Thinking of hitting the gym to maintain weight? Scientists say exercise may not help you keep those extra kilos at bay, contradicting the belief that lack of physical activities or increased sedentary time is linked to obesity. Physical activity has many proven health benefits, ranging from reducing the risk of heart disease, diabetes and cancer to improving mental health and mood. People who are physically active tend to be healthier and live longer. However, while physical activity burns calories, it also increases appetite and people may compensate by eating more or by being less active the rest of the day.