Lost weight is less likely to return when exercise follows obesity treatment

Exercise may offer a modest but measurable defense against weight regain after dieting or bariatric surgery, but the evidence is less clear on whether it meaningfully 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 Reports, a group of researchers evaluated whether exercise interventions during the weight-maintenance phase can reduce weight regain after successful weight loss.

Background

Many individuals who successfully lose weight eventually regain some of that weight, making long-term weight management one of the greatest challenges in obesity care. Weight regain is common after dietary interventions, medications, 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, preserves fat-free mass, and improves metabolic health. Yet evidence regarding its effectiveness during post-weight-loss maintenance 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 were conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and were prospectively registered in the International Prospective Register of Systematic Reviews under registration number CRD420251240526. Reviewers conducted a systematic literature search across PubMed, Embase, Web of Science, the Cochrane Library, and the 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 of adults with overweight or obesity (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 regain was defined as the net change in body weight at the end of the maintenance phase relative to the initial pre-weight-loss baseline, rather than only the regain from the lowest post-weight-loss weight. 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. The assessment identified some concerns and high-risk judgments in several domains, which should temper confidence in the evidence. Statistical analyses were performed using Review Manager (RevMan) version 5.4, with risk ratios or mean differences reported with 95% confidence intervals (CIs). Random-effects models served as the primary analytical approach because clinical and methodological differences among 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 enrolled only men or only women, while mixed-sex studies generally included more women than men.

Weight loss prior to the maintenance phase had occurred through either bariatric surgery or very low-calorie diets in the final included trials. Different forms of exercise added to participants' routine included resistance training, aerobic fitness training, walking, cycle ergometry, and deep-water running (aqua jogging). Intervention durations ranged from 12 to 53 weeks, and the majority of studies reported high participant completion rates, which generally indicate good adherence; however, adherence definitions varied across trials.

The body-weight analysis included 9 studies and showed no statistical heterogeneity, despite differences in participants, weight-loss pathways, exercise modalities, and duration. The pooled analysis demonstrated that participants who engaged in exercise 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.

The fat-mass analysis consisted of six studies. Overall, there was no statistically significant difference in fat mass between the exercise group and the control. The exercise groups showed a greater average fat-mass reduction, but the confidence interval crossed zero (mean difference of −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. While the fixed-effect analysis indicated a statistically significant loss of fat mass, the 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 risk ratio was 0.94 (95% CI: 0.85 to 1.03), which indicated no statistically significant difference. There was moderate heterogeneity, and the funnel plot showed a generally symmetric distribution of studies with only slight asymmetry. Since 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 post-weight-loss maintenance phase provided a small but statistically significant benefit in reducing weight regain. The pooled body-weight 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 risk-of-bias concerns limit certainty about the optimal exercise type, dose, and durability of benefit.

In contrast, evidence regarding reductions in fat mass remained inconclusive, as the pooled effect was not statistically significant and heterogeneity across studies persisted. The findings suggest that exercise can help individuals maintain weight loss after successful treatment, although its effects on body composition require further clarification through longer and more standardized randomized controlled trials.

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Journal reference:

• Wang, J., Chen, Y., Xu, K., & Dai, J. (2026). The effects of exercise interventions on weight regain after weight loss: A systematic review and meta-analysis. Scientific Reports article in press. DOI: 10.1038/s41598-026-57804-8, https://www.nature.com/articles/s41598-026-57804-8