NSC 170C1 1st Edition Lecture 21 Outline of Last Lecture I A Healthy Weight What Is It and How Do You Maintain It Outline of Current Lecture I What is overweight II Factors III How to keep a healthy weight A Maintaining Current Lecture I What is overweight and why is it a problem A In the early 1960s fewer than 32 percent of Americans were overweight B Today over 65 percent of Americans are overweight 33 percent are obese i In 2005 obesity was the most frequently covered health story in the media ii Americans spend over 45 billion annually on weight loss solutions iii Medical complications associated with overweight cost the U S health care system 92 billion C Overweight BMI 25 to 29 9 means that a person is as little as 10 to 15 pounds more than a healthy weight D Obesity BMI 30 means a person carries 25 to 40 or more pounds of excess weight E Being overweight can increase risk of i Hypertension stoke and heart disease ii Gallbladder disease iii Type 2 diabetes iv Certain cancers v Osteoarthritis vi Sleep apnea II Factors that contribute to overweight A Hunger and Appetite Affect What and When You Eat i There is a difference between the physiological need for food hunger and the psychological factors that prompt you to eat your appetite ii Hunger is the physical need for nourishment that drives you to consume food iii Satiety is the sensation that you have had enough to eat It determines the length of time between eating episodes a Anything that increases satiety will help decrease weight gain and vice versa B Physiological Mechanisms Help Regulate Hunger and Satiety i Feedback mechanisms involving the mouth stomach intestines and brain work together to increase or decrease your hunger a The hormone Ghrelin produced by the stomach during fasting or between meals stimulates hunger b The hormone Leptin produced by adipose tissue suppresses hunger and food intake ii When food enters your mouth sensory signals are sent to the brain that tell you whether to continue eating iii Distention of the stomach depending on the size of the meal signals the brain to decrease hunger a Also causes release of cholecystokinin a hormone that decreases hunger and helps you feel satisfied iv Once food reaches the small intestine the protein fatty acids and monosaccharaides stimulate feedback to the brain to decrease hunger a Nutrient absorption leads to insulin release which also causes the brain to decrease hunger C Genetics play a role in determining body weight i Differences in the level or functioning of some hormones can influence body weight and appetite a Genetically high levels of ghrelin may cause some people to overeat and become obese ii Individuals genetically prone to being Leptin deficient become massively obese iii May affect how calories are expended by influencing thermogenesis the production of heat in body cells iv May cause different rates of nonexercise associated thermogenesis v Genetic set point may determine body weight a Theory that the body fights to remain at a specific body weight with mechanisms that oppose significant weight loss or gain D Genetics Interacts with your environment to influence your weight i Individuals with a genetic propensity to become overweight experience greater challenges to prevent obesity in an environment conducive to weight gain ii Gene environment interaction a Example High rate of obesity among Pima Indians living in Arizona versus those living in Mexico E Environmental Factors Can Increase Appetite and Decrease Physical Activity i 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 iii Environmental issues are feeding Americans energy imbalance a We work more and cook less 1 Almost one third of Americans daily calories come from ready to eat foods that are prepared outside the home III 2 Between 1972 and 1995 the prevalence of eating out increased by almost 90 percent 3 Dining out frequently is associated with a higher BMI b We eat more and more 1 We have greater access to a wider variety of foods 2 The portion sizes of many foods have doubled or tripled over the past 20 years 3 People tend to eat more when larger portions are served 4 Larger food packaging and serving dishes are also influencing Americans to eat more c We sit more and move less 1 We expend less energy both at work and during leisure time 2 Technology allows us to communicate with coworkers and clients without leaving our desk 3 Labor saving devices such as riding lawnmowers and dishwashers can reduce daily energy expenditure by as much as 100 calories a day 4 More than half of Americans fall short of physical activity recommendations 5 Our leisure and social activities have become more sedentary 6 Over 40 percent of American homes have three or more TVs 7 2 to 18 year olds log more than 5 hours of screen time daily How Can You Lose Weight Healthfully A An energy deficit of 3 500 calories is required to lose a pound of fat i A deficit of 250 to 500 calories daily will result in weight loss of to 1 pound weekly B Health experts agree that a person needs to adjust three areas of life for successful long term weight loss i Diet ii Physical activity iii Behavior change C Three Pieces of the Long Term Weight Loss Puzzle D Eat Smart Because Calories Count i Taking in fewer calories and burning off more will result in weight loss a However cutting back too drastically often results in a failed weight loss attempt ii A key strategy is to eat a healthy balanced diet that is not only lower in calories but also satisfying iii One way to add heft and satiation to lower calorie meals is by including higher volume foods E Eat More Vegetables Fruit and Fiber i High volume low energy density foods fill you up before they fill you out a Fruits and vegetables have a high water content which gives them bulk b Whole grains contain filling fiber c Low in fat and high in carbohydrates ii Research shows these foods are associated with increased satiety and reduced calorie intake and feelings of hunger iii Overweight individuals consume less dietary fiber and fruits than normal weight people F Include Some Protein and Fat in Your Meals i Protein has a dramatic effect on satiety ii Fat also prolongs satiety by slowing the movement of food out of the stomach into the intestines a Including some lean protein and fat in all meals and with snacks can help increase satiety between meals G Use