Body Composition and Weight Management

State of the Nation

Obesity trends up

first time, life expectancy down

73.6% Americans overweight or obese

Thermodynamics

Cal. density:

1. fat 9 cal per g

2. protein/carbs 4 cal per g

3. alcohol 7 cal per g

RMR: 55-75% (all vital functions)

Exercise: 10-40%

Feeding: 5-15% (digestion)

Body Fat

Stored in adipose cells

men: 3% essential, 12% non

women: 12% essential, 12% non

Nonessential:

1. subcutaneous “below-skin”

2. Visceral “around viscera”

Fat. dist. types:

1. Gynoid: pear-shape, subcutaneous fat (hips and thighs), low risk chronic disease

2. Android: apple-shape, abdomen and visceral fat, higher disease risk

Normal Weight Obesity: low muscle mass high fat mass, but within BMI recommendations (doesn’t appear overweight)

Weight vs Health

Body Mass Index: BMI

<18 under

18.5-25 healthy

25-30 over

>30 obese

Average trends, more risk for causes of low or high weight than the weight itself

IE: smoking or drug use, or fat consumption and sedentary

Blood Regulation

homeostasis between insulin and glucagon ~100mg/dL

insulin lowers Blood Glucose (into cells)

Glucagon raises blood Glucose (from liver)

Diabetes: disorder of B. Glucose levels

1. Type 1: insulin dependent, low insulin production

2. Type 2: insulin independent, low insulin sensitivity

Diabetes symptoms: thirst, frequent urination, fatigue, hunger, weakness, blurry vision, weight loss, numbness in extremities, infections or skin sores

Diabetes decreases adiponectin (hormone coenzyme for insulin reception) (adiponectin is released by adipose cells)

Body Composition Assessments

Height Weight Tables

BMI: weight (kg) / hieght² (m²)

• not accurate for women, children, or very muscley

Abdominal Circumference: estimates visceral fat

• <40” men, <35” women

Bioelectrical impedance:

• highly dependent on hydration

Skinfolds

• men: chest, abdomen, thigh

• women: tricep, hip, thigh

Underwater weighing

Bod Pod

Dual Energy X-Ray Absorptiometry (DEXA)

Set Point Theory: there is an ideal body weight that a body tends to with healthy lifestyle, body will resist change from this value

Diets Do Not Work!

Promoting Health

diet, activity, sleep, relationships, function in school/work, emotionally healthy

Obesity Treatment: Focus on health over weight

Body types are different:

1. mesomorph: muscly

2. ectomorph: tall and thin

3. endomorph: round and heavy

Ideal body weight is one attained through healthy lifestyle

Factors of Obesity and Health

Genetic Predisposition: does not determine fully

Satiety Cues: Appetite vs Hunger, clean-your-plate mentality, don’t trust portion sizes, trust your stomach

Convenience: most likely to eat food when it is convenient

Meal size/frequency: more smaller meals prevents binge eating

Physical Activity: sedentary is bad, “latch-key” syndrome

Childhood Influences: breast-fed, childhood weight, Hyperplasia (low/high cal leads to excess fat storage)

Sugar-Sweetened Beverages: sweet tooth and low satiety

Weight Management Guidelines

Focus on healthful behaviors not numbers

loss of 5-10% of bodyweight for clinical improvements

No more than .5-2lbs loss per week

1lb fat=3500 cals

minimum 1200cal/day women, 1500 cal/day men

Diet and activity together

Strategies for promoting Healthful Habits and Weight Management

Appetite vs Hunger: Hunger is physical, listen to that

Manage Hunger: low Blood Glucose and empty stomach cause it

Eat low calorie density foods, focus on fiber fruits, vegs., water

replace less healthful food with vegs. or fruit

Eat regular, balanced meals: energy released over time

increase variety of fruits and vegs

make healthful choices convenient, and less healthful choices inconvenient

shoot for unsweetened beverages

make vegs half of your plate vegs/fruit, shoot for healthier options for other food

look for in-balance icon at Dining Hall

Eating Disorders

Anorexia Nervosa: self starvation, overexercise, compulsive cal counting: Osteoporosis, iron-def. anemia, fatigue, fainting, heart/brain/muscle atrophy

• Electrolyte imbalance

  • arrythmia (irregular heartbeat)

  • cardiac arrest

  • kidney failure

  • cold intolerance

  • fine-hair growth (Lanugo)

• Amenorrhea: lack of menstration

  • primary: late start

  • secondary: infrequent or nonexistent

Bulimia Nervosa: Binge and Purge: healthy/overweight, erosion of teeth and esophagus, sores on hands from vomiting, Electrolyte imbalance

Binge Eating Disorder: Binge only