Physical activity and exercise for weight loss and maintenance in people living with obesity.

Physical activity and exercise training programs are integral part of a comprehensive obesity management approach. In persons with overweight or obesity, exercise training, specifically aerobic (i.e. endurance) training, is associated with significant additional weight loss compared to the absence of training. However the magnitude of effect remains modest amounting to only 2-3 kg additional weight loss on average. Comparable effects have been observed for total fat loss. Exercise training, specifically aerobic training, is also associated with decreased abdominal visceral fat as assessed by imaging techniques, which is likely to benefit cardiometabolic health in persons with obesity. Based on data from controlled trials with randomization after prior weight loss, the evidence for weight maintenance with exercise training is as yet not conclusive, although retrospective analyses point to the value of relatively high-volume exercise in this regard. Resistance (i.e. muscle-strengthening) training is specifically advised for lean mass preservation during weight loss. Given the relatively limited effect of exercise training on weight loss as such, the changes in physical fitness brought about by exercise training cannot be overlooked as they provide major health benefits to persons with obesity. Aerobic, as well as combined aerobic and resistance training, increase cardiorespiratory fitness (VO_2max) while resistance training, but not aerobic training, improves muscle strength even in the absence of a significant change in muscle mass. Regarding the overall management strategy, adherence in the long term to new lifestyle habits remains a challenging issue to be addressed by further research.