Cycling-Based HIIT Versus MICT for Weight and Fat Loss in Obese Adults: A Meta-Analysis

Background: Evidence comparing high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) for obesity remains inconsistent, particularly with respect to cycling-based protocols. Therefore, this meta-analysis aimed to evaluate randomized controlled trials comparing bicycle-ergometer HIIT with cycling-based MICT in adults with overweight or obesity. Methods: PubMed, Scopus, Cochrane Library, and Google Scholar were searched from January 2015 to September 2025; Google Scholar was used as a supplementary source. Eligible studies included adults aged 18–60 years and compared cycling-based HIIT with MICT interventions conducted over a minimum duration of 5 weeks. The primary outcomes were changes in body mass and fat mass. Between-group standardized mean differences (SMDs) were pooled using random-effects models. Results: Nine RCTs involving 394 enrolled participants were included, although analyzable samples varied by outcome. No significant between-group difference was observed for body mass (SMD: 0.04; 95% CI: −0.19 to 0.27; p = 0.710; I2 = 0%; τ2 = 0.00) or fat mass (SMD: 0.01; 95% CI: −0.23 to 0.26; p = 0.810; I2 = 0%; τ2 = 0.00). The pooled effects were close to zero and should be interpreted as short-term findings because interventions lasted 5–12 weeks. Conclusion: Current evidence from randomized controlled trials does not demonstrate the superiority of either cycling-based HIIT or MICT for reducing body mass or fat mass in adults with overweight or obesity. These findings do not establish equivalence and should therefore be interpreted with caution, given the small sample sizes, short follow-up, limited dietary control, and possible measurement error in body-composition outcomes.