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:HyperinsulinemiaInsulin resistance/intoleranceHypertriglyceridemiaReduced 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 metabolismIf 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