Despite the fact that too much fat can be harmful, a moderate fat intake is actually essential to the maintenance of good health. Some of the symptoms of fat deficiency include flaking skins, emaciation, reduced functioning of the immune system, and fertility problems. Recent studies have linked fat free diets to increase stress and aggression, and note that those who try to eliminate fat completely from their food intake may be at risk for developing eating disorders: a small amount of fat in a meal will produce a feeling of satiety which lasts much longer than the sensation of fullness produced by protein or carbohydrates.