Nutrition 101 Part 6 from Registered Dietitian Joan OKeefe:

Joan O'Keefe discusses some tips on healthy meals and snacking for people trying to lose weight. O'Keefe explains that it's important that you only eat when you feel a gnawing feeling. This gnawing feeling is your body's mechanism of letting you know when it needs food. Eating without feeling hungry means you are eating more than your body needs. O'Keefe also gives three rules to guide your weight loss plan. The gnawing feeling is an indicator that fat storage is being tapped. This means weight loss! Another tip that O'Keefe provides is that people on a weight loss plan should eat between 9 and 11 servings of fruit and vegetables each day. Getting the gnawing feeling in between meals calls for a small snack consisting of fruits and vegetables, cottage cheese, low fat yogurt or a handful of nuts. However, if you are craving a snack and don't have that gnawing feeling, she suggests you distract yourself by taking a walk, shooting some hoops, starting a project, reading the mail, etc.