8A: Motivation Section 2: Hunger

Physiological Needs (To reduce hunger, absorb nutrients, survive)

Psychological Needs Boredom Comfort Depression Habit

Social Needs Our culture bases most social gatherings, events, and holiday’s around food.

Hunger is all consuming.

Physiology of Hunger What physiological factors produce hunger?

A.L. Washburn found that our stomach has contractions when it is low on fuel. The contractions send a message to our brain that we are hungry.

Glucose – form of sugar in our blood that provides energy for our body. Hunger is our natural indicator that our glucose levels are low.

Hypothalamus Lateral Hypothalamus (causes the hungry feeling) *Hint L.H. = Large Hunger Ventromedial Hypothalamus (suppresses hunger) *Hint V.M.H = Very Minute Hunger

Hormones that enhance or suppress hunger. HORMONE ENHANCES or SUPRESSES? ORIGIN InsulinEnhancesPancreas LeptinSuppressesFat cells OrexinEnhancesHypothalamus GhrelinEnhancesEmpty Stomach ObestatinSuppressesFull Stomach PYYSuppressesFull Digestive Track

Psychology of Hunger What psychological and cultural factors influence hunger?

Time/Memory/Expectations – as time goes by we are conscious of when we last ate and expect to be hungry again by a certain time. Amnesia patients continue eating meals that are placed in front of them 20 minutes apart.

Stress – people under stress crave carbohydrates because carbs boost serotonin levels, which has a calming effect.

Food Aversions – bad experiences with a certain food can cause us to have a psychological aversion to it.

Cultural Norms – every culture has foods that they find to be delicious that other cultures find repulsive.

Social Facilitation – people use food as a psychological crutch in stressful social settings.

Unit Bias – when offering a choice in portion size, people will always choose the larger size.

Eating Disorders EATING DISORDER CHARACTERISTICS Anorexia Nervosa Even though the person is 15% (at least) below healthy body weight, they feel fat, fear gaining weight, obsessed with losing weight. Addicted to exercise. Bulimia Nervosa Binge-eating and purge cycle. Mostly late teens/early twenties. Depression and anxiety follows binges. Weight fluctuates so its harder to diagnose. Binge EatingEpisodes of overeating following psychological anxiety, stress, or guilt. Not followed by exercise or purging.

Discussion Questions 1)In America how has our culture contributed to eating disorders? 2)How/why do standards of beauty change around the world?

Eating is a biopsychosocial behavior EATING Social Cultural media images affect our eating habits/disorders social gatherings/holidays often revolve around food Psychological stress anxiety, mood, affect our levels of hunger unit bias affects how much we eat memory and time affects how frequently we eat Biological hormones send messages to the brain regarding fuel and energy levels hypothalamic centers in the brain control appetite

Obesity and Weight Control What factors predispose someone to become and remain obese?

BMI (Body Mass Index)

5 Dangers of Obesity 1 – diabetes 2 – cancer 3 – high blood pressure 4 – heart disease 5 – arthritis * The economic cost in health care to treat these diseases each year in in the billions of dollars. Watch “Obesity in America”

calories put in the body vs. calories used by the body = weight gain or weight loss

Weight Loss: fat cells can decrease in size but will never decrease in number.

The problem of metabolism and weight: Compared with other tissue, fat has a lower metabolic rate (it takes less food energy to maintain itself). The more you weigh, the less you have to eat to maintain your weight. So eating less calories than the skinny guy isn’t going to help. The skinny guy can eat more than you and still burn off the calories quicker because he has less fat cells which means a higher metabolic rate.

Strategies for losing weight a.start only when you are motivated to do it. b.keep unhealthy food out of the house. If it’s not there you can’t eat it. c.be as active as possible d.eat healthy e.eat on a regular schedule f.don’t binge eat. Be mindful when you are eating

Evidence that weight has a genetic component: A. Adoptive siblings do not have similar body types despite being fed the same meals. B. Identical twins, even when raised apart, had a body weight correlation of +.74 C. Girls and boys are 3-6 times more likely to be obese if they have an obese parent. D. Scientists have pinpointed a gene called FTO that doubles the chance of becoming obese.

Environmental Factor How Does it Affect Weight? Sleep Loss Less leptin is produced so the brain doesn’t receive body fat messages; more ghrelin is produced, which triggers hunger. Social Influence Odds of gaining weight triple when a close friend gains weight. Changing Food Consumption Sugary foods and drinks, along with fast food are altering our body shapes. Changing Activity Levels Leading less active lives means burning less calories. Portion sizes Businesses offer bigger portions for lower prices, which entices us to eat more.