A kind of diet is a way of eating that is designed to promote health or weight loss. Paleo is a diet that focuses on eating foods that were available during the Paleolithic era, such as LEAN meats, fruits, and vegetables. FAD diets are short-term diets that often involve drastic changes in eating habits and are not sustainable in the long run. LEAN diets emphasize eating LEAN proteins, such as fish and poultry, and avoiding processed foods. CRASH diets involve severely limiting calorie intake for a short period of time in order to achieve rapid weight loss. Nofat diets eliminate all fat from the diet, while nosalt diets eliminate all salt from the diet. The Scarsdale diet is a low-carbohydrate, high-protein diet that was popular in the 1970s.