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This 6 page Class Notes was uploaded by Emma Trokel on Sunday February 28, 2016. The Class Notes belongs to 2420-001 at University of Colorado at Boulder taught by S. Nelson in Spring 2016. Since its upload, it has received 22 views. For similar materials see Nutrition and Health Performance in Psychlogy at University of Colorado at Boulder.
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Date Created: 02/28/16
Week 7 Chapter 10 Energy Balance What are Overweight and Obesity? ● Overweight having extra weight from bone, muscle, body fat, and/or body water ● Obesity condition characterized by excessive and unhealthy amounts of body fat ○ Widespread nutritional disorders in the U.S. ● In 20092010 ○ 69% of American adults were either overweight or obese Body Composition ● Two major components: ○ Fatfree mass: ■ body water, mineralrich tissues, and proteinrich tissues ○ Total body fat: ■ Adipose tissue ■ Essential fat in cell membranes, certain bones, and nervous tissue Energy Output ● Energy output or expenditure: ○ What energy cells use to carry out activities ● Output includes energy for: ○ Basal and resting metabolism the amount of calories you need to stay alive (Basal) what you burn while sitting and breathing ○ Physical Activity ○ Thermic effect of food (TEF) ○ Nonexercise activity thermogenesis (NEAT) Basal and Resting Metabolism ● Metabolism: ○ Sum of all chemical changes or reactions that constantly occur in living ■ Anabolic (building) reactions require energy ■ Catabolic (breaking down) reactions release energy ● Basal metabolism: ○ Minimal number of calories used for vital physiological activities after fasting and resting for 12 hours Factors that Influence Metabolic Rate ● thyroid hormone (if not producing enough then metabolic rate slows it down) ● body composition ( ● sex (taller people burn more calories than shorter aka male) ● body surface area ^ ● age (goes down as get older) ● calorie intake ● fever (goes up) ● stimulant drugs (speed metabolism) ● pregnancy and lactation (raises metabolic rate, body requires up to 500 more calories a day) ● recovery after exercise (increase) Other uses of Energy ● Thermic Effect of Food (TEF): ○ Energy used to digest foods and beverages, and absorb and process the nutrients ○ Typically 5 to 10% of total caloric intake ● Nonexercise Activity Thermogenesis (NEAT) ○ Energy spent on involuntary skeletal muscle activity such as fidgeting, shivering, and maintaining muscle tone or body posture ○ Some people may expend as much as 700 kcal/day from NEAT Adipose Tissue ● All cells contain some lipids, but adipose cells store a droplet of fat ○ Overeating can cause an increase in fat cell size and number ● Scientists think that once fat cells are formed, the remain, unless they die or are surgically removed Subcutaneous Fat and Visceral Fat ● Subcutaneous fat: ○ sub = under cutaneous = skin ○ Helps insulate ○ Protect muscles and bones from injury ● Visceral fat: ○ Forms protective structure under abdominal muscles and over stomach and intestines Lower Body Fat: ● “Pear Shape” adds stress to hip and knee joints, but carries lower risk of chronic diseases such as type 2 diabetes Central Body Fat: ● “Apple Shape” poses higher risk or serious health problems Measuring Waist Circumference ● Waist circumference is a quick and easy way to determine obesity related risk ● Desirable circumferences: ○ men < 40 inches ○ Women < 35 inches Body Fat Distribution: Effects on Health ● Distribution of excess body fat is more closely associated with obesityrelated diseases than the percentage of total body fat ● Centralbody obesity is characterized by excessive abdominal (visceral fat) ● Central obesity is associated with increased risk for cardiovascular disease and type 2 diabetes How Can I Calculate My BMI? ● What is BMI? ○ Numerical value of relationship between body weight and risk of certain chronic health problems ● Simple Formula: ○ weight (lbs) divided by height (in)^2 x 703 Adult Weight Status Categories (BMI) ● Below 18.5 underweight ● 18.524.9 healthy ● 25.029.9 Overweight ● 30.039.9 Obese Measuring Body Fat ● Underwater Weighing ○ Compares weight on land to weight when completely submerged in a tank of water ● Problems: ○ inconvenient, expensive, and impractical Dualenergy x ray absorptiometry (DXA) ● Uses multiple lowenergy xrays to scan body: ○ Provides detailed “picture” of internal structures ○ Problems: very expensive and not widely available outside of clinical settings Air Displacement ● Assesses body volume ● Subject sits in BOD POD chamber ● Volume of air in chamber with a person in it is compared to a volume without the person in it Bioelectrical Impedance ● Measures conduction of a weak electrical current through the body ● Problems: ○ Method can be reliable if body hydration status is normal ○ Scientific data about accuracy of devices designed for home use are lacking Skinfold Thickness ● Skinfold Thickness is measured at multiple body sites by a trained person ● Benefits: relatively easy and inexpensive to perform ● Problems: may underestimate total body fat on overfat people What Causes Overweight and Obesity? ● Physiological aspects ● Environmental influences ● Behavioral factors ● Psychological forces Physiological Factors ● Hunger vs. Satiety: ○ Hunger: uncomfortable feeling leading to a desire to eat ○ Satiety: sense that enough food was eaten ● Proteins that regulate hunger: ○ Ghrelin hormone, secreted mainly by stomach, that stimulates eating behavior ○ Leptin hormone, secreted by adipose cells , that reduces hunger and inhibits fat storage in the body ○ CCK hormone secreted by small intestine that reduces hunger ○ PYY peptide secreted by intestines that reduces hunger Genetic Factors ● Inherited characteristics that influence weight include: ○ Metabolic rate ■ “thrifty metabolism” ○ Hormone production ○ Body frame size ○ Pattern of fat distribution ● What is the setpoint theory? ○ Scientific notion that body fat content is genetically predetermined Environmental Influences ● Appetite: ○ the desire to eat appealing foods ● Hunger: physiological signals ● Environmental influences include: ○ food advertising ○ increased portion sizes ○ conditions that reduce a person’s physical activity Genes and Environment ● Children’s body weights are similar to the weights of their parents ● Which has a greater influence: genes or the environment? ● Environment and other factors can modify gene expression (epigenetics) Other Factors that Influence Weight ● Mood ● Selfesteem ● Emotions ● Societal Pressure Key Factors of Successful Weight Management ● Motivation ● Calorie intake reduction ● Regular physical activity ● Behavior modification Motivation ● Motivating factors include: ○ Recognition of need to change ○ Weight loss “triggers” ○ Medical recommendation to lose weight Calorie Intake Reduction ● Loss of 1 lb body fat requires a negative energy state of 3500 kcal ● To lose 1 lb in 7 days: ○ Reduce caloric intake by 500 kcal per day ○ Expend 500 more kcal per day ○ OR combine eating fewer calories and exercising more to result in a deficit of 3500 kcal ● Regular Physical activity ○ by increasing activity, dieters do not need to limit kcal intake as much Behavior Modification ● Analyze behaviors to identify cues and “problem” behaviors ○ cues are environmental factors that stimulate eating behavior, such as viewing food commercials ● Develop ways to change negative foodrelated and/or physical activityrelated behaviors Tips for Modifying Food and Exercise Related Behaviors ● Planning menus ● Grocery shopping ● Food preparation ● Eating Behaviors ● Holidays and parties ● Restaurants ● Physical Activity ● Self monitoring ● Rewards for new behaviors ● Changing negative thought pattern
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