According to nutrition consultant Dr. Lisa Young, maintaining a healthy weight isn't so much about what you eat but rather how much you eat. Dr. Young, author of The Portion Teller: Smartsize Your Way to Permanent Weight Loss, shares with Peter her tips to help you control your portion sizes:

• Learn the proper portion size of different foods. For example, a healthy portion size of steak should be about two decks of cards. A good portion size for a side of rice or pasta should be about the same size as a baseball or a fist (one cup).
• Order salads with the dressing on the side. Use two tablespoons, or about one shot-glass full, of salad dressing.
• Eat just half an entree. When ordering out at restaurants, ask your waiter to box half your meal before bringing it to your table.