In the 1950s, Ancel Keys used volunteers from the
US Army to study hunger.
Weight dropped & stabilized at 75% of normal
Concluded that hunger is a response to a
homeostatic system designed to maintain normal
Washburn and Cannon found that appetite
lessens if the stomach is shrunk (because
there is less ghrelin)
And older theory was based on the body’s set
point, or natural weight.
If the body was heavier, then it increased the
basal metabolic rate; if lighter, it decreased the
The body depends primarily on glucose for its
Insulin (from the pancreas) decreases the
amount of glucose in the system by converting it
Leptin is produced by fat cells and decreases
Taste preference is
There is a genetic predisposition to like sweet
and fatty tastes, but dislike bitter.
There is a genetic distrust of novel foods.
You like what you know and are familiar with.
(mere exposure effect)
Three major eating disorders:
Anorexia nervosa is a condition
wherein a person is purposefully 15%
below their normal weight (BMI < 16)
Between ½-1% of Americans suffer
from anorexia nervosa.
Anorexia has the highest mortality
rate (5-10%) of any psychological
Bulimia nervosa is a condition
involving cycles of binging and
Obesity is the most
disorder in the
• BMI of 30 or higher
• Check your BMI: