Eating

Eating

I. Physiological Influences

A. Homeostasis

B. Glucose (blood sugar)1. Increased level of a hormone (__?__)

diminishes blood sugar

2. Hunger increases when blood glucose level drops

C. Hypothalamus1. Regulates hunger, thirst, and sex

What happens if you lesion the VMH?

LH and VMH Dual Centers criticisms

• Not simply on-off switches– LH and VMH are elements, but not the elements

• Modulation of hunger today comes from the arcuate nucleus and the paraventricular nucleus– Arcuate nucleus SUPER sensitive to incoming

hunger signals and satiety signals

Conclusion

• Does the stomach regulate hunger?

• HELL TO THE NO. Period.

What regulates hunger?

• Insulin – Secreted by pancreas (which system in the

body is that?)– Inadequate supply of insulin = diabetes

• Insulin levels increase when people eat• Insulin secretion plays role in determination of

hunger

2 other hunger related hormones

• Gherlin – causes stomach contractions and promotes hunger– After food consumption, upper intestines

release hormone CCK = satiety signals to the brain

• Think Louis C.K….

“The meal is not over when I’m full. The meal is over when I hate myself…”

• Leptin– Circulates in blood stream to provide

hypothalamus with information about fat stores

– High levels = lower feelings of hunger

Putting it all together

• Where do leptin, gherlin, CCK, and insulin converge? Stomach or hypothalamus?

• Hunger happens in so many places – neural circuits, neurotransmitters, digestive processes, hormonal fluctuations– All in all – it’s a decentralized mess

• How can you then link that to body weight fluctuations and regulation of diet? Why is there no one cure for mass increase in weight?

II. Sensory Influences

A. Taste, smell, mouth feel, and sight all influence wanting and liking

B. Sweet taste can stimulate appetite by triggering release of __?__ , causing a drop in blood ___?___

C. Wanting and liking of most foods is based on experience

• Preference based on consequences of eating (nutrition, nausea, etc)

• Have you ever eaten something so much that you, to this day, never want to eat it again?

III. Socio-cultural influences

A. People eat more when in a group than alone (social coaction)

• True for western women? Roles of femininity• http://www.youtube.com/watch?v=9YfvBbxE1vU

B. Family and cultural practices related to eating and meal customs

– “CLEAN YOUR PLATE, MISTER!”

C. Cultures have rules about appropriate occasion of eating– i.e. birthday cake, insects taboo or delicacy?

IV. Obesity

A. Genetic influences1. Evolution of thrifty genes

2. Body weight regulation vary among individual’s tendency to become obese

B. Fat cells1. fat cells increase, rarely decreases2. Causes of increasea. early childhood eating patternsb. adult overeating

3. Weight-loss diets shrink fat cells, but does not destroy them

C. Set point

1. The particular level of weight the body strives to maintain

2. Obese people’s set points are higher than average range

D. Metabolism – rate of expenditure

1. varies among individuals (two people can eat the same and have different weights)

2. diets cause lower metabolic rate, making it harder to lose weight

- how should you diet then?

E. Socio-cultural influences on obesity

1. parents using food as reward

2. media

3. abundance in high calorie foodhttp://www.youtube.com/watch?v=N2diPZOtty0

http://www.youtube.com/watch?v=B-tv7iUsb4I

V. Eating disorders

A. Anorexia nervosa1. Diagnosis based on

a. Significantly underweight (below 85% normal)

b. Distorted view of body size/shape

c. Fear of gaining weight

d. Menstruation stops in post-pubertal females

2. Predisposing or maintaining factors

a. genetic influencesb. cultural influences

- objectification theory: women and girls tend to acculturate body image to outside expectation

- African American girls report more positive body images than white or Latina girls

c. Preference for thinness in sports (ideal body size)

B. Bulimia nervosa

1. Diagnosis based ona. Repeated episodes of overeating, followed

by vomiting, laxative use, and/or excessive exercise

b. Undue concern with body size or shape

2. Predisposing or maintaining factorsa. Geneticb. Culturalc. behavioral

C. Methodological Considerations

1. When people who are obese or have an eating disorder are compared to those who do not, distinguishing what causes the problem from having the problem can be difficult.

• Just having the problem changes thoughts, feelings, and behavior

• “Why don’t you just eat less/more? Duh…”• Way off…