OBESITY

We are in an obesity epidemic

• Estimates: American adults

2/3’s overweight

1/3 obese

• Average American man (20-74): weighs 191 pounds

• Average American woman: 164.3

• 2007 data: 24% since 1960’s

BMI

Americans World average

Male 28.4 24.4

Female 28.8 25.3

Children & teens also becoming overweight

Harvard study 2006: Even babies becoming fatter

Children born heavy

Gain weight quickly- early in life

Massachusetts: sharp obesity & diabetes: similar- national trends

Relationship to education level

Obesity Increase by state: 1991- 2002

1991

2002

But: 2007- Leanest states:

#1 Colorado; #2 Massachusetts

Obesity: immigrants to US

• Asian- American children (China, Korea, Japan): Queens, N.Y.

• Risk obesity & diabetes

Why weight gain?

• Low cost fast foods

• Convenience

• Super-sized portions

• Calorically dense

foods

Fast food row: Queens, NY Flushing section: main street

Cluster- fast-food/pizza restaurants

Obesity growing: worldwide

Canada

Europe

Asia

South America

What is overweight? Obesity?

• Overweight: 10-19% above healthy weight standard

BMI: 25-29.9

• Obesity: 20% or more above healthy weight

BMI: 30 or greater

Obesity linked to 5 out of 9 causes death in US

Increased Health Risks

1. Cardiovascular disease

2. High blood pressure

3. Osteoarthritis: some hospitals- 50-66% patients- joint replacement surgery- overweight/obese

Increased Health Risks

4. Surgical complications

5. Poor wound healing

6. More difficult to exercise

7. Type 2 diabetes

8. Fasting glucose

9. Gallstones

10. Respiratory disease (worsens asthma)

Increased Health Risks

11. Triglycerides

12. LDL

13. HDL

14. Menstrual irregularities

15. Overweight girls- age 3: more likely- start puberty by 4th grade

Increased Health Risks

16. Nonalcoholic fatty liver- “silent liver disease”- liver clogged with fat

Fatty liver: associated with “metabolic syndrome”

• Obesity- especially waist • High blood pressure • Triglyceride • HDL • Insulin resistance • Type 2 diabetes • Heart disease • Stroke

Increased Health Risks

17. Cancer

Men: colon, rectum, prostate

Women: uterus, cervix, ovary, breast, gallbladder, colon

“Obesity-

makes ovarian

cancer deadlier”

Weight & cancer risk: women

Weight & cancer risk: men

Increased Health Risks

18. Sleep apnea: breathing passages temporarily close

Sleeper stops breathing

Suffocating level O2 –nightly

Wake up: 500 times- gasping-air Increased risk- heart disease

Snoring common Daytime: chronically tired

Sleep apnea: football players

• Texas State University

• 6/15 players tested: sleep apnea

• Related to body weight: 21 players 250 pounds, 7 weigh 300 pounds or more

• NFL lineman: body weight + large necks: 1/3 have sleep apnea

Obesity: the good news

• Losing 10% weight: goal over 6 month period

• Many Health Benefits

Decreases:

Blood pressure, cardiovascular disease risk, stroke risk, blood cholesterol, triglyceride, blood glucose, diabetes risk, osteoarthritis, stress on joints (hips, knees, spine), cancer risk, sleep apnea

Benefits: increased

• Self-esteem

• Well-being

• Appearance

Concern: Yo-Yo Dieting

1. Repeated cycles: weight loss, regain

2. Body fat with each regain

3. BMR- more difficult- future weight loss

But…. you need some body fat

• Energy- storage calories- future use

• Warmth/insulation

• Cushions organs

• Menstrual cycle- women

Women store more fat than men. Why?

• Menstrual cycle: ~ 12 years • Girls (puberty): menarche • Menarche: critical level of body fat

needed • Body fat and fat/lean ratio important: ovulation, menstruation, sustain

pregnancy & fetus (+300 calories/day), lactation (+500 calories/day)

Amenorrhea: no menstrual cycle

• Malnourished young girls

• Ballet dancers/runners

• Anorexia nervosa

• Change fat/lean ratio sex hormones amenorrhea

• Regain weight: start menstruation

Adipocytes: store fat

Adipocytes: number & size

• Fat cells in number (normally):

1. Infants

2. Adolescence (14 boys, 12 girls)

3. Pregnancy

Adipocytes

• With modest weight gain: size

• With significant gain: size & number

• Obese person: 600 billion fat cells

• Normal weight: 300 billion

• Obese fat cell: 20% more fat/cell

With weight loss

• Decrease in fat cell size

• No change in number

• Problem: obese person loses weight: no loss fat cells

• Always ready: gobble up/store fat

• Rats: near starvation: fat cells shrink but same number

What controls when & how much you eat? Hunger, satiety, appetite

• Hunger: innate, physiological “drive” to eat

• Growling stomach, light-headedness

• Blood glucose

• Affects cells: hypothalamus

Hypothalamus

• You eat food

• Stomach & intestine nerves detect: volume

• Impulses: other cells in hypothalamus: satiety:

feeling of fullness,

satisfaction

• You stop eating

Earlier studies: discovered “pleasure centers in the brain”

• Implant needle electrode: rat brain

• Mild shock to brain

• Allow animals: do it yourself “self stimulation”

• Some rats stimulated brains: >2000 times/hr, 24 hrs straight

• “Reward system” of brain in hypothalamus & midbrain

• Hypothesis: exciting neurons associated- basic drives: hunger, sex, thirst

• Hunger- inborn

• Appetite- can be experienced in absence of hunger

• Examples: sight, smell foods, mood: depressed/happiness, going to movie (time to eat), watching football- TV

• Appetite: may lead to overeating

Leptin & weight regulation

• Leptin: protein hormone produced by adipocytes

• Discovered in mice: Dr. Jeffrey Friedman

• Great hopes: “cure for obesity”

• Amgen (biotech): $25 million for commercial rights

• fat cell size leptin produced

• Leptin blood hypothalamus (receptors)

• In mice: energy expenditure

food intake

weight gain

If fat cells shrink

Leptin from fat cells brain

Signals:

energy expenditure

food intake

Leptin: like a thermostat for fat

• Regulates amount of fat (lipid) in adipocytes

• Called “lipostat”

Leptin important: obese strain of mice

Obese mice: 3X normal weight mice

• Single defective “leptin” gene

• Not producing leptin

• Overeat, energy expenditure, extreme obesity

Leptin therapy

• Both have defective leptin gene

• Mouse on right: leptin injections, control weight

Humans: have leptin gene

• But human obesity not caused by single gene

• Many “obesity” genes interacting with environment

• Inject obese people- leptin

• Not much success

• Obesity- more complex in humans

Are there physiological differences between obese & non-obese people?

• Yes

• Classic experiment by Dr. Jules Hirsch 1959

• Studied people-

obese from

childhood or teens

• 8 months- Rockefeller University

• Controlled environment

• Given: 600 calories/day- liquid diet

• Lost on average: 100 pounds

• Fat cells shrunk to normal size

• Outward appearance: looked like person who was never fat

• Went home- motivated- stay thin

• But… all regained weight

What happened? Were these people somehow “different”?

• Before diet: obese people: metabolism same as normal weight people:

# calories burned/(meter)2 body surface

During weight loss

• Metabolism slowed

• Burned 24% less calories

• Also had: “semi-starvation neurosis”

• Dream/fantasize- food

• Thought about- breaking diet

• Anxious, depressed

• Some suicidal

• Bottom line:

These obese people had physical & psychological signs: starvation

Resembled: “starved” non-obese people

Another study: Dr. Ethan Sims UVM

• Make thin people fat by overfeeding

• State prisoners (volunteers)

• 4-6 months

• 20-25% weight

• Some ate: 10,000 calories/day

• Once men became fat:

50% metabolism

• Rapid metabolism: needed additional calories to stay fat

• Study ended- return to normal diet

• Few months return to normal weight (maintained)

2 studies: explanation

• Why can’t obese people stay thin after a diet & weight loss?

• Why can’t thin people- forced to gain weight- stay fat?

• Answer: “set point”

• Body metabolism: speeds up or slows down to keep weight= narrow range

• Lose weight: metabolism slows

• Gain weight: metabolism speeds up

• Set point: “each person has comfortable weight range to which body gravitates”

• Going much above or below natural weight range: difficult

• Body resists change: by altering appetite & metabolism

• If set point is working in our bodies, why are so many Americans gaining so much weight?

• Set point- not absolute mechanism • May change over time • Most adults: body weight: ages 30-60

• Reasons? Changes: physiological,

psychological, environmental factors

Any other differences: obese vs. non-obese people?

• Adaptive thermogenesis: related to set point

• Normally: if you overeat once in a while: metabolism, burn extra calories, no weight gain

• If you restrict food intake:

metabolism, conserve energy

• Some studies:

Lose Weight

BMR

Obese people Lean people

BMR: different response

Gain Weight

Obese people Lean people

BMR

BMR: different response

Obese people: may be less efficient in

burning off extra calories

• Other differences? Overweight people may be less active

• People- highest amount body fat:

lowest level of physical activity

• Cause or effect?

• Overweight people: difficulty exercising, daily activities (walking)

• Other differences?

If normal weight people: overfed

Range of weight gain

Low weight higher weight gain

gain

“involuntary exercise”

Fidgeting, restlessness

Do obese people fidget less?

Non-Exercise Activity Thermogenesis

• Wiggling foot, pacing, fidgeting, restlessness

• Mayo Clinic 2005 Study: Lean vs. Obese People

• Lean people: 152 minutes/day more in upright position

Non-Exercise Activity Thermogenesis

Being in upright position

• 152 minutes= non-exercise thermogenesis= 350 calories burned

• 350 calories= 1 hour aerobic dancing

• 350 calories= 1 glazed donut/cream filling

So…. What causes obesity?

• Multifactorial: Genetics, Environment, Lifestyle

Basic problem: Energy Imbalance

• Positive energy balance

• Input > Output

• Calories In > Calories Out

#1 Genetics: genetic predisposition

• 300 Obesity genes identified

• Regulate:

How much food we eat

Amount of energy expenditure

Way fat is stored in body

• Combined effect these genes (normal vs. abnormal): determines how much you weigh & how much fat you carry

• We inherit body shape from parents: some people inherit tall, slender bodies, long thin bones

• Others: stocky bodies, short, wide bones

Genetics- predisposition

2 obese parents: 80% chance- obese child

1 obese parent: 40% chance

2 normal weight 14% chance

parents

Genetic predisposition

• Tendency

• Not absolute

• Monitor diet, regular exercise

• Maintain healthy weight

Adoptees study: nature vs. nurture

• Dr. Albert Stunkard

• Danish adoptee study

• Children adopted: very young age

• Look at body fat as adults

• Adoptee= same body amount fat as biological parents

• No relation: fat of adoptive parents

Identical twins studies

Swedish twin study: identical & fraternal twins

• Some reared apart, others together

• ID twins- nearly identical BMI- no matter where raised

• Fraternal twins: more BMI variation

• Conclusion: body fat/weight: strong genetic influence

• Changes in gene pool- human populations can’t explain rapid increase- obesity- last 10 years

• So what else causes obesity?

#2 Environment/Lifestyle

Genetic vs. non-genetic factors

#2 Environment/Lifestyle

• Americans are eating more calories

• Americans are moving (exercise) less than 30 years ago

• Result: Energy imbalance

• Why is this happening?

Americans are eating more calories

• Food- affordable (cheaper)

• Available: 24 hours/day

Supermarkets, fast food restaurants, convenience stores

• Americans are eating out more often: at mercy of chef/cook- what goes in food

• Children eat 770 calories at restaurants vs. 420 at home

• portions (calories) served since 1970: supersizes

Portion distortion

Hardees Monster Thickburger

TGI Friday’s: new direction

• Known for deep fried potato skins stuffed with cheese, bacon, sour cream

• New “right size” portions

Friday’s “Right Size”

• 1/3 smaller than original

• Cheaper

• But dietician’s complaint: “even trimmed down portions-almost enough food for entire day.”

Americans are eating more calories

• 2 working parents: fewer meals prepared at home

“The family meal is what counts, TV on or off” NY Times 10/16/07 • Children/teens regular meals with

parents: Fruits/veggies Calcium-rich foods Vitamins/nutrients Less junk food Same: with/without TV Key: Togetherness

“Take out” more common

• “The bucket is back” “No trans

fats”

• “You deserve a break today”

• KFC marketing message to busy mom

• More pre-packaged (not fresh) foods ( calories, fats)

• Convenience: busy lifestyle: It’s easier than cooking from scratch

• Social pressures- family: “clean your plate”

• Family: same food, same cooking methods: butter vs. olive oil

• Parties, picnics, barbecues

• Fast food: cheap, high calories/fat, large portions

• Vending machines: high calorie junk food

• Normal daily routine:

coffee & donut break

• Result: body weight

#2 Environment/Lifestyle

American are moving less

• Center for Disease Control: 40% American adults- no exercise/physical activity during leisure time

• Don’t walk/bike to work

• Fewer jobs: physical labor

• Elevators instead of stairs

• Riding vs. push lawnmowers

• Labor saving devices: garage door openers, remote controls- TV

• Longer work day/commuting: no time for physical recreation

• Instead: TV, computers, electronic games (sedentary)

# Steps you take/day

• Typical office worker: 3000- 5000 steps/day

• Amish community (no cars, electric appliances): 14- 18,000 steps/day

• Obesity: 4%

Pennsylvania Amish 2008 Study

• Test for obesity genes

• With obesity genes:

• Likelihood weight gain

• But with high activity

(manual farming)

• Same BMI as

Active Amish without

obesity genes

TV Watching and Body Weight

2007 Kaiser Study: Children & TV

Children (age) TV Food Ads/Year

2-7 4,400

8-12 7,600

Teens 6,000

For each 1 hour TV, children eat 167 calories

Calorie dense, low nutrient foods

Adult TV Watchers

• People who watched TV

2 hours/day

• Greater obesity rate

vs. people who sat

for 2 hours/day

(sewing, reading, writing) without TV

• For every 2 hour increase TV, obesity increases 23%, Type 2 Diabetes 14%

Obesity and TV

• Some researchers: 10,000 steps/day- good fitness level

• 2006 study, monitor overweight people with pedometers

• For every hour TV watched, 144 fewer steps/day

Pedometers

2008 study: Journal

American Medical

Association

• People who use pedometers walk 1 mile more/day than those who don’t

• Lower Blood Pressure and BMI

• Most progress with “step diaries”

Bottom line: most overweight/obesity explained by:

Excess calorie intake

Physical activity

Americans: eating more/exercising less

#3 “My friends made be get fat”

• New theory: Obesity & social networks

• Framingham Heart Study: 2007 (32 years)

• Obesity “spreads” to close friends through social network

• If friend obese: your risk 57%

• Even if friend 100’s miles away

• Reason ?: subliminal message: from obese friend: “being overweight is OK”

Childhood obesity: public health emergency

• 13 million children overweight

Children and Obesity

• Risk type 2 diabetes

• Risk heart disease, high blood pressure

• Risk- early death as adults

• Surgery risks: keeping air passages open; wound infection

Children and Obesity

• Spending more time: TV/computers/video games

• Schools: gym- reduced or eliminated

• After school- concern child safety: children stay inside

Children and Obesity

• Eating foods: calories, sugar, fat

• Food companies: marketing food: children

• TV, movies, fast food restaurants, cell phones, internet, text messaging

• Toys, games, songs, celebrities

Food companies & children

• Kaiser study: 50% TV ad time children’s shows: food

• Ads aimed at children & teens: 72%: candy, snacks, sugary cereal, fast food

Is Shrek obese? What is his BMI?

Is Shrek a good role model for children?

Kellogg to change recipes, marketing

• Concern: marketing junk foods to children: Pop Tarts, Froot Loops, Apple Jacks

• Will stop marketing to children under 12 if foods don’t meet new nutrition standards

• New standards: 1 serving: limit- 200 calories

No trans fats

2 grams saturated fat

230 milligrams sodium

12 grams sugar

• Or Kellogg will reformulate food: challenge: keep good taste

What are parents doing to prevent obesity- children?

• Did you have a personal trainer as child?

• ~1 million

American

children: own

personal trainers- fitness

Exercise can help

• High intensity physical training: 13-16 year old obese teens

• Improves cardiovascular fitness (treadmill test)

• visceral/total

body fat

Derick Sylvestre: Age 13 200 pounds

Joined Whittier Health

Center- Roxbury

Doc, Dietitian, Case

Manager: Lifestyle

Changes: basketball,

jogging, weights, better diet

Now 15 20 pounds

Important: early intervention- overweight children- before 12

Sleep and Body Weight

Adults: University Chicago Study 2010

People in clinic: same food, exercise

Sleep Deprived Adequate Sleep

5.5 hr/night 8.5 hr/night

Same total weight loss

Hungrier Loss more fat

Ghrelin: hormone than muscle

Drives appetite

Bottom line: get enough sleep for weight loss dieting

Children

University Washington

2010 Study

• Children < 5 years: didn’t get 10 hr sleep/night

• 2X more likely: overweight/obese later in childhood

• Sleep: important role in regulating hunger and appetite

Breakfast & Weight Control: UT Study

• Eating substantial breakfast

• Satiation

• Overall daily calories

• ? Relationship: diurnal rhythms/activity

• 100 years ago: less night activity, go to sleep earlier, longer time eating interval until breakfast

Drinking water to lose weight

Clinical Nutrition Insight 2010

• Drinking H20 instead

of other beverages

• Total calorie intake

• Body fat breakdown

• Weight when combined with

hypocaloric diet or exercise

If 75% body fat due to environmental/lifestyle factors, key to weight control: PREVENTION

Common Sense Suggestions: Weight

Control Hark & Deen 2005

• Eat only what you need (calories in= calories out)

• Fill up on fruits & veggies (nutrient dense, low calories)

• More fruits/veggies- less snacking

• Eat an apple before a meal

• Cut out fatty foods (9 calories/g)

Common Sense Suggestions

• Reduce snacks/junk food (empty calories)

• Keep moving: more active you are, more calories you can eat & maintain healthy weight

• Exercise: metabolic rate: during & hours afterward

Common Sense Suggestions

• Exercise: critical- long-term weight control: lose/keep it off

Weight lifting Muscle mass

Burn calories-even at rest

Feel good about self

Reduce fatigue

• Eat smaller portions

Common Sense Suggestions

• Don’t skip breakfast: best overweight protection for teens with one obese parent: eat breakfast every day

• Other studies: eating breakfast obesity

Common Sense Suggestions

• Join a support group: long-term motivation, exercise together

Obesity: How do you treat it?

• Diets/exercise

• Diets: Ornish, Pritikin, Atkins, Zone, Scarsdale, South Beach, Volumetrics, Beverly Hills, Cambridge, SlimFast, Weight Watchers, Jenny Craig, Nutrisystem

VOLUMETRICS

• Eat 3 meals/day + snacks

• Volume of low calorie foods

• Fruits/veggies (H2O), whole grains (fiber) + water

• Protein: fish, poultry (no skin), lean meat (slows stomach emptying, reduces hunger)

• High calorie, low volume snacks, added sugar, candy

• Satiety (fills you up), weight loss

Meal Eaters vs. Nibblers

• 800-1000 calories/day divided in 6-8 meals (nibbling)

• Meal eaters: enzymes fat storage

• Frequent small meals:

1) improve glucose tolerance

2) lower blood cholesterol

• Drugs

Alli (Xenical): approved by FDA (2007) over-the-counter weight loss drug

Alli:

• Blocks breakdown & absorption of fat- intestine

• Blocks calories entering body

• Side effects: diarrhea, flatulence (gas), oily stools

Obesity Treatment: Surgery

• Bariatric surgery

Bariatrics – dealing with obesity

Three fold bariatric surgery- obese adolescents: 2000-2003

• Gastroplasty (stapling), gastric bypass, banding

Bariatric Surgery

1. Gastroplasty: Partitioning or “stapling” stomach section

Reduce total food intake

2. Gastric bypass surgery

A) Attach lower part small intestine to small stomach pouch

B) Food “bypasses” most of stomach/small intestine

C) Less absorption food

3. Gastric banding- reduce stomach size with constricting band: restrict food intake

Bariatric surgery risks: high

• Infection, blood clotting, anesthesia problems, death

• Post-surgery complications: chronic diarrhea, vomiting, dairy food intolerance, dehydration, nutritional deficiencies

Charlie Weis: Patriots, Notre Dame

• Sued MGH surgeons

• 2002 gastric bypass

• Internal bleeding,

permanent nerve

damage, near death

• Brady testified in court: Weis- in/out consciousness- bleeding internally

Bariatric surgery: does it work?

• 33%- 50% people lose significant weight and keep it off (5 years)

• Rest of people: still overeat, stomach pouches enlarge, staples/gastric bands loosen, some die after surgery

Lap-Band

• Silicone ring filled- saline around stomach

• Creates smaller upper pouch & lower stomach

• Controls amount of food

• Minimal surgery

• Adjustable band

• Weight loss

Lap-Band

Cosmetic surgery: Liposuction

Liposuction:

• Removes fat cells-localized areas

• Risks: blood clots, skin/nerve damage, drug reactions, pain, perforation injuries

• Also: deformations in area suctioned

• Millions fat cells remain- can still accumulate fat