Health PsychologyChapter 15 Eating amp; Dieting.PPT

Health PsychologyChapter 15: Eating Dieting Mansfield University Dr. Craig, Instructor The Digestive System Human body converts foods (plant and animal tissue) into usable components (fats, proteins, carbohydrates, vitamins minerals). Materials transported through bloodstream to need areas or to be stored Salivary glands- part of taste sensation, contains enzyme to break down starches Peristalsis-rhythmic contraction and relaxation of muscles lining digestive tract starting in esophagus in the stomach it moves food and mix with gastric secretions (high acidity) such as pepsin which works on proteins. Digestion Continued Small Intestine balance pH of “stomach mix” by secreting alkalinic pancreatic juices that also help digest CHO and fats absorption of starches fats broken down by bile salts stored in gall bladder and made in liver fluids absorbed and nutrients/electrolytes extracted Large Intestine further absorption of H20 and manufacture some vitamins The Brain Hypothalamus and hyper insulin secretion-- adipose Cholecystokin (CCK)- satiety; Leptin- reduced food intake, increased activity levels Weight Maintenance Weight flux: calories burned =calories consumed Consumed CHO (sugar, starches) 4 kcals/gram Proteins 4 kcals/gram Fats 9 kcals/gram Alcohol 7 kcals/gram Fats= highest concentration of kcals, alcohol most selectively taken by system Burned daily metabolism activities of daily living exercise metabolism varies individually, and under different conditions consider weight loss and gain research!! Experimental Starvation Ancel Keys Research on Normals Design- 3 months as usual eating Reduce ration until 75% of current weight (half-rationing) 3 months refeeding Results rapid weight loss pace originally that slowed to a crawl”- had to cut under half rations to lose weight irritable, aggressive, neglectful of hygeine appearance food obsessed during refeeding, most men over ate and gain more than previous normal weight many did not return to previous