Energy balance and obesity

• Changes over time with height and weight in men and women


  weight has gone up a lot and height has gone up slightly.

  
  

  men: 1960- 68 in, 165 lbs. 2012- 69 in, 195 lbs.

  
  

  women: 1960- 53 in, 140 lbs. 2012- 54 in, 165 lbs.
• obesity trends in regions of the US


  south always has the highest obesity rate and west is lowest, generally

  
• causes of death in the US

  365,000 (15%) from poor diet and inactivity

  435,000 from smoking but smoking deaths are on the decline
• obesity


  excess accumulation of body fat/adipose tissue.- there are challenges of measuring body composition
• body composition


  proportions of muscle, bones, fat, and other tissues that make up a person's body weight.

  
  

  found using skin fold analysis, dexa machine, bioelectric impedance device.

  - important to look at fat mass vs. fat free mass
• cut points for excess body fat

  men: >22% body fat.

  - 25% in men over age 40.

  women:>32% body fat.

  - 35% in women over age 40.
• evaluating risks from body fatness


  1. body mass index (used as a screening device)

  2. waist circumference

  3. disease risk profile
• BMI and its limitations


  describes relative weight for height.

  - (weight/in^2) *703

  
  

  limitations: not a direct measure of body composition & fails to show location of excess fat.

  - not useful in pregnant women, athletes, adults over 65.

  - may falsely identify obesity in certain ethnic or racial groups
• BMI indexes of obesity

  underweight:<18.5

  normal weight 18.5-24.9

  overweight: 25-2-9.9

  obese:>30

  
  

  71% of population is overweight or obese and 42% of population is obese
• measuring waist circumference cut points


  men:>40 inches

  women:>35 inches
• visceral fat


  central fat is associated with visceral fat which is fat deep within the abdomen.

  - visceral fat contains adipokines

  
• subcutaneous fat


  fat that is underneath the skin and has benefits to cushion and insulate
• adipokines


  protein hormones made and released by adipose tissue cells that regulate inflammatory processes & energy metabolism in tissues.

  - central obesity causes a shift in balance of adipokines which results in increased inflammation and insulin resistance

  - CVD is an inflammatory disease in insulin resistance and can lead to a risk of diabetes
• disease risks (comorbid conditions) associated with obesity


  prediabetes and type 2 diabetes, hypertension, heart disease, certain types of cancer.

  - heart disease leads to dyslipidemia which is abnormal blood lipids (low HDL, high triglycerides
• why treat obesity?


  comorbid conditions that are made worse by obesity are the biggest killers in the US, small weight loss can have a major effect on health risks, decreased societal cost with adequate prevention and treatment
• etiological factors


  physiological, genetic heredity, lifestyle choice, diet and activity, social influences, governmental or societal forces, environmental cues

  
• estimated energy requirements


  established by DRI committee and based on sex, age, physical activity, height and weight
• weight management energy in controls

  1. hunger and appetite; hunger is a physiological need and appetite is learned motivation

  2. seek food and start eating

  3. keep eating

  4. satiation: the perception of fullness that builds throughout the meal. protein and fiber affect satiation

  5. satiety: a feeling of fullness that lingers after a meal. fat and fiber increases satiety

  
• weight management energy out controls

  estimated energy expenditure

  
  

  50-65% resting metabolic rate (affected by age, body composition, height, growth, stress, fasting, thyroxine).

  
  

  5-10% thermic effect of food: the amount of calories that requires to digest and absorb the amount of calories we are consuming

  
  

  25-50% physical activity

  
• factors that affect BMR

  age, height, growth, body composition, fever, stress, environmental temperature, fasting/malnutrition, thyroxine
• lifestyle strategies


  1. dietary patterns

  2. physical activity

  3. behavior modification
• eating habits


  eat regularly, increase fiber, adequate protein, consume consistent meals with macronutrient balance in meals, choose nutrient dense foods
• physical activity to improve health

  improves: cardiovascular function, dyslipidemia, HDL cholesterol levels

  lowers: blood pressure, mortality rate
• health benefits of weight loss

  decreases: cardiovascular risk, glucose and insulin levels, blood pressure, LDL and triglycerides (increase HDL), severity of sleep apnea, symptoms of degenerative joint disease
• essential treatments of obesity

  dietary patterns, physical activity, behavior modification, social and environmental support.

  
  

  goal weight in treatment of obesity 5-10% weight loss that can be maintained for 6 months
• behavior modification for healthy weight

  build social support with positive relations and focus on non-weight outcomes