Chapter 9. Weight Management Overweight and Underweight. Objectives of Chapter 9. Identify how fat cells develop Identify causes of overweight and obesity Health risks associated with overweight and obesity Aggressive treatments of obesity Weight loss strategies. Fat Cell Development.
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Chapter 9 Weight Management Overweight and Underweight
Objectives of Chapter 9 • Identify how fat cells develop • Identify causes of overweight and obesity • Health risks associated with overweight and obesity • Aggressive treatments of obesity • Weight loss strategies
Fat Cell Development • Hyperplastic obesity • Increase in number of fat cells • Hypertrophic obesity • Increase in size of fat cells • Lipotoxicity • Accumulation of fat in non adipose tissue. For example, heart or liver increase risk of heart failure and fatty liver
Fat Cell Metabolism • Lipoprotein lipase (LPL) • Promotes fat stores • Activity of LPL increase in obese people than lean people • LPL activity is different among male and female • Fat breakdown is slower in women than men • Release of fat in various body parts is different for both sexes • LPL activities increase after weight loss contributing to more weight gain and “set point theory”
Fat Cell Metabolism • “Set point” (your internal thermostat) • theory holds that body opposes weight loss and works to maintain a set weight • Provide an explanation that some inner mechanism seems to set a person’s weight or body composition at a fixed point. • The body readjust after a weight loss to restore that set point.
Prevalence of Obesity Among U.S. Adults (BMI > 30) • 1991: Only 4 states had obesity rates greater than 15% • 1995: Over ½ of the states had obesity rates greater than 15% • 2000: Only 1 state had an obesity rate below 15%, most had obesity rates greater than 20%, and one had obesity rate greater than 25% • 2005: All states have at least 15% obesity rate, only 4 states has obesity rate < 20%, 1/3rd of the states have obesity rate > 25%, 3 states have rates > 30% U.S. Obesity Trends 1985–2006 Adapted from: www.cdc.nccdphp/dnpa/obesity/trend/maps/index.htm
Overweight • Overweight (BMI 25-29.9) and obesity (≥ 30) are widespread health problems that are continuing to increase. • Many refer to overweight and obesity as an epidemic. • For good health, weight management is important.
Health Risks of Overweight Diabetes Hypertension Cardiovascular disease Sleep apnea Osteoarthritis (bone disease) Some cancers Gallbladder disease Kidney disease Respiratory problems Complications in pregnancy and surgery Body Weight, Body Composition, and Health
What Factors Are Likely to Affect Body Weight? What and how often you eat, Hunger and appetite affect what you eat. Appetite is psychological desire for food Hunger is physiological need for food, subsides as feeling of satiation sets in Satiety determines length of time between eating episodes environment
What Factors Are Likely to Affect Body Weight? Physiological feedback mechanisms involving mouth, stomach, intestines, and brain increase or decrease hunger Many hormones play role: Ghrelin: produced in stomach increases hunger and appetite positive energy balance High in obese people as well as people with eating disorder Leptin: in fat tissue signals brain to decrease hunger and food intake. Promote negative energy balance May be deficient or defective in obese individuals, but very rare Cholecystokinin:released when stomach is distended, increasing feelings of satiation, decreasing hunger
What Factors Are Likely to Affect Body Weight? Genetics play a role in determining body weight Risk of becoming obese doubles if parents are overweight, triples if obese, five times greater if severely obese Genetic differences in level or function of hormones, such as high ghrelin or low leptin levels, increase obesity. Many obese have adequate leptin but brain has developed resistance to it
What Factors Are Likely to Affect Body Weight? Environmental factors can increase appetite and decrease physical activity. cheap and easily obtainable energy-dense foods stimulate appetite We work more and cook less. About 1/3 calories come from ready-to-eat foods prepared outside of home Frequent dining out associated with higher BMI Inadequate physical activities Americans eating about 300 calories/day more than in 1985
What Is a Reasonable Rate of Weight Loss? National Institutes of Health: overweight individuals should aim to lose about 10% of body weight over 6-month period Example: 180-lb person should lose 18 pounds/6 months = 3 lbs/month, ¾ lb/week To lose 1 lb of body fat, need 3,500 calorie deficit Weight loss of ½-1 lb/week, need to decrease daily calories by 250-500 calories Diet Meals videoOverweight Childrenapproach to weight loss
How Can You Lose Weight Healthfully? Successful long-term weight loss requires changes in three areas: diet, physical activity, and behavior Eat smart, because calories count: add satiation to low- calorie meals by including higher-volume foods Eat more vegetables, fruit, and fiber Include some protein and fat in your meals Protein increases satiety most Fat slows movement of food from stomach into intestines Choose lean meat, skinless chicken, fish, nuts, and unsaturated oils.
Add high-volume fruits and vegetables to displace higher calorie foods.
How Can You Lose Weight Healthfully? Use MyPyramid as a weight-loss guide: High volume of fruits, vegetables, whole grains, some lean protein, modest amounts of fat Diet should contain variety of foods from all food groups Replace higher-calorie foods with lower-calorie options from each food group. Example: replace full-fat dairy with nonfat products Replace sodas with water
How Can You Lose Weight Healthfully? Move to lose 60 minutes/day of moderate-intensity activities can prevent becoming overweight and aid in weight loss 10,000 steps/day can reduce risk of becoming overweight Spot Reducing Regular aerobic exercise and weight loss will help trouble spots. Strength training can improve muscle tone. Stretching can help flexibility Exercise may help to curb appetite. Activity can reduce stress and improve self-esteem Break bad habits Behavior modification: change behaviors that contribute to weight gain or impede weight loss
Fad Diets Are the Latest Fad Research shows that reduction of calories, not the composition of the diet, is effective in weight loss. People who adhere the longest to weight-loss diets lose the most weight. High drop-out rates for most extreme diets (Atkins and Ornish diets) Beware of fad diet sensational claims and hype: “It’s the carbs, not calories, that make you fat!” Celebrity-endorsed miracle weight-loss products “Natural” substances help lose weight without risk How to get fat without really trying
How Can You Maintain Weight Loss? Weight cycling is a common result of fad diets. Weight loss can be maintained if keep healthy habits used during weight loss New, lower weight requires less calories to maintain weight Physical activity can close the “energy gap”, easier than further reducing caloric intake 60-90 minutes/day of moderate-intensity physical activity recommended to maintain weight loss
Aggressive Treatments of Obesity • bariatric surgery – Gastric bypass and gastric banding • Results in dramatic weight loss and reduction of hypertension, diabetes, high blood cholesterol, and sleep apnea • Risks include ulcers, gallstone, bleeding in stomach and intestines • for individuals with clinically severe obesity and major medical problems. • Changing and improving eating and exercise habits offer the greatest benefit.
Aggressive Treatments of Obesity bariatric surgery • Over 100,000 is performed annually and numbers continue to grow • Limit food intake by reducing the capacity of the stomach • To qualify, a person must be at least 100lbs over their ideal body weight or BMI > 40 • Must comply with prescribed diet • At risk of iron, b12, folate, calcium and vit D deficiencies • Infections, nausea, vomiting, and dehydration is a very real possibility after surgery • Lifelong medical supervision is necessary
Aggressive Treatments of Obesity • Drugs • Sibutramine (meridia) suppresses the appetite and is most effective when used with a reduced kcalorie diet and increased physical activity. There are many side effects. • Orlistat (Xenical) blocks fat digestion and absorption. There are many side effects. You can now get a low dose over the counter under the brand name, Alli. • Other drugs are still under study • Liposuction is a popular procedure that is primarily cosmetic but poses risk. Provides no health benefit
How Much Should you Weigh? Ideal Body Weight (IBW) • Men • 106 pound for the first 5 feet, + 6 pounds for every inch over 5 feet. For example, a man who is 6’1” have IBW of 184 pounds • Women • 100 pound for the fist 5 feet, + 5 pounds for every inch over 5 feet. For example, a woman who is 4’11” have IBW of 95 pounds
Extra Credit • 10 points • Use worksheet for chapter 9 to evaluate a poplar weight loss program • Must be typed • No more than 1 page • One word answer will not be accepted