1. The diet should be safe. It should include all of the Recommended Daily Allowances (RDAs) for vitamins, minerals, and protein. The weight-loss diet should be low in calories (energy) only, not in essential foodstuffs.
   
2. The weight-loss program should be directed towards a slow, steady weight loss unless your doctor feels your health condition would benefit from more rapid weight loss. Expect to lose only about a pound a week after the first week or two. With many calorie-restricted diets there is an initial rapid weight loss during the first I to 2 weeks, but this loss is largely fluid. The initial rapid loss of fluid also is regained rapidly when you return to a normal-calorie diet. Thus, a reasonable goal of weight loss must be expected.
   
3. If you plan to lose more than 15 to 20 pounds, have any health problems, or take medication on a regular basis, you should be evaluated by your doctor before beginning your weight-loss program. A doctor can assess your general health and medical conditions that might be affected by dieting and weight loss. Also, a physician should be able to advise you on the need for weight loss, the appropriateness of the weight-loss program, and a sensible goal of weight loss for you. If you plan to use a very-low-calorie diet (a special liquid formula diet that replaces all food intake for I to 4 months), you definitely should be examined and monitored by a doctor.
   
4. Your program should include plans for weight maintenance after the weight loss phase is over. It is of little benefit to lose a large amount of weight only to regain it. Weight maintenance is the most difficult part of controlling weight and is not consistently implemented in weight-loss programs. The program you select should include help in permanently changing your dietary habits and level of physical activity, to alter a lifestyle that may have contributed to weight gain in the past. Your program should provide behavior modification help, including education in healthy eating habits and long-term plans to deal with weight problems. One of the most important factors in maintaining weight loss appears to be increasing daily physical activity, often by sensible increases in daily activity, as well as incorporating an individually tailored exercise program.

A commercial weight-loss program should provide a detailed statement of fees and costs of additional items such as dietary supplements.