The study will investigate whether physical exercise, or dietary restrictions, or a combination of both, among overweight and obese postpartum women lead to a significantly larger reduction in weight in a longer perspective, compared to similar women not receiving the intervention. The study also will investigate the effects on body composition, cardiovascular fitness, blood lipids, insulin levels and inflammation markers. In total, 68 women with pre-pregnancy BMI 25 - 34.9 will be randomized at 10 wk postpartum into: (1) physical exercise, (2) dietary restrictions, (3) physical exercise + dietary restrictions and (4) control group. The intervention lasts for 12 wk and longterm effects are measured 1 yr after trial initiation. To date only studies showing short term (12 wk) effects exist. Our study is the first to include four intervention groups, so that separate effects of physical activity and dietary restriction and their interaction, can be assessed. Further, the investigators will estimate effects on body composition taking body water into account and estimate total energy expenditure with higher precision than previously. Overweight and obesity is an escalating problem in Sweden. Sustainable weight reduction programs are urgently needed. During the postpartum period, women may be motivated to lose weight. Information aimed at promoting life style changes among overweight and obese women could in a longer perspective be integrated in the regular maternal health care in Sweden.