10 13 08 Unit 9 Obesity to Underweight Key Concepts and Facts Ideal weight and shape are defined by culture and health measures but should be based on health alone Rates of overweight and obesity are increasing worldwide Diseases and disorders related to overweight and obesity are also increasing Location of fat stores and the amount of body fat are important to health Causes of obesity are complex but relate to diet physical activity environment and genetics Underweight in the U S usually results from genetics or from poverty illness or voluntary restriction of food intake Obesity Habits Die Hard Feast and Famine lifestyle encouraged eating regardless of what was available In Western civilization where food security is good overeating leads to obesity Food Security all the nutrients we need The Hamwi Method Healthy weights in women are First 5 feet of height 100 lbs Each additional inch of height 5 lbs Healthy weights in men are First 5 feet of height 106 lbs Each additional inch of height 6 lbs Body Mass Index BMI Tables are based on Body mass in kg height in meters squared See Illustration 9 2 Example 120 lbs and 5 5 BMI 20 18 5 Underweight 25 29 9 Overweight 30 or more Obese Normal is 18 5 24 9 If you are in the Normal BMI Range Weight losses of 9 lbs or more are usually considered unhealthy unless a person is above their healthy range Insert Friday Notes Here 10 20 08 Something to Think About BMI doesn t always work to measure obesity Some people with lots of lean body mass can fool the BMI into classifying them as obese Methods for Measuring Body Fat Skin fold thickness a measurement of a skin fold thickness that lies beneath the skin Bioelectrical impedance measurements Underwater weighing the less the person weighs underwater compared to dry land they will have a higher percent body fat Expensive Magnetic resonance imaging MRI where fat is a poor conductor of electricity but water and muscles are good conductors They are measuring a electrical current that goes from the ankle to the wrists Very expensive Hydration plays a huge part Body fat and muscle mass are photographed Obesity or Obesities Number and size of Fat Cells An unproven theory Set point theory Unproven theory Genetics Accounts for 25 40 incidence requires an environmental trigger Obese children become obese adults Weak for obese infants and children under 3 years strong for children between 10 and 14 those have at least one obese parent High fat diets a diet of over 34 Calories from fat will encourage obesity compared to a diet of under 28 Calories from fat Low physical activity A definite correlate Bottom Line Don t let your kids get too overweight during 10 14 and keep them active At college ages major weight gains are likely between 25 and 34 years of age Exercise regularly even if it s a daily walk Underweight People Underweight Defined less than 20 body fat adult females or less than 12 body fat adult males Underdeveloped nations Poverty food insecurity Developed Nations HIV AIDS Pneumonia Cancer Anorexia Bulimia Poverty Middle Class Malnutrition Some parents feed their children low fat low Calories diets to prevent obesity During growth years this is a mistake Also Life expectancy in overweight obese adults 3 to 6 years shorter than average Death and disease rates are also higher for underweight people Low body fat levels can cause Delayed physical maturation during adolescence Infertility Accelerated bone loss Problems that accompany starvation End of Chapter 9
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