notes/education/nutrition/Energy Balance & Weight Management.md

• An overweight person has extra weight from bones, fat, muscle, body fat, and/or body wader
• Obesity is a condition characterized by excessive and unhealthy bodyfat

Consequences

Obesity

• Type II Diabetes (DM)
• Hypertension
• Cardiovascular disease
• Obstructive sleep apnea
• Osteoarthritis
• Infertility
• Certain cancers
• Gallbladder disease
• Respiratory problems
• Surgical complications
• Clinical depression
• Metabolic syndrome
• Stroke

Underweight

• Fatigue / Anemia
• Nutrient deficiencies
• Lack of energy
• Poor concentration
• Unhealthy hair, skin, nails
• Osteoporosis
• Illness/infection
• Bone fractures
• Amenorrhea
• Infertility
• High risk pregnancy
• Clinical depression
• Low body temperature

BMI

• A numerical value based on the ratio between a person's height and weight that is used to classify a person's weight and measure risk for disease
• Can be calculated using:

 \dfrac{Weight (kg)}{Height (m)^2} or \dfrac{Weight (lbs)}{Height (in)^2} * 703 

Conversions:

• Lbs -> Kg: Divide by 2.2
• Feet -> Inches: Multiply by 12
• Inches -> Meters: Multiply by 2.54 / 100

Ranges

• Underweight: BMI < 18.5
• Healthy weight: BMI 18.5 - 24.9
• Overweight: BMI 25.0 - 29.9
• Obese: BMI >= Obses
  • Obese Class I: BMI 30-34.9
  • Obese Class II: BMI 35-39.9
  • Obese Class III: BMI >=40

Limitations

Not always accurate for:

• Highly muscular individuals
• Older adults
• Chronically ill individuals
• BMI does not take gender, age, race, or activity level into account

NWO

• Normal weight obesity refers to a normal body weight as measured by BMI, but they actually have higher body fat
• Comes with an associated risk of insulin resistance
• Diabetes
• Coronary artery disease

Body Composition and Fat Distribution

• Body composition is the relative and absolute measurement of body tissues, usually expressed as a percent body fat

• Adipose tissue refers to fat cells

• Total body fat refers to to adipose tissue and essential fat

• Essential fat is fat that is vital for survival; found in cell membranes, certain bones, and nervous tissue.

• Subcutaneous is fat accumulation of adipose tissue cells in the tissue under the skin.

  • This layer helps to:
    • Insulate the body against cold temps
    • Protect the body from bumps and bruises

• Visceral fat is the accumulation of adipose cells under the abdominal muscles and over the digestive organs to protect them

• Types of obesity

  • Apple shaped (Central body): Central body obesity: Risk of heart diseases, stroke, diabetes, HTN, cancer. This is more common in men. This is symbolic of extra visceral fat stores
  • Gynoid (Pear shaped): Not associated w/ Chronic Disease Risk

Assessment

• Hydrostatic weight (error of 2-3%)
• Air displacement plethysmography- BODPOD (error of 3-5%)
• Dual energy x-ray absorptiometry: DEXA (Error of 1-4%)
• Bio-electrical impedance (Error: 3-4%) Sends a shock through your body and measures how long it takes. Body fat resists electricity more.
• Skinfold calipers (Error 3-5%)
• Waist circumference -> 35 inches for a women or >40 inches for a man is associated with central adiposity and increased health risk, specifically CVD risk

Health

• Losing as little as 5% of excess body fat
  • Can increase HDL cholesterol levels
  • Reduce high blood pressure
  • Improve glucose tolerance

Energy Exchange

Energy In

• Carbs
• Lipids
• Proteins
• Alcohol

Energy Out (Total Energy Expenditure )

• Basal metabolic rate
  • The minimum number of kcals required to maintain normal body function after fasting and resting for 12 hours. Accounts for ~60-75% of an individual's total energy use
  • Factors that increase BMR include thyroid hormone levels and postexercise recovery
  • Factors that decrease BMR include starvation and aging.
• Physical activity
• Thermic effect of food (digestion, processing, et cetera)
• Non-exercise activity

Ghrelin is a hormone secreted by the stomach that stimulates eating behavior. Grehlin