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BODY COMPOSITION. Chapters 18 *Your 10 point quiz is the very next slide!!. OVERWEIGHT VS. OVERFAT. Overweight is based on height-weight tables and says nothing about body composition. Overfat actually takes into account the total body composition of lean and fat tissue. FAT DEPOSITS.
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BODY COMPOSITION Chapters 18 *Your 10 point quiz is the very next slide!!
OVERWEIGHT VS. OVERFAT • Overweight is based on height-weight tables and says nothing about body composition. • Overfat actually takes into account the total body composition of lean and fat tissue.
FAT DEPOSITS • Essential fat (around 3%) is needed to live (metabolic functioning, hormone production, insulation, etc.). • Females have additional sex-specific essential fat (9%) for pregnancy and lactation. • Everything else is storage fat (visceral + subcutaneous)
FFM and LBM • Fat free mass is equal to body mass – fat mass. • Lean body mass includes essential fat.
WAYS TO MEASURE • Hydrostatic Weighing • Bod Pod • Skinfolds • Girth measurements • Bioelectrical Impedence Analysis • Dual Energy X-ray Absorptiometry
BODY MASS INDEX • Weight in kilograms divided by height in meters, squared • Overweight is a BMI between 25-29.9 • Obese is a BMI >29.9
WHAT IS OBESE? • Using body fat percentages as an indicator, >20% in males and >30% in females is considered obese. • “Healthy” is typically taught in PED 101 as 10-15% for males, and 18-22% for females.
LOCATION OF FAT • For health reasons, the pattern of fat deposition appears to be important. • Visceral (intra-abdominal) adipose tissue is related to: • Hyperinsulinemia • Insulin resistance/intolerance • Hypertriglyceridemia • Reduced HDL
WAIST TO HIP RATIO • >.8 for women and >.95 in males indicates an increased risk for heart disease.
THEORIES BEHIND OBESITY • The easy one: we eat too much. Calories taken in exceed calories expended. Portion sizes in restaurants have gone up, and television/computer/games have replaced exercise. PE courses are the first to go in K-12.
GENETICS • Genetics may account for 25% of the differences between individuals. • 30% is from cultural transmission. • Leptin (satiety hormone) may be lacking in some (ob gene mutation), plus blunted thermal response to eating and depressed metabolism.
NUMBER OF FAT CELLS • Some people have more fat cells than others. These fat cells always have a minimum amount of fat in them (they never go away unless sucked out) • We add fat cells (hyperplasia) during the last trimester, the first years of life, and the adolescent growth spurt. We can make new fat cells if severely obese. • Usually fat cells just hypertrophy.
SET POINT THEORY • The body tends to want to stay at a level of fatness. • If overfed, it takes time to gain weight through an increased metabolism • If underfed, metabolism is reduced to conserve the fat we have
LOSING FAT • To lose fat, the energy equation must be tipped to insure more calories are being burned than consumed. • The calories being burned come from 3 major sources: • Resting and basal metabolism (70% of calories) • Exercise/activity (20% of calories) • Thermal effect of digestion (10%)
RESTING METABOLISM • Directly related to amount of muscle. • Aerobic exercise influences resting metabolism in that after exercise, the metabolic rate is elevated for up to 5 hours. • Drugs also affect resting metabolism: • Nicotine • Caffeine • Ma Huang (ephedrin)
RESTING METABOLISM • Also affected by climate: warmer weather may increase from 5-20% • Extreme cold may double or triple the metabolic rate.
THERMAL EFFECT OF FOOD • Protein is the highest (up to 25% of food calorie value may be used to digest) • Carbs are next • Fats are last (3% of value to digest and store)
EXERCISE AND FAT LOSS • The total number of calories expended in creating the caloric deficit, not the percentage mixture of macronutrients oxidized, determines the effectiveness of exercise in weight loss.
EXERCISE AND FAT LOSS • Aerobic exercise, where a minimum of 200-400 kcals are expended, is recommended, coupled with a resistance training program to at least maintain the muscle mass already existing. • The longer the better (up to 60 minutes) • Work on volume of exercise (days per week x time exercising)
AEROBIC EXERCISE • Start slow and work up. Time and frequency are more important than intensity. • Stay as active as possible throughout the day (compensation for exercise?) • Look at it as a lifetime behavioral change. • Realize pitfalls and shortcomings
CALORIC RESTRICTION: EATING TO LOSE • Don’t drop calories too far (1200 for men and 1000 for women • Keep carbs high—you’ll keep more muscle, burn more fat, and have the energy to exercise. • Don’t eat within 5 hours of going to bed (light snack is okay) • Don’t deprive yourself—you have to live with this the rest of your life.
GAINING WEIGHT • Resistance training. Positive caloric intake of 2400 calories. • Increase caloric consumption (not the mix of foods—those must remain within the healthy mix of foods); can adjust protein upwards slightly.
Procedures for weight control • Liposuction • Rou-en-Y • Lap band • Jaw Wiring