Diet and Exercise
Terms
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Energy Balance
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Traditional view.
Stored energy = Energy in - Energy out
Stored energy: Glycogen, fat, body proteins
Energy in: Food alcohol
Energy out: Basal metabolic rate, thermic effect of food, activity (EX and NEAT)
- Changes in energy uptake in past few decades
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Availability of cheap, tasty, energy dense foods
Increased portions
Increased fat intake
Increased refined sugar intake
Decreased fruits, vegetables, and fiber
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Changes in energy expenditure
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Decreased daily living physical activity
Decreased leisure time physical activitity
Increased sedentary behavior
- Disease associations with obesity
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Hypertension, stroke, diabetes, cancer
Gallstones, skin disorders and menstrual irregularities
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Definition of obesity
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Excessive accumulation of body
Males >25% body fat, Females >30% body fat
By BMI >/= 25 overweight, >/= 30 obese
By waist circumfrence, Males > 102 cm (40 in.),
Females > 88 cm (35")
- Is decreased fat intake percentage promising?
- Not really, fat intake remains steady, it's just that Americans are now eating 100 to 300 more calories on average.
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Android fat
- Viseral, central fat that is located in the upper body, which more easily releases FFA with hormonal stimuli. High levels associated with risk of diabetes, hypertension, and hyperlidemia. Typically seen in males.
- Hyperlidemia
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Elevation of lipids in the bloodstream
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Gynoid fat
- AKA gluteofemoral, lower body fat. More resistant to lipolytic stimuli. Generally seen in females, stimulated by estrogen and progesterone, especially during pregnancy.
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Fat hypertrophy and hyperplasia
- Increase in size of size of fat sells and number of fat cells, respectively, in obese individuals. In appears that fat cell size, but not number decreases during weight loss (more research needed).
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Thermic effect of food
- The thermic effect of food, or TEF in shorthand, is the increment in energy expenditure above resting metabolic rate due to the cost of processing food for storage and use. It is one of the components of metabolism.
- NEAT
- Non-exercise thermogenesis. The energy used to heat the body which is not due to exercise.
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Basal metabolic rate
- Basal metabolic rate (BMR) is the amount of energy expended while at rest in a neutrally temperate environment, in the post-absorptive state. The release of energy in this state is sufficient only for the functioning of t
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Fat Balance
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Alternate view from energy balance.
Stored fat = Fat in - fat out
- Criticisms of energy balance
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Energy balance does not account for changes in energy expenditure that come with changes in energy intake and body weight.
Individuals on a high-fat/high-refined carb diet can gain body fat without ingesting excess calories.
Energy balanc
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Factors affecting food choice
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ST3NCH
Social factors, taste, emotion, nutrition, cost, convenience culture, habit
- Problems with dieting
- The energy cost of physical activity decreases proportionally with body mass, but metabolism decreases at a greater proportion due to drops in LBM and RMR. This blunted metabolism makes the diet progressively less effective and slows further weight loss.
- Ketogenic diets
- Diets nearly devoid of carbs and contain 60-70% calories from fat in attempt to increase fat mobilization for energy by a reduction in insulin. This is supposed to create "ketones".
- Criticism of ketogenic diets
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Major concern is for increased risk of disease from long-term use of ketogenic diets. A
Athletes will be unable to try at high intensity without carb stoes.
Amino acids from muscle will be used to try and maintain blood glucose, which
- Important functions of carbohydrates
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Fuel for energy - especially during excercise
Protein sparing - avoid conversion of proteins into glucose for tissue maintenance, repair and growth and keep nitrogen balance.
Fuel for CNS/brain and other tissues
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