Psychology2016

372 CHAPTER 9

obesity increase dramatically and quickly (Barsh et al., 2000). Foods become more var-

ied and enticing* as well, and an increase in variety is associated with an increase in

eating beyond the physiological need to eat (Raynor & Epstein, 2001). In industrialized

societies, when workers spend more hours in the workplace, there is less time available

for preparing meals at home and more incentive to dine out (Chou et al., 2004). When

the “dining out” choices include fast food and soft drinks, as is so often the case, obe-

sity rates increase. In sum, as cultures become more industrialized and follow Western-

culture lifestyles, negative aspects of those lifestyles, such as obesity, also increase. Over

the last 20 years, rates of obesity in developing countries have tripled. Specifically, this

is a trend in countries that have adopted the Western lifestyle of lower exercise rates and

overeating—especially those foods that are cheap but high in fat and calories. In China,

as well as many countries in the Middle East, Southeast Asia, and the Pacific Islands,

10  to 25 percent of children have been found to be overweight and another 2 to 10 per-

cent are obese (Hawley et al., 2014; Hawley & McGarvey, 2015; Hossain et al., 2007).

Stress also contributes to obesity. One study found that female children of military

personnel, for example, seem to be at a higher risk for eating disorders, including obe-

sity, a risk that may be associated with higher rates of depression (Schvey et al., 2015).

Related to stress is how much sleep we get, and sleep disturbances are also a factor in

weight gain (Roane et al., 2015). to Chapter Four: APA Goal 2: Scientific Inquiry

and Critical Thinking: Weight Gain and Sleep.

As mentioned earlier, metabolism slows down as people age. Aside from not

changing the eating habits of their youth and lowering their intake, as they earn more

income, people also often increase the amount of food they consume, thereby assuring a

weight gain that may lead to obesity. The United States has the highest rate of obesity in

the world: A third of its population is now obese (Flegal et al., 2012; Friedman, 2000, 2003;

Marik, 2000; Mokdad et al., 2001; Ng et al., 2014; Ogden et al., 2014).

Why People Eat

hunger

impacted by insulin response; insulin (normally released more after onset of eating) reduces level of glucose

in bloodstream (resulting in lower blood sugar and increased hunger); glucagon increases level of glucose

ventromedial area of the hypothalamus may be involved in stopping eating when glucose level goes up;

lateral hypothalamus appears to influence onset of eating when insulin level goes up

hunger and eating behaviors are influenced by social cues and convention (e.g., eating at certain times),

culture, and gender

person’s weight set point and basal metabolic rate are tied to hypothalamus, and the hormone leptin

appears to affect appetite

anorexia nervosa

binge-eating

disorder

bulimia nervosa

maladaptive eating

obesity: body weight 20% or more over ideal (based on height);

significantly impacted by genetics, overeating, exercise, and changes in metabolism

to Chapter Twelve, Psychological Disorders

Concept Map L.O. 9.6, 9.7

Interactive

Reset

*enticing: attractive, desirable.

This family is becoming more typical in the
United States as obesity rates continue to
rise. How much of the excess weight on
each of these family members is caused by
poor choices in diet and lack of exercise,
and how much might be caused by
inherited biological factors?