Exercise may have a modest but measurable protective effect against weight gain after dieting or bariatric surgery, but the evidence is less clear as to whether it significantly reduces fat mass.
Research: 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 published as a press article in the journal scientific reportA group of researchers evaluated whether exercise intervention during the weight maintenance phase could 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 after dietary interventions, medications, and bariatric surgery is common and is often caused by physiological and behavioral adaptations that promote increased energy storage and appetite. Exercise is often recommended as a component of weight management because it increases energy expenditure, maintains lean body mass, and improves metabolic health. However, evidence regarding its effectiveness in the post-weight loss maintenance period remains inconsistent across studies and intervention types. Further research is needed to clarify its contribution to long-term weight maintenance.
About research
This systematic review and meta-analysis was conducted in accordance with Preferred Reporting Items guidelines for systematic reviews and meta-analyses and was prospectively registered in the International Prospective Register of Systematic Reviews with registration number CRD420251240526. Reviewers conducted a systematic literature search from inception to October 19, 2025 across PubMed, Embase, Web of Science, the Cochrane Library, and China National Knowledge Infrastructure using controlled vocabulary and free-text terms related to exercise, weight loss, weight maintenance, weight regain, and overweight.
Eligible studies include English language randomized controlled trials in overweight or obese (BMI > 25 kg/m²) adults who have already achieved weight loss through dietary restriction, pharmacotherapy, bariatric surgery, or other methods. Studies were required to evaluate exercise interventions during the weight maintenance phase and report outcomes related to body weight, body composition, or blood-based measurements.
For this review, weight gain was defined as the net change in weight at the end of the maintenance phase relative to the baseline before the first weight loss, rather than just the recovery from the lowest weight after weight loss. Study selection, data extraction, and risk of bias assessment were performed independently by reviewers using the revised Cochrane Risk of Bias Tool for Randomized Trials. This assessment identified some concerns and high-risk decisions in several areas, which should weaken confidence in the evidence. Statistical analyzes were performed using Review Manager (RevMan) version 5.4, and risk ratios or mean differences were reported with 95% confidence intervals (CI). Due to anticipated clinical and methodological differences between studies, a random-effects model served as the primary analytic approach.
Research results
The literature search identified 1,529 records and removed 441 duplicates. After screening, 11 randomized controlled trials with 568 participants met inclusion criteria. Of the participants, 352 were assigned to the exercise group and 216 to the control group. The study was published between 1996 and 2023 and included participants aged 38.6 to 70 years. Some studies enrolled only men or only women, while mixed-sex studies generally had more women than men participating.
Weight loss before the maintenance phase occurred either through bariatric surgery or a very low-calorie diet in the final included trials. The various exercises added to participants’ daily routines included resistance training, aerobic fitness training, walking, cycle ergometry, and deep water running (aqua jogging). Intervention duration ranged from 12 to 53 weeks, and most studies reported high completion rates among participants, indicating generally good adherence. However, the definition of adherence varied between trials.
Nine studies were included in the weight analysis and showed no statistical heterogeneity despite differences in participants, weight loss routes, exercise methods, and duration. Pooled analyzes demonstrated that participants who engaged in exercise regained significantly less weight than participants in the control group. The mean difference was -2.81 kg, 95% CI: -5.12 to -0.51. Sensitivity analyzes using a fixed effects model yielded the same results, confirming the robustness of the results.
Fat mass analysis consists of six studies. Overall, there was no statistically significant difference in fat mass between exercise groups and controls. The exercise group showed greater mean fat mass loss, 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 across studies in participant demographics, intervention type, duration, and measurement techniques. Although fixed effects analysis showed a statistically significant reduction in fat mass, random effects analysis was preferred due to variability.
These separate studies found no significant differences in adherence between exercise and control groups. The pooled risk ratio was 0.94 (95% CI: 0.85 to 1.03), with no statistically significant difference. There was moderate heterogeneity, and funnel plots showed an overall symmetric distribution of studies with only slight asymmetries. Publication bias could not be reliably assessed as fewer than 10 studies were included in the analysis.
conclusion
This systematic review and meta-analysis found that exercise interventions during the maintenance phase after weight loss had a small but statistically significant effect in reducing weight gain. Accumulated body weight evidence supports that exercise is a useful component of long-term weight management, but small numbers of trials, heterogeneous exercise regimens, variable definitions of adherence, an outdated evidence base, and concerns about risk of bias limit certainty about optimal exercise type, dose, and durability of effects.
In contrast, evidence for fat mass reduction was inconclusive as the pooled effect was not statistically significant and heterogeneity between studies persisted. Although the results of this study suggest that exercise may help maintain weight loss after successful treatment, the effects of exercise on body composition need to be further elucidated through longer, standardized, randomized controlled trials.
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Reference magazines:
- Wang, J., Chen, Y., Xu, K., and Dai, J. (2026). Effects of exercise interventions on weight regain after weight loss: A systematic review and meta-analysis. Scientific Reports article has been published. Doi: https://doi.org/10.1038/s41598-026-57804-8
