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Weight Management Achieving and Maintaining a Healthful Body Weight 5/9/07 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings What is a Healthful Body Weight? A healthful weight • Is appropriate for your age • Is maintained without constant dieting • Is acceptable to you • Is based on family history of body shape and • weight Promotes good eating habits and allows for regular physical activity Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings What is a Healthful Body Weight? Underweight: having too little body fat to maintain health. Overweight: having a moderate amount of excess body fat. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings What is a Healthful Body Weight? Obese: having an excess of body fat that adversely affects health. Morbid obesity: body weight exceeding 100% of normal, creating a very high risk for serious health complications. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Evaluating Body Weight A person’s actual weight is not the only factor to consider. Determining if a person’s body weight is healthful should include: • Determining the Body Mass Index (BMI) • Measuring body composition • Assessing the pattern of fat distribution Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Evaluating Body Weight Body Mass Index • Expresses the ratio of a person’s weight to the • • square of their height BMI = weight (kg) / height (m)2 BMI values below 18.5 or above 30 have increased risks of health problems Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Mortality risk vs. BMI Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Evaluating Body Weight Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Evaluating Body Weight Body Composition • Measurement of body fat and lean muscle mass • Can be measured by • Underwater weighing • Skinfold measurements • Bioelectric impedance analysis • Near infrared reactance • Bod Pod™ Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Evaluating Body Weight Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Evaluating Body Weight Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Evaluating Body Weight Fat Distribution Pattern • Measured by waist-to-hip ratio and waist • circumference Apple-shaped fat patterning - upper body • Increased risk for chronic diseases • Pear-shaped fat patterning – lower body • No significant increased risk for chronic diseases Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Evaluating Body Weight Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Gaining or Losing Weight Whether a person gains or loses weight depends on • Energy intake vs. energy expenditure • Genetic factors • Childhood weight • Behavioral factors • Social factors Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Energy Balance Energy balance • Occurs when energy intake = energy • • expenditure Energy intake = kcal from food Energy expenditure = energy expended at rest and during physical activity Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Energy Balance Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Energy Balance Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Energy Balance Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Energy Intake Calculating the energy that is in a particular food • Carbohydrate is 4 kcal/g • Protein is 4 kcal/g • Fat is 9 kcal/g • Alcohol is 7 kcal/g 1 cup of quick oatmeal has 142 kcal • 6 grams protein x 4 kcal/gram = 24 kcal • 25 grams carbohydrate x 4 kcal/gm = 100 kcal • 2 grams fat x 9 kcal/gram = 18 kcal • Total kcal = 24 kcal + 100 kcal + 18 kcal = 142 kcal Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Total Energy Expenditure Total energy expenditure = basal metabolic rate (BMR) + thermic effect of food (TEF) + energy expended in physical activity Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Energy Balance Basal Metabolic Rate (BMR) • Energy expended to maintain basal, or resting, • • • functions of the body Basal metabolism is the highest proportion of total energy expenditure More lean tissue increases your BMR BMR decreases with age Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Energy Balance Thermic Effect of Food (TEF) • Energy expended to process food Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Physical activity Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Genetic Factors Genetic factors account for about 25% of a person’s body fat. Different ideas have been suggested to explain the impact of genetics on body fat. • Thrifty Gene Theory • Set-point Theory • Leptin Theory Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Genetic Factors Thrifty Gene Theory • Proposes that a gene (or genes) causes people to • • be energetically thrifty Proposes that people with this gene expend less energy than other people and therefore gain weight A “thrifty gene” has not been identified Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Genetic Factors Set-Point Theory • Proposes that each person’s weight stays within • a small range (set point) The body compensates for changes in energy balance and keeps a person’s weight at their set point Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Physiologic factors •Hunger •Proteins released by body (hormones, peptides) Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Physiologic Factors Leptin • Leptin is a hormone produced by fat cells that • • causes reduced food intake, reduced weight, decreased body fat Leptin is controlled by the ob gene Mutation of the ob gene causes reduced levels of leptin leading to increased food intake and reduced energy output Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Physiologic Factors Ghrelin • Ghrelin is synthesized in stomach, functions as • • a hormone Role in appetite regulation through its actions on the hypothalamus Stimulates appetite, increases amount of food one eats Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Physiologic factors Peptide YY (PYY) • PYY is produced in the gastrointestinal tract • Released after meal in proportional amounts to • • the energy content of the meal. Functions to decrease appetite, decrease food intake May play important role in obesity Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Childhood Factors Environmental factors in childhood can influence • Food choices • Activity levels • Later adult behaviors Childhood overweight increases the risk of heart disease and premature death as an adult. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Behavioral Factors Food Choices The composition of a person’s diet should remain balanced. Hunger vs. Appetite Appetite, a psychological desire to eat, can cause people to overeat. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Social Factors Social factors influencing our diet include: • Family or cultural traditions • Holidays and celebrations • Easy access to high-fat foods • Less physically active lifestyles • Societal expectations of the “perfect” body Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Determining Kilocalorie Needs The most accurate way to determine your energy needs: • Calculate your BMR • BMR = weight (kg) x 1.0 (for men) • BMR = weight (kg) x 0.9 (for women) • Add the energy required to maintain your activity level to your BMR Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Achieve & Maintain Healthful Weight Healthful weight change requires • Gradual change in energy intake • Regular and appropriate physical exercise • Application of behavior modification techniques Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Achieve & Maintain Healthful Weight Effective weight loss should include • Following recommended serving sizes • Reduced intake of high-fat and high-energy • foods Regular physical exercise • To increase energy expenditure • To increase BMR Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Achieve & Maintain Healthful Weight Weight loss medications and herbal supplements: • May have dangerous side effects • Many have been removed from market • Should only be used if a person has • A BMI of 30 kg / m2 • A BMI of 27 kg / m2 and other health risk factors Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Achieve & Maintain Healthful Weight Effective weight gain should include • Eating 500 to 1,000 extra kcal/day • Eating frequently throughout the day • Maintaining a balanced diet, limiting fat intake • • to 15-30% of total energy intake Avoiding tobacco products which depress appetite and increase BMR Regular exercise with resistance training Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Protein supplements •Do not increase muscle growth or strength •Claim to be anabolic (increase muscle mass) • Protein supplements • Androstenedione (affects HDL and LDL negatively) Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Anabolic steroids •Cause major health problems, including: • Unhealthy changes in blood cholesterol • Mood disturbances • Testicular shrinkage in men • Breast enlargment in men • Irreversible clitoral enlargement in women Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Disorders Related to Energy Intake Underweight • BMI below 18.5 kg / m2 • Increases the risk of infections and illness and • can even be fatal Can be just as unhealthy as overweight Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Disorders Related to Energy Intake Overweight • BMI between 25 and 29.9 kg / m2 • Increases the risks of high blood pressure, heart • disease, type 2 diabetes sleep disorders, osteoarthritis, gallstones Can lead to obesity Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Disorders Related to Energy Intake Obesity and Morbid Obesity • Obesity: BMI from 30 to 39.9 kg / m2 • Morbid obesity: weight that exceeds 100% of • • normal 5 of the 9 leading causes of death in the US are associated with obesity A multifactorial disease – many things cause obesity Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Disorders Related to Energy Intake Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Disorders Related to Energy Intake Treatments for obesity may include • Low-calorie diet and regular exercise • Prescription medications • Surgery • Gastroplasty • Gastric bypass • Gastric banding Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Disorders Related to Energy Intake Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Disorders Related to Energy Intake Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Great websites for BMI calculation National Heart, Lung, and Blood Institute: BMI Calculator http://www.nhlbisupport.com/bmi/bmicalc.htm Centers for Disease Control: BMI Calculator and Factors that Affect BMI http://www.cdc.gov/nccdphp/dnpa/bmi/bmi-forage.htm Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings