There are a few diet plans that may be referred to as the "Cookie Diet." In general a cookie diet uses hunger-controlling cookies to replace meals as part of a low calorie diet. Cookie diets are typically very low calorie and designed for significant weight loss, often over a short-term period.

The oldest cookie diet is Dr. Siegel's® Cookie Diet^TM, developed by South Florida physician Dr. Sanford Siegal for his patients in 1975. His plan consists of six cookies a day and a dinner or chicken or fish with vegetables. Because it is very low calorie, people who wish to follow Dr. Siegel's® Cookie Diet^TM must consult a doctor and develop their diet plan with his or her help. However, one may simply use the cookies to replace less healthy snacks. Dr. Siegel now offers soups and shakes in addition to his cookies.

Another weight loss program that uses cookies is Smart for Life^TM. It was founded by Dr. Sasson Moulavi in partnership with Dr. Siegel in 2002, but has not been affiliated with Dr. Siegel since 2006. The cookies used in Smart for Life^TM do not use Dr. Siegel's recipe, but the diet plan itself is nearly identical.

Smart for Life^TM differs from Dr. Siegel's® Cookie Diet^TM in that it emphasizes developing healthy behaviors and attitudes about food that will last one's lifetime. It also incorporates exercise, supplements, and vitamin injections in addition to the diet itself. Medical supervision is required for the Smart for Life^TM program.

The newest cookie diet on the scene is the Hollywood Cookie Diet®, endorsed by celebrities and on popular television shows. The Hollywood Cookie Diet® plan is similar to the two described above, consisting of four cookies a day and a dinner of lean protein and vegetables. The cookies are available without a prescription through the Internet and at pharmacies. The Hollywood Cookie Diet® website offers free dinner recipes and free diet coaching. As with Dr. Siegel's® Cookie Diet^TM, there is no exercise component to the Hollywood Cookie Diet®.

All of the diets described above should only be begun after consultation with a doctor. The fact that they are extremely restrictive, not to mention expensive, means that they are only suitable for short-term weight loss. Smart for Life^TM offers a maintenance program after the initial loss of weight. Both diet and exercise are required for healthy weight loss, so make sure to include an exercise plan with any diet you embark upon.