Sleep at least 7 hours a night. Eliminate all sources of light from your bedroom. Get to bed at least 8 hours before you expect to wake up, and spend the last hour before that relaxing with the lights turned down. When you sleep better, you’ll have more energy, and thus move more and burn more calories. Your body will regulate it’s appetite better. Your hormonal profile will improve, allowing you to build more muscle and burn more fat, independent of diet and exercise.
In a way, moderate-intensity physical activity is that "magic pill" a lot of people are looking for, because the health benefits go beyond keeping your waistline trim: Not only can it reduce your risk of cancer, stroke, diabetes and heart attacks, but studies have shown that physical activity can significantly improve the moods of patients with major depressive disorders.