Module 35: Hunger Unit 10: Motivation

Hunger Ancel Keys ( ) was an American scientist who studied the influence of diet on health. He conducted The Minnesota Starvation Experiment as WWII was coming to an end! He used 36 male volunteers and semi- starved them for 24 weeks.

Hunger Results: The participants lost 25% of their body weight. They had increased depression, hysteria, and hypochondria. Some self-mutilated (one subject cut 3 fingers of his hand with an axe). Sexual interest was reduced as were all other interests, except food. Could pass Maslow’s first need.

Hunger Stomach contractions accompany our feelings of hunger Time in minutes Subject swallows balloon, which measures stomach contraction Subject presses key each time when hungry Stomach contractions Hunger pangs

Hunger Glucose: the form of sugar that circulates in the blood. It provides the major source of energy for body tissues. When its level is low, we feel hunger. Also stimulating one part of the hypothalamus increases hunger. Stimulating a different part decreases hunger.

Hunger Orexin: Hunger-triggering hormone. Ghrelin: Hunger-arousing hormone secreted by an empty stomach. Gastric bypass surgery seals off part of the stomach resulting in less Ghrelin. Leptin: Hunger-dampening chemical secreted by fat cells. PYY: a digestive hormone that suppresses appetite.

Hunger Set Point: the point at which an individual’s “weight thermostat” is supposedly set. When the body falls below this weight, an increase in hunger. A lowered metabolic rate may act to restore the lost weight. Basal Metabolic Rate: Body’s rate of energy expenditure.

Hunger Researchers have doubts about a set point, but instead prefer a settling point. Settling Point: the level at which a person’s weight settles in response to caloric intake and expenditure.

Psychology of Hunger As time passes since we last ate, we expect to eat again and get hungry. Carbohydrates boost levels of serotonin, which calms us. Culture and biology affects the foods we crave. We avoid unfamiliar foods (neophobia), which protected our ancestors from potentially toxic foods.

Psychology of Hunger 2/3 of Americans are considered overweight. 1/3 of those overweight are obese. Body mass index (BMI): a way of measuring obesity. Obesity causes a multitude of health issues.

Eating Disorders Anorexia Nervosa: a normal weight person diets and becomes significantly (over 15%) underweight, yet still feels fat and continues to starve. 95% of sufferers are female. Most are between the ages of % of persons diagnosed with anorexia nervosa die.

Eating Disorders Bulimia Nervosa: disorder characterized by episodes of overeating, followed by vomiting, fasting, or excessive exercise. Eat up to 20,000 calories and then starve or purge (vomit). Average victim is a young female of average weight. Takes physical and psychological toll

Women’s Body Images Thinnest Women’s ideal What women believed men preferred What men actually preferred Women’s current body image Fattest