Hunger, Eating Disorders and Obesity

1
Hunger, Eating Disorders and Obesity
2
Set Point Theory

• The point at which an individuals weight
  thermostat is supposedly set.
• When the body falls below this weight, an
  increase in hunger and a lowered.
• Metabolic rate may act to restore the lost
  weight.

3
Basal Metabolic Rate

• Bodys base rate of energy expenditure when at
  rest.
• Calorie input vs. Calorie output
• 3500 calories in 1 pound of fat!! Yum, Yum!

4
Stomach contractions accompany our feelings of
hunger
Subject presses key each time He feels hungry
Subject swallows balloon, which measures
stomach Contraction
(Washburn, 1912)
5
The hypothalamus controls eating and other body
maintenance functions.
6
Hypothalamus Hormones
The hypothalamus monitors a number of hormones
that are related to hunger.
7
Some Appetite Hormones

• Orexin
• Hunger triggering hormone secreted by the
  Hypothalamus.
• Ghrelin
• Hormone secreted by empty stomach.
• Im Hungry.
• PYY
• Digestive Tract Hormone.
• Im Full.

8
Leptin

• A hormone involved in hunger regulation is
  leptin.
• Fat cells in the body secrete leptin and release
  it into the blood.
• When the leptin level in the blood is high,
  hunger decreases.

9
Hypothalamic Centers
The lateral hypothalamus (LH) brings on hunger
(stimulation). Destroy the LH, and the animal has
no interest in eating. The reduction of blood
glucose stimulates orexin in the LH, which leads
rats to eat ravenously.
10
Hypothalamic Centers
The ventromedial hypothalamus (VMH) depresses
hunger (stimulation). Destroy the VMH, and the
animal eats excessively.
Richard Howard
11
Glucose C6H12O6

• The glucose level in blood is maintained. Insulin
  decreases glucose in the blood, making us feel
  hungry.

Glucose Molecule
12
Glucose the Brain

• Levels of glucose in the blood are monitored by
  receptors (neurons) in the stomach, liver, and
  intestines. They send signals to the hypothalamus
  in the brain.

Rat Hypothalamus
13
Glucose

• The form of sugar that circulates in the blood
  stream.
• Provides the major source of energy for body
  tissues.
• When its level is low, we feel hunger.

14
Insulin

• Insulin allows cells to access glucose in the
  blood.
• When the pancreas secretes insulin, hunger
  increases.

15
Diabetes

• Diabetes is a condition caused by a deficiency of
  insulin.
• The cells in the body are not able to access the
  glucose in the blood.
• Type 1
• Type 2

16
Social Impact of Hunger

• Body Image
• Eating Disorders

17
(No Transcript)
18
Anorexia Nervosa

• When a person is less than 85 of their normal
  body weight.
• 95 of sufferers are female, most are between the
  ages of 18-30 and Caucasian.
• Approximately 20 of persons diagnosed with
  anorexia nervosa die.

19
Bulimia Nervosa

• Disorder characterized by episodes of overeating,
  usually of highly caloric foods, followed by
• vomiting
• laxative use
• fasting
• excessive exercise

20
Cathy Rigby Little Girls in Pretty Boxes

• "When I hit puberty and went up to about 104
  pounds two or three months later, I worked a
  little harder at either starving myself or
  becoming bulimic."

The first American woman to win a medal in World
Gymnastics competition. She holds 12
international medals, eight of which are gold.
While Cathy excelled in the Olympics, she also
suffered from an eating disorder.
21
Reasons for Eating Disorders

• Sexual Abuse Childhood sexual abuse does not
  cause eating disorders.
• Family Younger generations develop eating
  disorders when raised in families in which
  weight is an excessive concern.
• Genetics Twin studies show that eating disorders
  are more likely to occur in identical twins
  rather than fraternal twins.

22
Environmental Factors

• Availability of rich foods

23
Environmental Factors

• Preferences
• Conditioning, Observational Learning
• Supersize Me

24
Environmental Factors

• Stress

25
Environmental Factors
Portion Size

• Cultural attitudes
• Ideal Body Size

26
Obesity

• 65 of Americans, according to the Center for
  Disease Control
• High risk of early death
• Diabetes (Type 2)
• Heart Conditions
• Lack of Exercise

27
Social Impact of Obesity

• Obese people are less likely to be
• Married
• Happy
• Make Money (7,000 less than thinner people with
  same qualifications)

28
Physiology of Obesity

• Fat Cells
• Typical adult has about 30 million fat cells.
• They can divide into more
• They will not disappear

29
Summary