Exercise may offer a modest but measurable defense against weight regain after dieting or bariatric surgery, but the evidence is less clear about whether it actually reduces fat mass.
Study: The effects of exercise interventions on weight regain after weight loss: a systematic review and meta-analysis. Image credit: Dragon Images / Shutterstock
In a recent study appearing as an article in press in the journal Scientific Reportsa group of researchers evaluated whether exercise interventions during the weight maintenance phase can reduce weight regain after successful weight loss.
Background
Many people who successfully lose weight eventually regain some of that weight, making long-term weight management one of the biggest challenges in obesity care. Weight regain is common after nutritional interventions, drugs, and bariatric surgery, often driven by physiological and behavioral adaptations that promote energy storage and increased appetite. Exercise is often recommended as a component of weight management because it increases energy expenditure, maintains fat-free mass, and improves metabolic health. However, evidence regarding its effectiveness during maintenance after weight loss remains inconsistent across studies and intervention types. Further studies are needed to clarify its contribution to long-term weight maintenance.
About the Study
This systematic review and meta-analysis was conducted in accordance with the guidelines for Preferred References for systematic reviews and meta-analyses and was prospectively registered in the International Register of Candidate Systematic Reviews under registration number CRD420251240526. The reviewers conducted a systematic literature search in PubMed, Embase, Web of Science, Cochrane Library, and China National Knowledge Infrastructure from inception to October 19, 2025, using controlled vocabulary and free text terms related to exercise, weight loss, weight maintenance, weight regain, and overweight.
Eligible studies included English-language randomized controlled trials in overweight or obese adults (body mass index > 25 kg/m²) who had already achieved weight loss through dietary restriction, pharmacotherapy, bariatric surgery or other methods. Studies were required to evaluate an exercise intervention during the weight maintenance phase and report outcomes related to body weight, body composition or blood-based measures.
In this review, weight recovery was defined as the net change in body weight at the end of the maintenance phase relative to the initial baseline before weight loss, not just the recovery from the lowest weight after weight loss. Study selection, data extraction and risk of bias assessment were performed independently by the reviewers using the revised Cochrane Risk of Bias tool for randomized trials. The assessment identified a number of high-risk concerns and crises in various areas, which should moderate confidence in the evidence. Statistical analyzes were performed using Review Manager (RevMan) version 5.4, with hazard ratios or mean differences reported with 95% confidence intervals (CIs). Random effects models served as the primary analytic approach because clinical and methodological differences between studies were expected.
Study Results
The literature search identified 1,529 records and 441 duplicates were removed. After screening, 11 randomized controlled trials involving 568 participants met the inclusion criteria. Of the participants, 352 were assigned to an exercise group and 216 to the control group. The trials were published between 1996 and 2023, with participants aged 38.6 to 70 years. Some studies included only men or only women, while mixed-sex studies generally included more women than men.
Weight loss prior to the maintenance phase had occurred either through bariatric surgery or a very low-calorie diet in the final included trials. The different forms of exercise added to the participants’ routines included resistance training, aerobic fitness training, walking, cycle ergometry, and deep water running (water jogging). Intervention durations ranged from 12 to 53 weeks, and the majority of studies reported high participant completion rates, which generally indicate good compliance. However, compliance definitions differed between trials.
The body weight analysis included 9 studies and showed no statistical heterogeneity, despite differences in participants, weight loss routes, exercise modalities and duration. Pooled analysis showed that the exercise participants regained significantly less weight than those in the control groups. The mean difference was −2.81 kg, 95% CI: −5.12 to −0.51. Sensitivity analysis using a fixed effect model produced the same result, confirming the robustness of the finding.
Fat mass analysis consisted of six studies. Overall, there was no statistically significant difference in fat mass between the exercise group and the control group. The exercise groups showed a greater mean reduction in fat mass, but the confidence interval exceeded zero (mean difference −3.39 kg, 95% CI = −7.24 to 0.46, P=0.08). There was also considerable variation between studies in participant demographics, type of intervention, duration and measurement techniques. While fixed-effect analysis showed a statistically significant loss of fat mass, random-effects analysis was preferred due to the amount of variability.
None of these individual studies found a significant difference in adherence between the exercise and control groups. The pooled hazard ratio was 0.94 (95% CI: 0.85 to 1.03), showing no statistically significant difference. There was moderate heterogeneity and the funnel plot showed a generally symmetrical distribution of studies with only slight skewness. As fewer than 10 studies were included in the analysis, publication bias could not be reliably assessed.
Conclusion
This systematic review and meta-analysis found that exercise interventions during the maintenance phase after weight loss provided a small but statistically significant benefit in reducing weight regain. Body weight pooled evidence supports exercise as a useful component of long-term weight management, but the small number of trials, heterogeneous exercise prescriptions, variable adherence definitions, older evidence base, and concerns about risk of bias limit certainty about the optimal type of exercise, dose, and duration of benefit.
In contrast, the evidence for reductions in fat mass remained inconclusive, as the pooled effect was not statistically significant and heterogeneity between studies remained. The findings suggest that exercise may help people maintain weight loss after successful treatment, although its effects on body composition require further clarification through longer and more standardized randomized controlled trials.
