LECTURE OVERVIEW WHY DO WE EAT? WHY DOES EATING BECOME DISORDERED? PSYCHOSOCIAL AND BIOLOGICAL...

LECTURE OVERVIEWWHY DO WE EAT?

WHY DOES EATING BECOME DISORDERED?

PSYCHOSOCIAL AND BIOLOGICAL FACTORS

OBESITY, ANOREXIA, BULLIMIA

©John Wiley & Sons, Inc. 2010

Why is eating so complicated?

Eating is a motivated behavior, yet it is also confused with emotion and

can become disordered.


Drive-Reduction Theory


1. Eating to reduce hunger is a good example of the drive theory of motivation.

2. But the arousal theory of motivation explains why we might eat a slice of pumpkin pie after consuming a heavy holiday dinner i.e. stimulation seeking.


• Cannon & Washburn’s early technique for measuring internal factors in hunger


Hunger and Eating

Psychosocial Theories for why eating becomes disordered

• Incentive: motivation results from the “pull” of external environmental stimuli

• Cognitive: motivation affected by attributions & expectations

.

©John Wiley & S

Psychosocial Theories for why eating becomes disordered (cont.)

Behavioral: unhelpfullearned associations

Analytical: expression of inner conflict


Hunger and Eating

• Biological factors: stomach, biochemistry, the brain

• Note the size difference in these rats. The rat on the left had the ventromedial area of its hypothalamus destroyed, the one on the right had

• the lateral hypo.removed.©John Wiley & Sons, Inc. 2010

CHEMISTRY OF EATING?

• Is the ventromedial hypothalamus a satiety center? Is the lateral hypothalamus an eating center?

• Leptin is the hormone that signals satiety in the brain.

• Ghrelin is the hormone that signals hunger in the brain.


Hunger and Eating• Psychological factors:

visual cues, cultural conditioning

• Or Genetic: Obesity is more common in Pima Indians living in U.S., but not for those in nearby Mexico with traditional diet.


Is Obesity a Psychological Issue?

• Obesity results from numerous biological and psychosocial factors.

BMI > 30



• Anorexia nervosa & bulimia nervosa are both characterized by an overwhelming fear of becoming obese & explained by multiple biological & psychosocial factors.

LECTURE OVERVIEW WHY DO WE EAT? WHY DOES EATING BECOME DISORDERED? PSYCHOSOCIAL AND BIOLOGICAL...

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