CH 11- MOTIVATION THE PHYSIOLOGY OF HUNGER- Body chemistry: different metabolic rateso May be due to early childhood eating habitso Genetic- Braino Hypothalamus Lateral region (brings on hunger)- Destroyed->starve Ventromedial region (depress hunger)- Destroyed -> continue to eat- Role of Ghrelino Hormone that increases before meals and decreases aftero Linked to appetiteo PYY chemical: suppresses appetite in mice for a short time.o Lectin: secreted by fat cells, seems to diminish the reinforcing impact of food- Set point hypothesis: diff. people have a set point/set weight that they gravitate back to if they gain or lose weight. Not fixed in stone: changes in adult life span. But we do have a set point (once we achieve a certain weight, our body tries to keep it there): may be determined by body chemistry, genetics, metabolic rate, etc.o # of fat cells when we lose weight we don’t lose fat cells, they just get smaller in size: more cells, tiny.- When the cells become small, they send out signals that say that you’re hungry because they’ve shrunk. Can signal metabolism to slow down: challenges weight loss,yo-yoing in weight. 85% gain it back. Long term weight loss: difficult for us as a culture. Body chemistry, set points.- External incentiveso Smell of food: walking by a restaurant and smelling the food and wanting it, even if you ate alreadyo Visual of food: seeing an ad for pizza -> order pizzao Some are more susceptible to the external signals, might be due to: Eating habits established over the life span- Taste-preference (Culture)o We learn to like different foods.o Children: reluctant to try new foods Why? Adaptive: cautious, avoid any potentially toxic/new foods Need to try foods well over 30 times before they actually eat itOBESITYo Drawn towards sweet thingso When food is available, we eat it. Because our body thinks we may have to face famine: historical drive.o Genetics and heritability Weight correlates around .74%- Concordance rate of identical twins, .74%similarity- Concordance rate in fraternal twins = .32%o Fat cellso Culture Becker et al Fiji Adolescent Girls Study (2002) Ideal beauty: heavy.- Western television came to Fiji during the course of the study. Tv in every household while doing the studyo Interviewed girls: gave them the “EAT” eating attitudes test. Use for people with eating disorders  Increase in eating disorders/body image disorders post-western tv exposureSigma of Obesityo Obese children are viewed negatively by peerso Gender and obesityo Obese women: gender interaction with obesity. Stronger effects for obese women:o Receive lower salarieso Victims of discriminationo Less likely to marryo Often the victims of “weightiest” commentso Study on pre-school children: found that children didn’t want to sit with heavier students.o Asked to tell what the heavier kids ate: said ‘gross’ foods because they’re ‘gross people’ “ate poop, dirt, sticks, etc”o Media consumption -> sedentaryEATING DISORDERS o Anorexiao 1/50 girls affected (only about 5-15% are boys)o more common in Caucasian americans than in African americans o peaks in early adolescence o symptoms appear before menarchy(first period) if starving is severe enough, the period/ovulation doesn’t occur. Need a certain amount of body fat to support pregnancy.- Can affect fertility permanently if ovulation does not occur for an extended period  “Fat-spurt”: natural weight gain in adolescence- To support pregnancy and lactation- Girls tend to hit puberty 2.5 years before boyso Might contribute to the development of anorexia:seeing that the boys are thinner and smaller thanthey are.o 4% die: highest death rate of all the mental disorders anorexia can be life threatening.  Damage to the heart muscle- Starve -> lose muscle incl. heart muscleo What role does the media play? There are girls with anorexia that give ADVICE to other girls on HOW to maintain an anorexic life-style, how to trick your friends and family: eating lettuce with mustard, ice cubes, sucking on a rock, exercising in the shower, etc. THIN models in the mediao Kat’s story: 26 y.o now & “healing”. But physical consequences remainBut WILL have osteoporosis in her 40s, guaranteed.  Physical consequences: hair fall-out in chunks, toenails and fingernails falling off, swelling aches/sore in ankles, wrists, etc.- Calcium deficiency -> aches and soreness- Brittle bones: ribs were at risk of cracking- Rotten teeth: need to take them all out- Bowels: pooped out her own stomach acid because there was no food, peed herself even when she coughed:couldn’t control her urine. o 2-3 days: enema’s  blames only herself but in reality culture has an influence. In early adolescence we don’t have the cognitive ability to determine the consequenceso criteria: profound fear of becoming obese disturbance of body image: “never thin enough” weight loss of at least 25% body weight refusal to maintain a healthy body weight no physical illness that would account for the weight loss beyond anorexiao Bulimiao May not be under weighto Tissue damage in the throat from vomiting: stomach acido Damage to teeth: from constant acid exposure. Wears out the enamel:translucent appearance->begin to look blacko One study: found 19% of college age women exhibited symptoms of bulimia. Bulimia and anorexia are Under-diagnosed o Can be fatal (3.9% less than anorexia) Throws body chemistry off. - potassium Heart problem: arrhythmia (failure to beat), heart attackso Criteria: Episodic binge-purging Use/abuse of laxatives Not being able to stop binge/purging voluntarily Depressed mood, self deprecating thoughts: shame and humiliation associated with purging Repeated attempts following binging, to control weight dieting. Then a fall back to bingeing and purging Does society contribute to eating disorders? YESWhat messages do we take from the media?Ex: little mermaid: Ursula- Disney villians tend to have physical standards: be obese or skeletally thin. Original little mermaid story: young girl who has each of her sisters who get to see the world above the ocean. Goes to sea-witch and makes a bargain: tongue gets cut off. Every step she takes on land is like stepping on knives, if she doesn’t get the prince she loses her soul. In the end she didn’t get the prince and turned into sea foam. Ideal body image for women in the past: pale= didn’t