FACT:  In the U.S., obesity is most common among lower-income people. However, people who live on extremely low incomes seldom suffer from eating disorders such as bulimia and anorexia nervosa.  WHY?

Hunger: The Greatest of All Motivators

What causes hunger? It’s more complicated than you’d think!  It does not only happen with stomach contractions and an empty stomach  People who have had their stomachs removed still feel hunger!

Biochemistry of hunger

How do you know when to stop eating?

Metabolism  The body is predisposed to maintain itself at a particular weight (set point); “weight thermostat”

The Psychology of Hunger  Rozin (1998): offered two patients with anterograde amnesia a lunch three times, twenty minutes apart- and they ate them all!  The point of the story:

External factors  Eating is a social experience.  We usually eat more when in the presence of others.  Hunger can be triggered more by the presence of food than by internal factors.  Rodin study (1984):

Stress, anxiety, and mood  Carbohydrates help boost the neurotransmitter serotonin, which has calming effects.

Taste preference  We are genetically wired to crave sweet, salty, and fatty foods, all of which are rare in nature.

America’s Battle of the Bulge  66% of Americans are overweight  Obesity rate has doubled for adults in 40 years;34% of American adults are obese (30% above one’s recommended weight); obesity rate for kids has quadrupled  25% of adults are on diets at any given time; most dieters eventually regain most or all of the lost weight

Why is it so hard to lose weight?  People gain fat by consuming more calories than they expend  A pound of fat = 3,500 calories  A typical adult has billion fat cells  Obese people have about 75 billion fat cells and they may be 2-3 times their normal size  The number of fat cells never decreases, though they can shrink

Our unhealthy environment  Sleep loss:  Decreasing activity levels:  Energy-saving technology:  Commuting:  Greater availability of cheap, processed junk food high in calories, low in nutrition:

Eating disorders  At the same time, rates of anorexia, bulimia, and binge- eating disorders are increasing  Over 50% of U.S. women feel negatively about their appearance  “An increasingly stringent cultural standard of thinness for women has been accompanied by a steadily increasing incidence of serious eating disorders in women.” -Susan and Orland Woolsey (1983)  Those who watch TV 3 or more nights a week were 50% more likely to describe themselves as “too big or fat”

The island of Fiji: a case study about the impact of culture. world/study-finds-tv-alters-fiji- girls-view-of- body.html?pagewanted= stm y/2009/03/fijian-girls-succumb- to-western-dysmorphia/ What can we learn about the issue of cultural influence and media from this case study? What larger conclusions can be drawn about human nature?