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Chapter7-3.ppt

Chapter 7: Weight managments

Obesity

Obesity is a term used to describe a body weight that is much greater than what is healthy. If you are obese, you have a much higher amount of body fat than is healthy or desirable.
Adults with a body mass index (BMI, calculated as weight in kilograms divided by height in meters squared) between 25 kg/m2 and 30 kg/m2 are considered overweight.
Adults with a BMI greater than or equal to 30 kg/m2 are considered obese.
Anyone who is more than 100 pounds overweight or who has a BMI greater than or equal to 40 kg/m2 is considered morbidly obese.

33%

So what causes obesity?

Overeating is an obvious cause, remember, just 4 g of fat per day is 8 pounds per year!!!
Genetics, effects metabolism, energy storage, obese parent = obese kids
(opposite is true)
Adoption (no correlation)
Twins raised by different parents (usually the same weight, especially identical twins)

80%

So what causes obesity?

Lipoprotein lipase (LPL), enzyme that increases fat storage
More fat leads to more LPL
Obesity gene (ob), codes for protein called leptin
Hormone secreted by fat cells, more fat equals more leptin, suppresses appetite, like most drugs, we can acquire a resistance
Defects in gene lead to obesity, not common in obese people though

LPL

Fat storage

Big Meal

Lower ghrelin levels

Lower Appetite

So what causes obesity?

Ghrelin, works in opposite direction of leptin, stimulates appetite and efficient energy storage
Produced by hypothalamus
Large meals (more calories) leads to lower ghrellin levels
Higher in lower weight people
Less decrease after meal in obese people
Increased levels in people with Prader-Willi syndrom
Makes you hungry when fasting, dieting is hard

After meal levels/Appetite

So what causes obesity?

So what causes obesity?

Set point theory, body weight is physiologically regulated like temperature and BMR
Your body picks a “set” weight and tries to stick to it
Large losses or gains are rapidly counteracted (Eating pizza once in a while won’t make you gain weight [mostly true])
Changes with age
Obesity causes a very sticky set point, hard to counteract
Goal: 1-2 lbs/wk, no more than 10-15% of body weight in a year

So what causes obesity?

Environmental stimuli, what’s popular, what’s available, what’s cheap, portion sizes, fat content of food eaten/served

So what causes obesity?

So what causes obesity?

Lack of physical activity, decreases energy output, lowers BMR, increases appetite (through boredom)

How to treat obesity

How not to treat obesity

Weight loss supplements
$2Billion per year spent (mostly by women)
Many contain harmful ingredients (stimulants)
Side effects are severe (organ failure, stroke, death)
Alli (orlistat) only FDA approved OTC weight-loss pill
Herbal supplements
Many contain toxins, Belladonna, Hemlock, Sassafras
No need for FDA approval, “dietary supplement” no drug
Ephedra (ma huang), banned, dangerous
Other gimmicks
Hot baths, rooms, underwear don’t work
Cellulite is a made up word with no real scientific meaning hence all products intended to treat are lying

Aggressive treatments

Sibutramine, suppresses appetite
Orlistat, inhibits fat digestion
Surgery, gastric bypass, gastric banding, limit food intake by making stomach smaller

Healthy ways to lose weight

Nutritional goals for weight loss

Maintain nutritional adequacy
Small portions, helps curb appetite through constant feeding
Lower energy density, foods that fill you up but don’t have lots of calories, fruits, veggies
Reduce sugar and alcohol consumption
Meal spacing, eat every couple hours
Lots of water

Physical goals for weight-loss