. Due to the small number and heterogeneity of studies, results were summarized but not pooled quantitatively. RESULTS  Ten trials met the inclusion criteria. Studies were classified as: (1) PCP counseling alone, (2) PCP counseling + pharmacotherapy, and (3) “collaborative” obesity care (treatment delivered by a non-physician provider). Weight losses in the active treatment arms of these categories of studies ranged from 0.1 to 2.3 kg, 1.7 to 7.5 kg, and 0.4 to 7.7 kg, respectively. Most studies provided low- or moderate-intensity counseling, as defined by the US Preventive Services Task Force. CONCLUSIONS  Current evidence does not support the use of low- to moderate-intensity physician counseling for obesity, by itself, to achieve clinically meaningful weight loss. PCP counseling plus pharmacotherapy, or intensive counseling (from a dietitian or nurse) plus meal replacements may help patients achieve this goal. Further research is needed on different models of managing obesity in primary care practice.     

Sex differences in obesity and the regulation of energy homeostasis

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.     

Technology Interventions to Curb Obesity: A Systematic Review of the Current Literature

Obesity is a public health crisis that has reached epidemic proportions. Although intensive behavioral interventions can produce clinically significant weight loss, their cost to implement, coupled with resource limitations, pose significant barriers to scalability. To overcome these challenges, researchers have made attempts to shift intervention content to the Internet and other mobile devices. This article systematically reviews the recent literature examining technology-supported interventions for weight loss and maintenance among overweight and obese adults. Thirteen studies were identified that satisfied our inclusion criteria (12 weight loss trials, 1 weight maintenance trial). Our findings suggest that technology interventions may be efficacious at producing weight loss. However, several studies are limited by methodologic shortcomings. There are insufficient data to evaluate their efficacy for weight maintenance. Further research is needed that employs state-of-the-art methodology, with careful attention being paid to adherence and fidelity to intervention protocols.     

Cognitive training on eating behaviour and weight loss: A meta‐analysis and systematic review

Cognitive deficits play a role in the development and maintenance of overeating and obesity, and cognitive training in obesity refers to a family of interventions aimed at reducing overeating and obesity by improving these cognitive deficits. In this review, we synthesize the current literature on these issues by conducting a meta‐analysis of studies investigating the effects of cognitive trainings on eating behaviour and presenting a systematic review of studies investigating the effects of cognitive trainings on weight loss. We examined 66 independent experiments that examined the effects of cognitive training aimed at reducing cognitive bias or improving executive control on eating behaviour and weight loss. Overall, inhibition training, attention bias modification training, and episodic future thinking training significantly influenced eating behaviour; however, approach/avoidance training did not significantly influence eating behaviour. Moderator analyses indicated that the effect of inhibition training on eating behaviour was moderated by training task and food novelty, the effect of approach/avoidance training was moderated by food type, and the effect of episodic future thinking training was moderated by type of episodic future thinking. Literature reviewed on cognitive training and weight loss provided preliminary support for the effects of food‐specific inhibition training on weight loss from pre‐intervention to post intervention. However, because most of the included studies focused on short‐term outcomes in normal‐weight samples, longer duration studies in clinical populations (eg, individuals with obesity) are needed to examine the generalizability of these results.     

Racial and ethnic minority enrollment in randomized clinical trials of behavioural weight loss utilizing technology: a systematic review

Many racial and ethnic minority groups (minorities) are disproportionately affected by overweight and obesity; however, minorities are often under‐represented in clinical trials of behavioural weight loss (BWL) treatment, potentially limiting the generalizability of these trials' conclusions. Interventions involving technology may be particularly well suited to overcoming the barriers to minority enrollment in BWL trials, such as demanding or unpredictable work schedules, caregiving responsibilities and travel burdens. Thus, this systematic review aimed to describe minority enrollment in trials utilizing technology in interventions, as well as to identify which form(s) of technology yield the highest minority enrollment. Results indicated relatively low enrollment of minorities. Trials integrating smartphone use exhibited significantly greater racial minority enrollment than trials that did not; trials with both smartphone and in‐person components exhibited the highest racial minority enrollment. This review is the first to explore how the inclusion of technology in BWL trials relates to minority enrollment and can help address the need to improve minority enrollment in weight loss research.     

A systematic review with meta‐analyses of text message‐delivered behaviour change interventions for weight loss and weight loss maintenance

Short Message Service (SMS)‐delivered behaviour change interventions are frequently used to support weight management. This systematic review examines the effectiveness of SMS‐delivered behaviour change interventions for weight management. Electronic databases were searched for randomised controlled trials (RCTs) comparing SMS‐delivered adult weight management interventions to control groups, published between 1990 and 2018. Weight change was examined using random effects meta‐analyses at intervention cessation and postintervention follow‐up. Subgroup analyses examined intervention duration, SMS frequency, theory use, SMS interactivity, and SMS tailoring. Fifteen studies met inclusion criteria (2705 participants). For weight loss interventions (n = 12, 1977 participants), the mean difference in weight change was ?2.28 kg (95% confidence interval [CI] ?3.17 to ?1.36 kg). No studies reported postintervention follow‐up. For weight loss maintenance interventions (n = 3, 728 participants), the mean difference in weight change was ?0.68 kg (95% CI, ?1.31 to ?0.05 kg), and postintervention follow‐up (n = 2, 498 participants) effects were ?0.57 kg (95% CI, ?1.67 to 0.53 kg). No subgroup differences were found. SMS‐delivered behaviour change interventions for weight loss led to significant small to moderate weight loss and weight loss maintenance compared with control groups. Evidence on long‐term effects is limited. SMS‐delivered behaviour change interventions are a potentially effective and scalable intervention option for obesity treatment.     

Behavioural weight management programmes for adults assessed by trials conducted in everyday contexts: systematic review and meta‐analysis

This systematic review and meta‐analysis of effectiveness trials comparing multicomponent behavioural weight management programmes with controls in overweight and obese adults set out to determine the effectiveness of these interventions implemented in routine practice. To be included, interventions must have been multicomponent, delivered by the therapists who would deliver the intervention in routine practice and in that same context, and must be widely available or feasible to implement with little additional infrastructure or staffing. Searches of electronic databases were conducted, and augmented by screening reference lists and contacting experts (November 2012). Data were extracted by two reviewers, with mean difference between intervention and control for 12‐month change in weight, blood pressure, lipids and glucose calculated using baseline observation carried forward. Data were also extracted on adverse events, quality of life and mood measures. Although there were many published efficacy trials, only eight effectiveness trials met the inclusion criteria. Pooled results from five study arms providing access to commercial weight management programmes detected significant weight loss at 12 months (mean difference ?2.22 kg, 95% confidence interval [CI] ?2.90 to ?1.54). Results from two arms of a study testing a commercial programme providing meal replacements also detected significant weight loss (mean difference ?6.83 kg, 95% CI ?8.39 to ?5.26). In contrast, pooled results from five interventions delivered by primary care teams showed no evidence of an effect on weight (mean difference ?0.45 kg, 95% CI ?1.34 to 0.43). One study testing an interactive web‐based intervention detected a significant effect in favour of the intervention at 12 months, but the study was judged to be at high risk of bias and the effect did not persist at 18 months. Few studies reported other outcomes, limiting comparisons between interventions. Few trials have examined the effectiveness of behavioural weight loss programmes delivered in everyday contexts. These trials suggest that commercial interventions delivered in the community are effective for achieving weight loss. There is no evidence that interventions delivered within primary care settings by generalist primary care teams trained in weight management achieve meaningful weight loss.     

The effect of non‐surgical weight loss interventions on urinary incontinence in overweight women: a systematic review and meta‐analysis

Although the aetiology of urinary incontinence can be multifactorial, in some cases weight loss could be considered as a part of the therapeutic approach for urinary incontinence in people who are overweight. The objective of this study was to review and meta‐analyse the effect of non‐surgical weight loss interventions on urinary incontinence in overweight women. Web of Science, PubMed, Pedro, SPORTDiscus and Cochrane were systematically searched for clinical trials that met the a priori set criteria. Data of women who participated in non‐surgical weight loss interventions (diet, exercise, medication or a combination) were included in the meta‐analysis. After removing duplicates, 62 articles remained for screening on title, abstract and full text. Six articles (totalling 2,352 subjects in the intervention groups) were included for meta‐analysis. The mean change in urinary incontinence (reported as frequency or quantity, depending on the study) after a non‐surgical weight loss intervention, expressed as standardized effect size and corrected for small sample sizes (Hedges' g), was ?0.30 (95%CI = ?0.47 to ?0.12). This systematic review and meta‐analysis shows evidence that a non‐surgical weight loss intervention has the potential to improve urinary incontinence and should be considered part of standard practice in the management of urinary incontinence in overweight women.     

Successful weight loss maintenance: A systematic review of weight control registries

Weight loss maintenance is a major challenge for obesity treatment. Weight control registries can be useful in identifying psychological and behavioural factors that could contribute to better long‐term success. The objective of this study is to describe the existing weight control registries and their participants and identify correlates of weight loss maintenance. A comprehensive search of peer‐reviewed articles published until November 2018 was conducted in PubMed, Web of Science, and Scopus. Studies that reported results from weight control registries were considered. Fifty‐two articles, corresponding to five registries (the United States, Portugal, Germany, Finland, and Greece), were included. Registries differed in inclusion criteria and procedures. Of 51 identified weight loss and maintenance strategies, grouped in 14 domains of the Oxford Food and Activity Behaviors taxonomy, the following were the most frequently reported: having healthy foods available at home, regular breakfast intake, increasing vegetable consumption, decreasing sugary and fatty foods, limiting certain foods, and reducing fat in meals. Increased physical activity was the most consistent positive correlate of weight loss maintenance. To our knowledge, this is the first systematic review of information about successful weight loss maintenance obtained from weight control registries. Key common influential characteristics of success were identified, which can inform future prospective studies and weight management initiatives.