Special K is an American brand of breakfast cereal and meal bars manufactured by Kellogg's. The cereal was introduced to the United States in 1955. It is made primarily from grains such as lightly toasted rice, wheat and barley. Special K used to be marketed primarily as a low-fat cereal that can be eaten to help one lose weight. Special K Challenge The Special K brand previously advocated the "Special K Challenge." The goal of this challenge was to help an individual lose six pounds in two weeks; this loss was achieved by eating specific Special K products throughout the day. The diet began with a single serving of any Special K cereal, accompanied with 2/3 cup of skim milk and a side of fruit. The second meal of the diet included either a Special K Protein Meal Bar, Special K Protein Shake, or another serving of Special K cereal with 2/3 cup of skim milk and a side of fruit. The third meal of the day could be consumed normally, without any Special K restrictions. Throughout the day, an individual is allotted two Special K snacking times, eating any of the following specified snacks: Special K Protein Meal Bars, Special K Protein Shakes, Special K Breakfast Shakes, Special K Protein Granola Bars, Special K Crackers, Special K Cracker Chips, or Special K Popcorn. For any additional snack servings, an individual could consume fruits and vegetables. During the challenge, drinks could be consumed normally. Critics of the Special K diet feel that it may leave dieters feeling hungry because of its limited food options and deter people from sticking to the diet. The diet has been criticised for being too low in protein, fiber, vegetables, and fruits. The diet does not include guidance on how to change unhealthy overeating or lack of exercise and their importance to permanent weight loss. Nutrition In the United States, Special K Original has 120 calories per 31g cup serving. One serving contains 0.5g fat, 23g carbohydrates, 4g sugar, and 6g protein. In the United Kingdom, Special K Original is 17% sugar, meaning a 30g serving contains 5g of sugar. In the UK, an advertising campaign has focused on the results of a study run in collaboration with the Department of Human Sciences at Loughborough University, requiring overweight volunteer subjects to replace two meals a day with a bowl of the cereal. The study found