Metabolism - Hunger and Appetite:

Question 1

Appetite v. Hunger

Answer 1

• Appetite: a psychological reaction that stimulates a physiological response such as salivation; i.e. a conditioned response to food.
• Hunger: a physical reaction that includes chemical changes in the body from a prolonged period without eating; i.e. the need for food.

Question 2

Appetite & Evolution

Answer 2

• To hunter-gatherers, foods with a high fat or sugar content offered a survival advantage.
• Consequently, these foods strongly stimulate the dopamine reward system.
• Obese people have been shown to have reduced numbers of dopamine receptors in their brains & get less of a reward response from palatable foods.
• More repeated intake of palatable food results in down regulation of dopamine receptors.
• This can increase the risk of over-eating.