Fats are lipid molecules composed of carbon, hydrogen, and oxygen. They include triglycerides, phospholipids, and sterols. Triglycerides are the most common dietary lipid and are composed of a glycerol backbone bonded to three fatty acids. Fatty acids can be saturated or unsaturated and vary in length. Fats serve important functions as energy sources, energy reserves, cushions, insulators, and vitamin carriers. Dietary recommendations suggest obtaining 20-35% of total calories from fats with an emphasis on unsaturated fats and limitation of saturated and trans fats. Cholesterol intake should be limited to less than 300mg per day.

1. Fats Chapter 4

2. What are fats? Lipid molecules Carbon Hydrogen Oxygen Hydrophobic Lipophilic The terms fat and lipid will be used interchangeably in this course.

3. Lipid Classification Triglycerides Most common type of dietary lipid Phospholipids Cell membranes Water and fat soluble Help emulsify fat so it stays dispersed in watery substances like blood. Sterols

4. Triglycerides Glycerol Forms triglyceride “backbone” Three-carbon molecule Three fatty acids Can be of different lengths

5. Triglyceride Functions Energy source During rest and exercise Energy reserve 9 kcal/gram Provides protection Cushioning Insulator (thermal/electrical) Vitamin carrier

6. Fatty Acids Carbon backbone Length varies SCFA (< 6 carbons) MCFA (6 to 10 carbons) LCFA (> 10 carbons)

7. Fatty Acid Saturation Saturated No double bonds Saturated with hydrogen Solid at room temperature Unsaturated Mono and poly Liquid at room temperature

8. Fatty Acid Saturation

9. Omega Fatty Acids Unsaturated Their name is derived from position of first double bond from methyl end Omega 3, 6, 9 fatty acids Omega 3 and 6 are essential fatty acids Linolenic and linoleic acids Form eicosanoids If you would like additional information about omega-3 fatty acids, refer to the article in the extra reading learning folder.

10. Hydrogenation Addition of hydrogen to unsaturated fat Causes formation of trans fats Fats take on saturated properties Raises blood cholesterol levels which is associated with increased risk for heart attack and stroke.

11. Phospholipids Structure Glycerol backbone Two fatty acids + phosphate Sources Egg yokes, soybeans, and peanuts Functions Cell membranes Emulsifiers Transporters

12. Sterols Do not contain fatty acids Have ringed molecular structure Same physical properties as other fats Cholesterol is most common sterol

13. Artificial Fats Carbohydrate derived Oatrim Protein derived Simplesse Specialty fats Olestra (Olean) Salatrim (Benefat) Photo © J. Helgason/ShutterStock, Inc.

14. Fat Intake No RDA or AI 20–35% of total calories ~ 10% polyunsaturated ~ 10% monounsaturated < 10% saturated Avoid trans fats

15. Cholesterol Sources Animals only Components HDL LDL VLDL High levels of LDL increase risk for cardiovascular disease

16. Recommended Cholesterol LevelsYes, even athletes can have elevated cholesterol levels!

17. Guidelines for Lowering Cholesterol Limit saturated fat intake. (Choose oils over solid fat most of the time) Keep daily cholesterol intake < 300 mg. (Choose fats from plant sources like canola and olive oil over animal sources like butter and whole milk) Limit trans fat intake. (Read the ingredient list. If partially hydrogenated oil is listed then the product contains trans fats.) Maintain active lifestyle. Increase fruit and vegetable intake. (Make half your plate fruits and vegetables!)

18. Bioenergetics of Fat Interesting information but I do not expect you to commit it to memory for this course.

22. Benefits questionable;possible gastric upsetRecommendations Avoid fats during exercise Photo © Photos.com

24. Unsaturated fatsCarbohydrates should predominate Consume post-exercise meal ASAP Photo © Photos.com

25. FATS What can you take away from this chapter? What stands out for you? Are there any changes you would like to make to your sports nutrition diet now that you have this new information?