Cookie diet refers to a low-calorie diet based on a hunger-controlling meal replacement in the form of a cookie. There are a number of cookie diets currently on the market, such as the Smart for Life Cookie Diet, Dr. Siegal’s Cookie Diet, Hollywood Cookie Diet and R&D Diet Cookie. All require 4 to 6 cookies per day, sometimes in addition to other food, such as one meal of six ounces of meat in the case of the Siegal diet.