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24 Cards in this Set
- Front
- Back
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Body Composition
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The partitioning of body mass into fat-free mass (weight or percentage) and fat mass (weight or percentage)
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Two-component model of body composition:
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Fat mass
–Essential and non-essential Fat-free mass –anything NOT fat mass –bone, muscle, organs, connective tissue |
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Densitometry
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Measures body density by MEASURING body volume
–Body Density = body mass/body volume –Volume = land weight –water weight –% body fat = (495/body density) –450 (Siri) –+2 % error |
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Skinfolds
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The double thickness of skin plus the adipose tissue between the parallel layers of skin
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Bioelectrical impedance
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–Based on electrical conduction through the tissues
•Fat free mass has high water content –High conductivity •Fat mass has low water content –High impedance to flow –Impedance to current flow is used to calculate (estimate) % body fat –+3-5 % error if performed perfectly, |
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BMI
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•18.5 –24.9 = normal
•25.0 –29.9 = overweight •> 30.0 = obesityCopyright |
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Height/Weight Charts
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Developed on a limited population
–Lowest mortality (would not include those with existing disease) life insurance policyholders, age 25-59 •Self-reported at time of policy purchase •Weight provides no information regarding relative body fat, which is the real health risk |
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Adipocytes (fat cells) –stored TGs
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–Adipocyte Hypertrophy
–Adipocyte Hyperplasia –30-50 billion cells in normal weight –75-80 billion cells in obese –Once there, fat cells do not naturally go away |
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DistributionOverweight and Obesity
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Waist-to-hip ratio –estimates fat distribution
•High values increase risk –> .9 males, > .8 females •Waist Circumference –> 40 inches (males) > 35 inches (females) |
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Health Risks of Overweight and Obesity
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1. Cardiovascular disease
2. Hypertension (high blood pressure) 3. Gallbladder disease andHypercholesterolemia (high cholesterol) 4. Diabetes mellitus 5. Cancer 6. Miscellaneous disorders |
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Kilocalorie
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The amount of heat needed to raise the temperature of 1 kg of water 1 degree Celsius
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Caloric Balance Equation
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The mathematical summation of the caloric intake (+) and energy expenditure (-) from all sourcesThe
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Caloric Balance =
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+ food ingested (kcal)
-basal or resting metabolic rate (kcal) -thermogenesis (kcal) -work or exercise metabolism (kcal) -energy excreted in waste products (kcal) |
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Impact of exercise and exercise training on food intake
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-No clear evidence for atransient reduction or increase in food intake following exercise bout
-Active individuals consume more calories than sedentary individuals -energy intake increases (highly trained and lean) or remains unchanged as a result of training (untrained and obese) -when training ceases, energy intake is spontaneously reduced, but usually not matched to reduction in EE |
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Basal Metabolic Rate-
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The level of energy required to sustain the body’s vital functions in the waking state, when the individual is in a fasted condition, at normal body and room temperature, and without psychological stress
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Resting Metabolic Rate
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the energy expended while an individual is resting quietly in a supine position
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The Impact of diet on resting metabolic rate
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Severe caloric restrictiondecreases RMR
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The impact of a single exercise bout on resting metabolic rate
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Transient increase -EPOC
-A lot of speculation, but little clear evidence that an exercise bout changes RMR |
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Exercise training and resting metabolic rate
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Research is inconclusive
-RMR is related to muscle mass |
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Weight cycling
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Repeated bouts of weight loss and gain
Does not appear to negatively influence RMR or subsequent weight loss |
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Dieting alone is ineffective
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–total body weight and fat mass will likely decrease
–fat-free mass will also decrease –maintenance is unlikely |
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Exercise alone may be more effective
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Time-consuming: You would have to run 35 miles to expend the energy in one pound of fat
•900 cal/week for 1 year = 13.5 lbs •1200 cal/week for 1 year = 18 lbs. •greater fat mass losses + gains in FFM |
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Diet + Exercise
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seems to be the most effective method to promote long-term fat loss, in addition to gains in fat-free mass
•Maintenance of weight loss is much better in those who exercise |
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Recommendations
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-Diet plus exercise is recommended-Goal is caloric deficit of 3500 -7000 kcal per week (500 -1000 per day) in order to lose 1-2 lb per week
-250 –500 kcal in caloric restriction/day -250-500 kcal in exercise expenditure/day |
