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 Development

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%

Adapted from: www.cdc.nccdphp/dnpa/obesity/trend/maps/index.htm

U.S. Obesity Trends 1985–2006

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.

Body Weight, Body Composition, and Health

• 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

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 video Overweight Children approach

to weight loss

Three Pieces of the Long-Term Weight Loss Puzzle

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.

The Energy Density of Foods

Add high-volume fruits and vegetables to displace higher

calorie foods.

The Volume of Food You Eat

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

What’s in the Fad Diets?

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

Gastric bypass surgery video

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