Dietary restriction combined with endurance exercise training represents an effective strategy to promote weight loss and reduce fat mass in obese patients. Exercise programmes without dietary restriction are less efficient. However, addition of exercise to a dietary restriction programme does not induce a greater fat-mass loss than dietary restriction alone. The latter is likely attributed to a compensatory reduction in daily physical activity following the implementation of exercise training. Nonetheless, inclusion of an exercise training programme is important to prevent a decrease in fat-free mass, increase relative visceral fat-mass loss, improve dietary compliance and eventually maintain long-term weight control. Obese male patients with the highest fat mass are most likely to lose the largest amount of fat mass in such lifestyle intervention programmes. Influences of training modalities during energy intake restriction on fat-mass loss are reviewed. The relationship between total energy expenditure during exercise training and overall fat-mass loss has been firmly established. The amount of training forms a more important predictor of fat-mass loss than training intensity. The sort of exercise (e.g. walking, cycling, swimming) plays another important predictor of fat-mass loss in intervention programmes. The implementation of resistance training in such programmes does not augment fat-mass loss but improves body composition by increasing fat-free mass. Further studies are needed to define the optimal interventional programme for obese patients. AD - Human Physiology and Sports Medicine, Vrije Universiteit Brussel (VUB), Faculty LK, Brussels, BelgiumRehabilitation and Health Centre, Virga Jesse Hospital, Hasselt, Belgium.