Summary: The purpose of this systematic review and meta‐analysis was to estimate the prevalence of personal weight control attempts (weight loss and/or maintenance) worldwide and to identify correlates, personal strategies used and the underlying motives. We included epidemiological/observational studies of adults (≥18 years) reporting prevalence of weight control attempts in the past‐year. Seventy‐two studies (n = 1,184,942) met eligibility criteria. Results from high quality studies showed that 42% of adults from general populations and 44% of adults from ethnic‐minority populations reported trying to lose weight, and 23% of adults from general populations reported trying to maintain weight annually. In general population studies, higher prevalence of weight loss attempts was observed in the decade of 2000–2009 (48.2%), in Europe/Central Asia (61.3%) and in overweight/obese individuals and in women (p < 0.01). Of the 37 strategies (grouped in 10 domains of the Oxford Food and Activity Behaviours Taxonomy) and 12 motives reported for trying to control weight, exercising and dieting (within the energy compensation and restraint domains, respectively) and wellbeing and long‐term health were the most prevalent. To our knowledge, this is the first systematic review to investigate weight control attempts worldwide. Key strategies and motives were identified which have implications for future public health initiatives on weight control.

Intermittent fasting (IF) has been studied in athletes during Ramadan and in those willing to decrease adiposity while maintaining or increasing lean body mass. The purpose of this systematic review was to summarize the effects of IF on performance outcomes. We searched peer-reviewed articles in the following databases: PubMed, Web of Science and Sport Discus (up to December 2019). Studies were selected if they included samples of adults (≥18 years), had an experimental or observational design, investigated IF (Ramadan and time-restricted feeding (TRF)), and included performance outcomes. Meta-analytical procedures were conducted when feasible. Twenty-eight articles met the eligibility criteria. Findings indicated that maximum oxygen uptake is significantly enhanced with TRF protocols (SMD = 1.32, p = 0.001), but reduced with Ramadan intermittent fasting (Ramadan IF; SMD = −2.20, p < 0.001). Additional effects of IF may be observed in body composition (body mass and fat mass). Non-significant effects were observed for muscle strength and anaerobic capacity. While Ramadan IF may lead to impairments in aerobic capacity, TRF may be effective for improving it. As there are few studies per performance outcome, more research is needed to move the field forward.

Weight loss maintenance is crucial for obesity management, yet optimal dietary patterns for this period are not established. We aimed to explore the relationship between adherence to the Mediterranean diet and weight loss maintenance. Sample includes 565 adults (62 % women) of the MedWeight study. Eligible volunteers were those reporting intentional weight loss of ≥10 %, starting from a BMI ≥ 25 kg/m², over 12 months prior to enrolment. Based on current weight, participants were characterised as maintainers (≤90 % maximum weight) or regainers (>95 % maximum weight). Socio-demographics and weight history were recorded. Dietary intake was assessed by two non-consecutive 24-h recalls within 10 d and analysed in energy, macronutrient and food group intakes. Adherence to the Mediterranean diet was assessed with the Mediterranean Diet Score (MedDietScore) (range 0–55, greater scores showing higher adherence). Protein intake was higher in maintainers than in regainers (P< 0·001). When MedDietScore quartiles were considered, a linear trend for weight loss maintenance was revealed (P< 0·05). After adjustment for basic demographic characteristics, being in the third or fourth quartile of the MedDietScore (v. first) was associated with 2·30 (95 % CI 1·29, 4·09) and 1·88 (95 % CI 1·10, 3·22) increased odds of maintenance. Regarding individual MedDietScore components, only fruit intake is associated with increased odds for maintenance (1·03 (95 % CI 1·01, 1·06)). The leave-one-out approach revealed that at least six MedDietScore components were essential for the observed relationship. Higher adherence to the Mediterranean diet was associated with 2-fold increased likelihood of weight loss maintenance. Future studies should replicate these findings in non-Mediterranean populations as well.

Objective: Systematically identifying pretreatment characteristics that predict successful weight management is important to improve intervention efficacy and clinical practice. This study provides a comprehensive update of a 2005 review on pretreatment predictors of successful weight management. Methods: Results of 37 recent original studies from peer-reviewed journals were merged with the results from the 2005 review. A critical appraisal of the 66 studies included was provided, and meta-analyses were performed when feasible. Results: Fewer previous weight loss attempts were the most consistent pretreatment predictor of successful weight management, although with a small effect size. Importantly, several variables were identified as non-significant predictors of weight loss, showing trivial effects (e.g., eating self-efficacy). Many psychosocial factors remain too little studied to allow reliable conclusions regarding their predictive value. Conclusion: Previous dieting attempts were identified as the soundest predictor of successful weight management. Several factors, previously considered barriers to successful weight management and now identified as non-predictors, require more investigation given the limitations identified in this review. Importantly, due to a comparably thin empirical basis for many predictors, further research is essential to move the field forward. Implications of the current state of research and necessary steps to improve intervention efficacy and clinical practice are discussed

Purpose: Theory-based interventions aimed at promoting health behavior change in cancer survivors seem to be effective but remain scarce. More information on intervention features is also needed. This review aimed to synthesize the evidence from randomized controlled trials evaluating the efficacy of theory-based interventions (and its features) on physical activity (PA) and/or diet behaviors in cancer survivors. Methods: A systematic search in three databases (PubMed, PsycInfo, and Web of Science) identified studies that (i) targeted adult cancer survivors and (ii) included theory-based randomized controlled trials designed to influence PA, diet, or weight management. A qualitative synthesis of interventions’ effectiveness, extensiveness of theory use, and applied intervention techniques was conducted. Results: Twenty-six studies were included. Socio-Cognitive Theory was the most used theory, showing promising results in PA-only trials and mixed findings in multiple-behavior interventions. Mixed findings were observed for interventions based on the Theory of Planned Behavior and Transtheoretical Model. Limited findings were found in diet-only interventions. A large variability in the extensiveness of theory use, and in intervention techniques was found. Further research is required to understand how and why these interventions offer promise for improving behavior. Conclusions: Theory-based interventions seem to improve PA and diet behaviors in cancer survivors. Further studies, including thorough intervention descriptions, are needed to confirm these findings and identify the optimal features and content of lifestyle theory-based interventions for cancer survivors. Implications for Cancer Survivors: This systematic review can contribute to the development of more effective interventions to promote long-term adherence to healthy lifestyle behaviors.