4.7c Motivation: Hunger Motivation

AP psych

Set point

the point at which the “weight thermostat” may be set. When the body falls below this weight, increased hunger and a lowered metabolic rate may combine to restore lost weight.

ex;

• Weight Loss Example: If someone goes on a restrictive diet and loses weight quickly, their body may respond by increasing hunger and slowing metabolism to push their weight back toward the set point.

• Weight Gain Example: If a person overeats for a short period, their metabolism might speed up to burn extra calories and prevent long-term weight gain.

Increased appetite

• Ghrelin: hormone secreted by empty stomach; sends “im hungry” signals to the brain

• Orexin: hunger-triggering hormone secreted by hypothalamus

Decreases appetite

• Leptin: protein hormone secreted by fat cells; when abundant; causes the brain to increase metabolism and decrease hunger

• PYY: digestive tract hormone; sends “im not hungry” signals to the brain

Basal metabolic rate

the body’s resting rate of energy

Obesity

defined as a body mass index (BMI) measurement of 30 or higher, which is calculated from our weight-to-height ratio.

(individuals who are overweight have a BMI of 25 or higher)