Notes - February 28, 2014

• Hunger - both physiological and psychological
• Biological Basis of Hunger
• hunger does not come from the stomach but the hypothalamus
• Hypothalamus
• Lateral - when stimulated, it makes you hungry
• Ventromedial - when stimulated, you feel full

How Does The Hypothalamus Work?

• Two Theories
• Leptin - a protein produced by bloated fat cells. Hypothalamus senses rises in leptin and will curb eating and increase activity
• Setpoint - the hypothalamus acts like a thermostat. We are meant to be in a certain weight range when we fall below weight, our body will increase hunger and decrease energy expenditure.
• Body Chemistry
• Glucose - hormone insulin converts glucose to fat. When glucose levels drop, hunger increases.
• Hypothalamus Hormones
• Orexin increases; hypothalamus; increased hunger
• Ghrelin increase; stomach; increased hunger
• Insulin increases; pancreas; increase hunger
• Leptin increase; fat cells; decrease hunger
• PPY increase; digestive tract; decrease hunger

The Psychology of Hunger

• Externals - people eating is triggered more by the presence of food than internal factors
• Internals - taste preferences; when food taste better, we eat faster.

Eating Disorders

• Bulimia Nervosa - characterized by binge eating (eating large amounts of food and purging)
• Anorexia Nervosa - starve themselves to below 85% of their normal body weight. They see themselves as fat; a vast majority are women