Five-hundred calorie diets are among the most radical and effective weight loss interventions for people who are obese. "The International Journal of Obesity" reported that very low calorie diets (VLCDs) result in rapid weight loss, averaging about 4-1/2 lbs. per week--a rate generally seen only in people who have recently undergone weight loss surgery. Five-hundred calorie diets are widely considered to be effective alternatives to weight loss surgery and stimulant drugs.
For people who are only moderately overweight, the risks of 500-calorie diets outweigh the benefits. VLC diets cause headache, fatigue and other mild discomforts, and "The American Journal of Clinical Nutrition" reports that VLCDs increase the risk of gallstones and liver disease.
Very Low-Calorie Dieting
Determine the amount of time that you will spend on the 500-calorie diet (your doctor or dietician can help you to make this decision). In general, 500-calorie diets should not be pursued for more than two weeks; after this point, the risks increase and the benefits begin to diminish.
Purchase a complete nutrition shake, either in the form of a powdered mix or a pre-made drink. These contain a full spectrum of essential vitamins and minerals, as well as fiber and a complete protein source (such as whey, casein or soy). VLCD nutrition shakes should contain some source of carbohydrates, which are essential for preventing serious metabolic complications. Note that while some VLCDs use solid food, these are nutritionally imbalanced and may increase the likelihood of complications.
Divide the nutrition shake into four to ten servings for a total of 500 calories per day. For example, a VLC dieter may have 100 calories of shake in the morning, 50 at brunch, 100 at noon, 50 in the afternoon, 175 at dinner and 25 before bed. If necessary, dilute the shake with water or blend it with ice to expand its volume.
Drink at least 1 gallon of water per day. This can prevent constipation, a common side effect among people consuming 500-calorie diets.
Discontinue the 500-calorie diet after the pre-established amount of time. To avoid regaining lost weight, gradually adjust to a regular reduced-calorie dietary lifestyle. Eat fruits, vegetables, whole grains and legumes, and avoid heavily processed foods.