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Hunger Hunger is both physiological and psychological.

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Presentation on theme: "Hunger Hunger is both physiological and psychological."— Presentation transcript:

1 Hunger Hunger is both physiological and psychological.

2 Physiology of Hunger Washburn’s studies showed hunger was partially related to the stomach. But those with their stomachs removed still feel hunger.

3 Body Chemistry Glucose The hormone insulin converts glucose to fat. When glucose levels drop- hunger increases.

4 The Brain In the 1960’s it was discovered that hunger comes from……….. The Hypothalamus

5 The Hypothalamus & Hunger lateral hypothalamus: brings on hunger by triggering orexin (hunger arousing hormone). Stimulate the lateral hypothalamus and even a well fed animal will begin to eat. Lesion the lateral hypothalamus and a starving animal will have no interest in food.

6 The Hypothalamus and Hunger ventromedial hypothalamus: depresses hunger. Stimulate the ventromedial hypothalamus and the animal will stop eating Lesion the ventromedial hypothalamus the animal will continuously want to eat.

7 The Physiology of Hunger Body Chemistry and the Brain Appetite hormones –Ghrelin – hunger arousing hormone –Obestatin – suppresses appetite –PYY – secreted by digestive tract: suppresses appetite –Leptin – protein secreted by fat cells that diminishes the rrr rewarding pleasure of food

8 How does the hypothalamus work? Leptin Leptin is a protein produced by bloated fat cells. Hypothalamus senses rises in leptin and will curb eating and increase activity. Can leptin injections help me? Set Point 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 (Basic Metabolic Rate). What happens if we go above our set point? Two Theories

9 The Psychology of Hunger Externals: people whose eating is triggered more by the presence of food than internal factors.

10 Taste Preferences Food taste better and we chew less when we are hungry (beginning of a meal). Food tastes worse and we chew more when we are not hungry (at the end of the meal). Its weird, the better the food tastes, the less time we leave it in our mouths.

11 Psychology of Hunger

12 Eating Disorders Anorexia Nervosa An eating disorder in which a normal weight person diets and becomes significantly underweight, yet, still feeling fat, continues to starve.

13 Eating Disorders Bulimia Nervosa An eating disorder characterized by episodes of overeating, usually of high caloric foods, followed by vomiting, laxative use, fasting, or excessive exercise.

14 Are these disorders cultural? Does gender matter?

15 Body Image

16 Obesity and Weight Control Historical Reasons: –Fat helps body through periods when food is scarce –In developed nations old rule is dysfunctional Obesity = BMI of 30+ Life expectancy

17 Obesity

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20 The Social Effects of Obesity Weight discrimination Psychological effects of obesity –25% increase in depression and anxiety

21 The Physiology of Obesity Fat Cells

22 Genetics & Obesity –Body weights resemble biological parents –Identical twins have similar weights +.74 correlation –Obese parents = obese children 3X box 6X girl

23 Environmental Factors & Obesity –Sleep loss –Social influence –Food consumption and activity level

24 Obesity and Weight Control Losing Weight Realistic and moderate goals Success stories Attitudinal changes


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