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42 Cards in this Set
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- Back
- 3rd side (hint)
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Leptin |
- body weight regulating hormonal substance that's produced by fat and released into the blood stream and acts on hypothalamus - linked to mutant gene that causes human obesity - affects how much one eats, how much energy one expends, and ultimately how much one weighs - causes blunt urge to eat when caloric intake maintains ideal fat stores because brain inadequately assesses the body's adipose tissue status --> continuing the urge to eat |
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National epidemic contributing factors for obesity |
1. Genetics 2. Increased caloric intake of saturated fats 3. Decreased physical activity levels |
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Adipocytes |
- "fat cells" |
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How does adipose tissue mass increase? |
1. Fat cell hypertrophy (growth) 2. Fat cell hyperplasia |
2 ways |
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Effect of weight loss on adipocyte cells |
1. Decrease in adipocyte size 2. No change in number - in adults, the major change in adipose cellularity in weight loss is shrinkage of the adipose sites |
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Principles of weight control: energy balance |
- our body mass remains constant in this equation when the caloric intake of food equals our total caloric expenditure |
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Weight loss with the energy balance equation |
1. Reduce caloric intake below daily energy requirements 2. Maintain normal caloric intake and increase energy expenditure through additional physical activity above daily energy requirements 3. Decrease daily caloric intake and increase daily expenditure |
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Diet for weight control |
- reduces daily caloric intake by 500 - 1000 kilocalories per day - make good food choices: 1. Complex low- glycemic index CHOs 2. High vitamin, mineral and phytochemical food 3. Low energy density (low fat food) 4. Low saturated fat foods |
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Set point theory |
- all persons fat or thin have a well regulated internal control mechanism located deep within the lateral hypothalamus that maintains with relative ease a preset level of body weight and or body fat with limited range. - basically states that physical activity may lower a person's set point where diet has no effect |
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What does exercising for weight control do? |
1. Increases energy output 2. Increases lean body mass, while decreasing fat mass - Start slowly and progress gradually - select the appropriate mode of exercise to match individual goals |
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The ideal combination: diet and exercise |
- offers more flexibility to achieve negative calorie balance - offers both weight loss and health benefits - facilitates longer maintenance of weight |
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What is a healthy diet? |
- emphasizes fruits, vegetables, whole grains, and fat free/low fat milk - includes lean meats, poultry, fish, beans, eggs, and nuts - is low in saturated fats, Trans fats, cholesterol, and sugar |
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Link between diet and disease |
High rates of cancer: high fat diets, fiber, alcohol Low rates of cancer: fruits and vegetables |
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ACSM recommendation for exercise |
Activity: anything using large muscle groups that can be maintained continuously and aerobically Intensity: 55 or 65 - 95% max heart rate (varies by type of activity) Training duration: 20-60 minutes Frequency: 3-5 times per week Flexibility: stretches all major muscle groups, 2-3 days per week, 10-30 seconds Muscular strength: 1 set of 8-10 exercises, 2-3 days per week, 8-12 repetitions |
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Carbohydrate in terms of energy |
- preferred energy substrate for brain and central nervous system - provide the substrate glucose when necessary - maintains blood glucose homeostasis - prevents fatigue - necessary to maintain work above 50% VO2 max |
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Monosaccharides |
- are the basic unit of a carb - ex: fructose, glucose, galactose |
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Disaccharides |
- type of oligosaccharide - form when 2 monosaccharides combine - ex: Glucose + fructose = sucrose Glucose + galactose = lactose Glucose + glucose = Maltose |
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Polysaccharides |
- linkage of 3 or more sugar molecules - starch and fiber are common plant polysaccharides |
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Starch |
- storage form of carbs in plants - can be found in seeds, corn, cereal, pasta, and various grains of bread |
Plant polysaccharides |
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Fiber |
- non-starch - polysaccharide that includes cellulose and is the most abundant organic molecule on earth - can be found in leaves, stems, roots, seeds, and fruit coverings |
Plant polysaccharides |
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Carbs are classified according to |
1. Type of CHO in food 2. Blood glucose response to CHO 3. Complex vs simple |
3 things |
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Glycemic index |
- all carb containing food does not digest and absorb at similar rates - index is a system that ranks food on on a scale of 1-100 based on their effect on blood sugar levels - reflects glucose in systemic circulation and uptake by peripheral tissue |
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Glycemic index: breakdown of foods |
High - produce a large and rapid rise in blood glucose and insulin - greater increase in muscle glycogen stores - ex: cake, ice cream, white rice, carrots, bananas Moderate: - brown rice, pastry, popcorn, potato chips, oatmeal, sweet potato Low: - plums, fructose, apples, lentils, peanuts |
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Fuel tanks of High Intensity Exercise |
- muscle glycogen accounts for largest reserve (300-400g glycogen) - blood glucose has least amount of storage (only about 2-3g) - liver glycogen stores 2nd most (80-90g of glycogen ) - each gram of glycogen = 4 calories of energy |
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Glycogen |
- storage carb within the mammalian muscle and liver - it's a large polysaccharide - each gram contains 4 calories of energy |
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Carbohydrate use during exercise |
- initially, 1/2 of energy is derived from carbs and fats - as muscle glycogen declines over time through exercise, our blood glucose becomes important source of carb energy for muscle |
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Variables affecting carb use during exercise |
1. Duration 2. Intensity 3. Physical fitness level 4. Environment 5. Nutritional status |
5 things |
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Initial glycogen stores |
- muscle glycogen provides energy without oxygen - contributes considerable energy in the early minutes of exercise when oxygen use fails to meet oxygen demands - muscle glycogen is what we're tapping into when we first begin exercise |
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When does fatigue occur? |
- occurs when physical activity continues to the point that compromises the liver and muscle glycogen content despite sufficient oxygen availability to the muscle and almost unlined energy supply from our stored fat. - regardless of how much oxygen we have, fatigue will happen if exercise is going on for a long time. - so diet is going to affect our glycogen reserves and exercise performance |
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Insulin: influence of CHO |
- beta cells of pancreas (glucose uptake) release dependant upon intensity 1. Light: gradual decrease in levels 2. Moderate: steeper drop over time 3. Heavy: immediate decrease |
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Glucagon: influence on CHO |
- alpha cells of pancreas (glucose release) dependent upon intensity as well 1. Light: no rise in levels seen until about 2 hours of exercise 2. Moderate: stimulated after about an hour 3. Heavy : no change |
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Norepinephrine: influence on CHO |
1. Light: gradual rise in release 2. Moderate: stimulated release approximately 30 minutes post onset of exercise 3. Heavy: immediately released |
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Epinephrine: influence on CHO |
- key stimulant of muscle glycogen breakdown 1. Light: gradual increase right away until about 2 hours and then large increase 2. Moderate: steeper increase in concentrations after 60 min 3. Heavy: immediate release |
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Cortisol: influence on CHO |
- is a stress hormone, steroid hormone in adrenal cortex - increases blood sugar - primary stimulator of gluconeogenesis, especially during high intensity - increases availability of amino acids for conversion to glucose |
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Fiber type and CHO use |
1. Light intensity : slow twitch fibers, using some glycogen not FG or FOG 2. Moderate intensity: slow twitch fibers used but stimulates increased glycogen use and activation of FOG and FG fibers occurs faster 3. High intensity: fast twitch fibers used as majority and deplete before 60 min of exercise is done. The FOG is used heavily but also heavily depleted and slow twitch fibers are not used at all |
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CHO intake prior to exercise |
- pre-competition meals recommended 2-6 hours prior to exercise - if palatable liquid or solid, 1 hour prior to exercise - recommended to consume low GI foods to eliminate the insulin surge and promote slow release of glucose |
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Reasons for feeding during exercise |
1. Spares muscle and liver glycogen (prevents it from depleting) 2. Prevents hypoglycemia 3. Reduces fatigue by 33% 4. Performance time improves overall |
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Gender differences in carb loading |
- greater fat free mass in males to store glycogen - estrogen may not favor glycogen utilization - males have high calorie intake compared to women - CHO loading may not work in women |
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Fats overall |
Substances that are insoluble in water - affect absorption and digestion - soluble in organic solvents like Ester or acetone - benefit: make our food taste better |
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Simple lipids |
Neutral fats that consist primarily of triglycerides |
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Saturated fatty acid |
Contain only 1 covalent bond and get broken into animal or plant saturated fats |
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Unsaturated fats |
Contain 1 or more double bond and are considered unsaturated with their respective to their hydrogen ion |
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