Dietary Lipids Questions Blackboard PDF

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Dr. Ehlers - questions about the text...

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Dietary Lipids Discussion Activity 1. Is it important to get fat in the diet? Justify your answer. Yes, because… a. Triglycerides serve as an important source of energy at rest and during exercise i. 60-80% of body’s energy needs ii. Predominant energy source for low to moderate exercise intensities b. Fat serves as an abundant energy reserve for the body i. 8-12% body weight in athletic males ii. 18-22% body weight in athletic females iii. Some stored as visceral but most subcutaneously 1. Small amounts in the muscle iv. 80,000-100,000 calories can be stored as fat in a 70kg male in the healthy BF% v. 9 calories/gram & hydrophobic 1. CHO 4 calories/gram and hydrophilic – stored in 3g water c. Visceral and subcutaneous fat provide protection to vital organs and serve as a thermal and electrical insulator in the body i.  buoyancy  drag for swimmers d. Fat plays an important role as carriers of substances into the body and within the bloodstream i. Fat soluble vitamins: A, D, E, K 1. Carotenoids & other phytochemicals 2. Lycopene e. Fats enhance the sensory qualities of foods i. Flavor, odor, texture f. Fat consumption during meals or snacks can enhance satiety level i. Take longer to digest ii. Feel fuller between meals 2. Why is it important to think about the chemical structure of fatty acids?  SCFA (short-chain fatty acids) consist of 2-4 carbons  MCFA 6-10 carbons  LCFA 12+  Shorter chain = more liquid at room temp

 SCFA & MCFA digested & absorbed faster  SCFA rarely found naturally o Except butyric acid – found in milk fat o A by-product of bacterial fermentation of undigested food in the large intestine  Produced from bacteria eating fiber in the colon  Absorbed in colon for energy  Anaerobic fermentation  Fiber 1.5-2 calories/gram  Butyric acid may stimulate colon cells to suppress cancer growth 3. Which of the 4 types of fat (monounsaturated, polyunsaturated, saturated, trans) are considered least healthful? Which are considered most healthful? Provide justification for your answer. The monounsaturated and polyunsaturated fats are more healthful. Unsaturated fats are not solid at room temperature. These have not been associated with cardiovascular disease. Trans fat is the least healthful because it has been shown to cause an increase in blood cholesterol levels. Saturated fats have been associated with coronary artery disease and cardiovascular disease. 4. If you were to advise someone regarding where to find healthy sources of fat, what would you tell them? Plant based substances vs animal 5. What are the proposed benefits of a high fat diet on exercise performance? What does the research say regarding “fat loading” and performance? No research has proven much. May be beneficial towards fat metabolism but lower muscle glycogen stores. 6. What is the significance of cholesterol in the body?   blood cholesterol levels =  risk for cardiovascular disease 7. What advice would you provide to an athlete regarding fat intake before, during and after exercise?

 Preexercise fat to a minimum just enough to sustain satiety for several hours  Not recommended during  Post-exercise: unsaturated fats in small quantities o Asap after competition Case 1: Jenny is an athlete who for the last month has cut virtually all of the fat out of her diet. She states that her reason for this reduction is because her previously high fat intake was “slowing her down” on the track. Now she consumes mostly fat-free foods and her daily intake of fat averages 15-20 grams. Is this level of fat acceptable? Describe the benefits of consuming adequate fat in an athlete’s diet. What changes in dietary intake would you recommend to this athlete? 15g x 9 calories/gram = 135 calories 20g x 9 calories/gram = 180 calories 135 calories / 2000 calories per day = 6.75% 180 calories / 2000 calories per day = 9% Not acceptable. We need to know her body mass. Fat intake is about the same for athletes as non-athletes. How many calories does this athlete need to be healthy and perform at a high intensity? 20-35% ****** goal dietary fat intake Case 2: Shelley has been competing in marathons for many years and she has the very lean stature of an endurance runner. Now, however, she is looking at a new challenge. She and a group of her friends are going to make an attempt at swimming the English Channel. The plan is to train for a year and then make the attempt. She is in excellent cardiovascular shape and her lean build makes cold temperatures tough for her to train in. She is concerned that the cold water of the English Channel will not bode well for her. She currently consumes approximately 3200 kcal/day, about 60% of which is CHO and 20% is fat and protein. What advice would you give her regarding fat intake as she trains over the next year for her swim? Should she take in fat before, during, and after her swim? How many grams of fat is she currently consuming? How many should she consume?

3200 x .2 = 640 kcal 71.11 g of fat she currently is consuming 3200 x .35 = 1120 kcal  35% of daily kcal  124.44 g Recommended: 20-35% 71-124g Fat consumption: Before: During: power bars, carbohydrate fluids, no fat After: replenish CHO, protein for recovery, little fat Increasing her body fat percentage would help her to withstand the cold temperatures better and be more buoyant to help her swimming. How do you increase body fat? -consume more fat  does not need to be biochemically altered before being stored -extra CHO can also be stored but it needs to be biochemically altered - overall caloric intake Case 3: Dave is a 46-year old teacher with a family history of heart disease whose recent blood test reveal high blood LDL cholesterol and triglyceride levels. His doc has advised him to eat less fat in his diet. Dave is a self-confessed “foodie” and although he eats a mostly vegetarian diet he cooks often with butter and cheese. He enjoys wine when dining with friends and limits his intake of fast foods. Although fairly inactive, Dave keeps his weight stable at 170 pounds. He is 5’10” tall. What factors may contribute to Dave’s elevated cholesterol and triglyceride levels? Identify the sources of saturated fat in Dave’s diet. What are some changes he could make to lower his intake of saturated fat from these foods? What general guidance pertaining to the source and firmness of different types of fat would help him identify foods that contained healthier unsaturated fats in his diet? If

Dave decides to use margarine instead of butter, what would you advise him to look for on food labels?  Abdominal adipose tissue Saturated fat intake < 7% Total fat 20% Change saturated to mono and/or poly unsaturated...