Summary: This overview of reviews aimed to summarize the effects of exercise training programs on weight loss, changes in body composition, and weight maintenance in adults with overweight or obesity. A systematic search of systematic reviews and meta‐analyses (SR‐MAs) published between 2010 and December 2019 was performed. Only SR‐MAs of controlled trials were included. The mean difference (MD) or standardized MD (SMD) were extracted from SR‐MAs. Twelve SR‐MAs (149 studies) were included. Exercise led to a significant weight loss (4 SR‐MAs, MDs ranging from −1.5 to −3.5 kg), fat loss (4 SR‐MAs, MDs ranging from −1.3 to −2.6 kg) and visceral fat loss (3 SR‐MAs, SMDs ranging from −0.33 to −0.56). No difference in weight, fat, and visceral loss was found between aerobic and high‐intensity interval training as long as energy expenditure was equal. Resistance training reduced lean mass loss during weight loss (1 SR‐MA, MD: 0.8 [95%CI: 0.4–1.3] kg). No significant effect of exercise was found on weight maintenance (1 SR‐MA). These findings show favorable effects of exercise training on weight loss and body composition changes in adults with overweight or obesity. Visceral fat loss may lead to benefits for cardiometabolic health. More research is needed to identify training modalities that promote weight maintenance.

Summary: There is a need for updated practice recommendations on exercise in the management of overweight and obesity in adults. We summarize the evidence provided by a series of seven systematic literature reviews performed by a group of experts from across Europe. The following recommendations with highest strength (Grade A) were derived. For loss in body weight, total fat, visceral fat, intra‐hepatic fat, and for improvement in blood pressure, an exercise training program based on aerobic exercise at moderate intensity is preferentially advised. Expected weight loss is however on average not more than 2 to 3 kg. For preservation of lean mass during weight loss, an exercise training program based on resistance training at moderate‐to‐high intensity is advised. For improvement in insulin sensitivity and for increasing cardiorespiratory fitness, any type of exercise training (aerobic, resistance, and combined aerobic or resistance) or high‐intensity interval training (after thorough assessment of cardiovascular risk and under supervision) can be advised. For increasing muscular fitness, an exercise training program based preferentially on resistance training alone or combined with aerobic training is advised. Other recommendations deal with the beneficial effects of exercise training programs on energy intake and appetite control, bariatric surgery outcomes, and quality of life and psychological outcomes in management of overweight and obesity.

Summary: This systematic review examined the effect of exercise training interventions on physical fitness in adults with overweight or obesity and compared the effectiveness of different types of exercise training. Four electronic databases were searched. Articles were included if they described randomized controlled trials of exercise training interventions and their effect on maximal oxygen consumption or muscle strength in adults with overweight or obesity. Changes in outcome parameters were analyzed using random effects meta‐analyses for different training types (aerobic, resistance, combined aerobic plus resistance, and high‐intensity interval training). Eighty‐eight articles satisfied the inclusion criteria of which 66 (3964 participants) could be included in the meta‐analyses. All training types increased VO_2max (mean difference 3.82 ml/min/kg (95% CI 3.17, 4.48), P < 0.00001; I² = 48%). In direct comparisons, resistance training was less effective in improving VO_2max than aerobic training, HIIT was slightly more effective than aerobic training, and no difference between aerobic and combined aerobic plus resistance training was found. For muscle strength benefits, incorporation of resistance exercise in the training program is indicated. Exercise training increases VO_2max and muscle strength in adults with overweight or obesity. Differences between training types should be weighed with other needs and preferences when health professionals advise on exercise training to improve physical fitness.

Summary: We aimed to assess the effectiveness of exercise training programs in adults with severe obesity undergoing bariatric surgery. A systematic search of controlled trials published up to October 2019 that assigned participants to either a preoperative or postoperative exercise training group or a nonexercise group was performed. Meta‐analyses were conducted using random‐effects models. Twenty‐two training programs were assessed (18 performed after bariatric surgery). The effect of preoperative exercise training on postsurgery outcomes was reported in only one study. Compared with the control condition without exercise, postoperative exercise training led to higher weight loss (N = 14, mean difference [95% CI] = −1.8 [−3.2; −0.4] kg,P = 0.01), fat loss (N = 9,P = 0.01), increase in VO₂max (N = 8,P < 0.0001), and increase in muscle strength (N = 9,P < 0.0001). No significant effect was found on lean body mass (N = 11). Preliminary evidence suggests a beneficial effect of postoperative exercise training on bone mineral density (N = 3,P < 0.001) and weight maintenance after the end of the intervention (N = 2,P < 0.001) but no significant effect on quality of life (N = 2), habitual physical activity (N = 2), or cardiometabolic outcomes (N < 4). In conclusion, exercise training performed after bariatric surgery improves physical fitness and leads to a small additional weight and fat loss and may prevent bone loss and weight regain after bariatric surgery.