There are no magic diets, pills, or operations for long-term, healthy weight loss. A useful approach is to select the best diet that works for you. This is the eating plan you can live with. A total of 3500 calories equals 1 pound of body weight. This means if you decrease (or increase) your intake by 500 calories daily, you will lose (or gain) 1 pound per week. (500 calories per day × 7 days = 3500 calories.) All foods have carbohydrate, protein, and fat. Carbohydrates provide 4 calories per gram. Proteins provide 4 calories per gram. Fats provide 9 calories per gram. Carbohydrates are either simple or complex. Simple carbohydrates cause more weight gain than complex carbohydrates. Simple carbohydrates include sugar and starches (potatoes, pasta, and rice). Complex carbohydrates include fruits, vegetables, and whole grains.