A low-fat diet is one that restricts fat, and often saturated fat and cholesterol as well. Low-fat diets are intended to reduce the occurrence of conditions such as heart disease and obesity. For weight loss, they perform similarly to a low-carbohydrate diet, since macronutrient composition does not determine weight loss success. Fat provides nine calories per gram while carbohydrates and protein each provide four calories per gram. The Institute of Medicine recommends limiting fat intake to 35% of total calories to control saturated fat intake. Although fat is an essential part of a person's diet, there are "good fats" and "bad fats." Knowing the difference can help a person make informed choices about their meals. If you're following a healthy, balanced diet, restricting your fat intake is generally unnecessary. However, under certain circumstances, limiting the fat in your diet may be beneficial. For example, low-fat diets are recommended if you're recovering from gallbladder surgery or have gallbladder or pancreas disease. Low-fat diets may also prevent heartburn, cut weight and improve cholesterol.