Energy Balance and Healthy Body Weight

• Being both overweight and underweight present risks to health
• –Overweight: over
• fatness of moderate degree
• BMI 25.0 - 29.9
• –Underweight: too little body fat
• BMI<18.5

• Measurement of weight (in
• lbs.) divided by height (in inches) squared, then multiplied by 703
• -For Example:

Your instructor’s pre-pregnancy weight = 161 lbs, and height 5’9”

163/ (69)2 x 703 = 24.07 (healthy – whew!!)

• 18.5-24.9 heathly
• 25-29.9 overweight
• 30-39.9 obese
• <40 morbidly obese

Doesn’t measure fat %

• Doesn’t work for athletes,
• elderly (shrinking), or pregnant/lactating women

• Can’t measure fat location,
• also a factor

• –Visceral fat – found around the stomach
• (central obesity), more health risk with this

• –Subcutaneous fat – found below the skin, less
• attractive but less health risks

Health costs

• Increase risk of
• stroke, diabetes, some cancers, high blood pressure, heart attack

• Second only to
• tobacco use in causes of preventable death

Social costs

• Ridicule, loss
• of social acceptance

• Inability to
• participate in activities

Financial costs

• Billions spend
• each year treating effects of obesity

• More energy input than
• energy output

Extra calories stored as FAT

• 1 lb of fat =
• about 3,500 calories

• Need to know your Estimated
• Energy Requirements

• Accounts for
• age, height, weight, gender, and physical activity

• Affected by your
• BMR and voluntary activities

Voluntary activities

• Sports, working
• out, things we do extra that require energy

• Over time, these
• things increase our BMR

• Basal Metabolic Rate (BMR) –
• the energy required to sustain life

• Maintaining body
• temperature, functioning systems, etc..

• Affected by
• thyroid, pregnancy, height, gender, etc.

• The more lean muscle, the
• higher your BMR

• Estimated men –
• (lbs) x 2.2 kg x 24 = calories needed/day

• Extimated women – (lbs) x
• 2.2 kg x 22 = calories needed/day

Measure Body Composition by:

• Fat fold test –
• pinches skin under arm /on back

• X-ray absorption
• – measures density

• Underwater test
• – fat less dense than water
• Electrical
• impedance – fat doesn’t conduct electricity well

• Ideal fat %
• Women – 20-30%
• of body mass
• Men – 12-20% of
• body mass

• Stress
• Birth order, genetics
• Increased wealth
• Lower education
• Sedentary lifestyle
• Meal skipping
• Maternal obesity/famine during gestation
• Many, many more – What do
• you think is the biggest factor?

• Ghrelin – released in stomach,
• triggers brain to feel “hunger”

• Endorphins – associated with
• “feeling good” after exercise, can by released in response to other stimuli
• (i.e. smell of apple pie), stimulate “appetite”

• Leptin – triggers that “full”
• feeling, studies show low levels of leptin
• associated with obesity

Satiety- sense of fullness, the state of being satiated

Appetite- the psychological need for food

Hunger- the physiological need for food

• “Diets” don’t work, they are
• short term

• Only life-changing habits
• work

• What happens on a strict
• ”diet”

• Initial rapid
• weight loss due to using glycogen stores and water loss

• Brain start
• using fats for energy, leads to fatigue, headaches, weakness

• Lean muscle can
• be converted into energy, body starts “wasting”, use of proteins increases
• nitrogen waste, hard on kidneys

• Body “thinks”
• it’s a famine, slows down BMR, hold onto foods better, leads to constipation,
• and when you “cheat” the lower BMR causes the yo-yo effect

• Eat small, frequent meals –
• body never goes into “starvation” mode

Balance between carbs, fats, and protein

• Glucose to feed
• the brain

• Fiber for a
• health GI tract

• Fats for
• hormones, padding, etc..

• Proteins for
• enzymes, muscles, etc..

• Exercise, Exercise, Exercise
• – it keeps your BMR up and your heart rate down

• Bulimia nervosa - purge, binge
• Anorexia nervosa - self starvation

eat carb rich meals before big event, max out glycogen stores