Fat

Utilization Energy Body structure Cell membranes Protection Essential fatty acids Hormones & bile salts Vitamin Carrier (Fat soluble vitamins A, D, E) Palatability & satiety of foods Types of Dietary Fat Polyunsaturated and monounsaturated fats are preferred in the diet Found in fish, nuts, vegetable oils Contain essential fatty acids which help to reduce cholesterol deposits Omega 3 fatty acids 2 serving (8 oz) of fish (low mercury) per week recommended Saturated fats can be converted to cholesterol or LDL See Saturated Fats Exchanges and Additional Fat Exchanges Trans-unsaturated fat may act like saturated fat, eg: margarine, hydrogenated oil. Processed foods and oils provide 80% of trans fats in diet Animal sources only provide 20% of trans fats (naturally occurring) in diet Also see Comparison of Dietary Fats American Dietary Guidelines (2005) A high fat intake (greater than 35% of calories) associated with higher saturated fat intake keep saturated fat below 10% of calories more difficult to avoid consuming excessive calories Low fat intake (less than 20% of calories) increased risk of inadequate intakes of vitamin E and essential fatty acids may contribute to unfavorable changes in HDL and triglycerides Weight Management Dietary fats are stored and mobilized easily It takes more energy for the body to convert carbohydrates or protein to body fat than it does to convert dietary fat to body fat see thermic effect of food Typically, less calories are consumed when eating a low fat diet (Lissner 1987, Thomas 1992). A reduction in dietary fat without a reduction in total calories or an increase of physical activity only produces small if any changes in body fat mass (Leibel 1992). Effects on Endurance High fat diets may limit endurance if carbohydrates are low and body is accustome to a higher carbohydrate diet. A high fat diet may actually increase endurance in certain elite athletes particularly if they have adapted to such a diet Studies are mixed as to whether it increases endurance Ideal would be fat adaptation with high glycogen and intramuscular triglyceride stores Fat adaptation occurs after five days of being on the high fat diet and persists during one day of carbing up (Burke 2000) There is no net glucose synthesis from lipids except from glycerol portion - 10% by weight