NSC 170C1 1st EditionExam 4 Study Guide: Lectures: 20 – 25 29 &30 Lecture 20Calculating BMI ( a calculation of your weight related to your height) : (Weight in pounds/ height in inches ^2 ) X 703Different categories of BMI- Underweight <18.5- Healthy weight 18.5 to 24.9- Overweight 25 to 29.9- Obese ≥30Disease risk based on BMI- Underweight is associated with increased risk of infection and higher overall risk of mortality.- Overweight is associated with increased risk of certain chronic diseases.- Obesity is associated with 50 to 100 percent higher risk of premature deathDetermining % body fat Healthy males (ages 20 to 49) average 16 to 21 percent of weight as body fat. Healthy females (ages 20 to 49) average 22 to 26 percent of weight as body fat. Techniques to measure percentage of body fat include:- Skinfold thickness measurements- Bioelectrical impedance- Dual-energy X-ray absorptiometry (DXA)- Underwater weighing- Air displacementSubcutaneous vs. Visceral fat- Subcutaneous fat is the fat sandwiched between your skin and muscles- Central obesity is due to storing too much visceral fat (surrounding your organs) in the abdomen- Visceral fat releases fatty acids, which travel to the liver and are thought to cause insulin resistance, and increased LDL (bad) and decreased HDL (good) cholesterol.- Visceral fat increases risk for heart disease, hypertension, and diabetesEnergy balance: the state when energy intake and energy expenditure are equalComponents of Energy Expenditure - Estimated Energy expenditure = BMR + PA +TEFChapter 21Health consequences of being overweight- Hypertension, stroke, and heart disease- Gallbladder disease- Type 2 diabetes- Certain cancers- Osteoarthritis- Sleep apneaSatiety: is the sensation that you have had enough to eat. It determines the length of time between eating episodesHunger: is the physical need for nourishment that drives you to consume foodAppetite: the psychological factors that prompt you to eatHow genetics affects body weight- Genetics plays a role in determining body weight- Genetics interacts with your environment to influence your weighta) Differences in the level or functioning of some hormones can influence body weight and appetite.b) Genetically high levels of ghrelin may cause some people to overeat and become obese.c) Individuals genetically prone to being leptin deficient become massively obese.d) May affect how calories are expended by influencing thermogenesis, the production of heat in body cellse) May cause different rates of nonexercise-associated thermogenesisHow environmental factors affect body weight- Environmental stimuli can drive your appetite.a) Aromas, events, people, and the convenience of obtaining food can encourage eating even when you’re not hungry.- Environmental issues are feeding Americans’ energy imbalance.a) We work more and cook less.b) Almost one-third of Americans’ daily calories come from ready-to-eat foods that are prepared outside the home.- Between 1972 and 1995, the prevalence of eating out increased by almost 90 percent.Losing weight healthfully- An energy deficit of 3,500 calories is required to lose a pound of fat.- A deficit of 250 to 500 calories daily will result in weight loss of ½ to 1 pound weekly.- 3 Keys a) Dietb) Physical activityc) Behavior changeBehavior Modification - Behavior modification focuses on changing behaviors that contribute to weight gain or impedeweight lossa) Self-monitor behavior by keeping a food logb) Control environmental cues that trigger eating when not hungryc) Learn how to better manage stress- Table Tips: Adopt Some Healthy Habits1. Don’t eat out of boredom; go for a jog instead.2. Shop with a full stomach and a grocery list.3. When you feel stressed, lace up those sneakers and go for a walk.4. Celebrate without a plate. Replace the traditional restaurant dinner with a no-calorie reward, such as a new music download or the latest best seller.5. Declare a vending machine–free day at least once a week and stop the impulsive snacking.Extreme measures for treating obesity 1. Weight-loss medicationsSibutramine (Meredia): suppresses appetiteOrlistat (Xenical & Alli): inhibits fat absorption2. Gastric bypass surgeryStomach is stapled, leaving a small pouch that can expand to a maximum of 5 ouncesFood leaving the stomach bypasses the upper portion of the small intestine.Can experience deficiencies of vitamin B12, iron, and calcium3. Gastric bandingSilicon band placed around the top of the stomach to create a small pouch with a very narrow openingDelays gastric emptying4. LiposuctionSubcutaneous fat is removed from the abdomen, hips, or thighs.Gastric Bypass and Gastric BandingChapter 22Factors that can lead to underweight- Medical conditions such as cancer or intestinal disorders- Alcoholism- Psychiatric disorders such as depression or dementia- Chronic emotional stress- Poverty- Excessive physical activity- Excessive caloric restriction due to dieting- Unrealistic body images in the mediaHealth consequences of being underweight- Underweight can increase your risk for many health problems, including: Disorders related to nutrient deficiencies such as anemia, hair loss, irregular heartbeat, impaired nerve function, and low bone density- Increased risk for fractures due to low bone density- Reduced immune defenses- Loss of menstrual periods and risk of miscarriage in womenFactors involved in gaining weight healthfullyFactors that contribute to the development of an eating disorder- Sociocultural Factors- Physical Factors- Psychological Factors- Anorexia Results from Severe Calorie Restriction- Bulimia Involves Cycles of Binge Eating and Purging- Binge Eating Disorder Involves Compulsive OvereatingDisordered Eating vs. Eating Disorder- Disordered eating describes a variety of eating patterns considered abnormal and potentially harmful.- Refusing to eat, compulsive eating, binge eating, restrictive eating, vomiting after eating, or abusing diet pills, laxatives, or diureticsIt is possible for someone to engage in disordered eating patterns without having an actual eating disorder- Eating disorders are psychological illnesses that involve specific abnormal eating behaviors: anorexia nervosa (self-starvation) and bulimia nervosa (binging and purging).Binge eating: binge eating disorder involves compulsive overeatingRecurrent episodes of binge eating without purgingEat without regard to physiological cues and may feel out of