Jim said people can healthily lose half a pound to two pounds a week. In a month, that could add up to four to eight pounds lost. Since one pound of fat equals 3,500 calories, to lose one pound a week, you would have to burn approximately 500 extra calories a day. This can be achieved through eating in a healthy calorie deficit or working out to burn extra calories (or a combination of both). Other lifestyle factors also play a role. Getting enough sleep will ensure your body recovers well and that you'll be energized for your workouts the next day. And too much stress increases the stress hormone cortisol, which can increase your cravings for caloric refined carbs and comfort food, which will prevent you from losing weight (especially in your belly). Make sure, in addition to eating in a calorie deficit, that you're also getting at least seven hours of sleep a night and managing your stress.
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.