Ch10 body weight and mgmt


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Essentials of Healthy Living, 6th Edition

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Ch10 body weight and mgmt

  1. 1. Chapter 10 Body Weight and Its Management
  2. 2. Overweight and Obesity • Conditions characterized by excessive and unhealthy amounts of body fat • Result from a complex combination of biological, psychological, environmental, cultural, and socioeconomic factors • Obesity—a chronic metabolic disease that is extremely difficult to treat
  3. 3. Overweight and Obesity (continued) • The majority of adult Americans have too much body fat. • Overweight and obesity are the most common nutritional disorders in the United States. • These conditions often result from a combination of poor diet and lack of physical activity.
  4. 4. Overweight and Obesity (continued) • A healthy body is not fat-free. • Adipose cells store extra energy from food as triglyceride (fat). • As more excess energy is consumed, fat cells continue to store it as fat and increase in size. • Under certain conditions, more fat cells can develop.
  5. 5. Defining Overweight and Obese • Height and weight tables are no longer used to determine whether a person is overweight or obese. • The body mass index (BMI) is used to determine if a person weighs too much. • BMI is a ratio of height to weight. – To calculate BMI, multiply weight (lbs) by 705; then divide the number by height in inches squared.
  6. 6. Body Mass Index – BMIs less than 18.5 are in the underweight range. – BMIs between 18.5 and 24.9 are considered healthy. – BMIs between 25.0 to 29.9 are within the overweight range. – BMIs over 30.0 are in the obese range. – BMIs of 40 or more are referred to as morbid, extreme, or super obese.
  7. 7. Prevalence of Overweight and Obesity • In the United States, the prevalence of excess body fat has reached epidemic proportions. – In 1980, almost 50% of adults were overweight or obese. – By 2006, 2 in 3 of adults were too fat and more than 1 in 3 were obese. • American children are growing fatter, too. • The WHO recognizes obesity as a worldwide health problem (globesity).
  8. 8. Health Risks • Overweight and obese people have higher than average risks of: – Osteoarthritis – Sleep apnea – Gallbladder disease – Carpal tunnel syndrome – Gout – Hypertension – Diabetes – Metabolic syndrome – Heart disease
  9. 9. Health Risks (continued) • Certain cancers: – Colon – Breast (menopausal women) – Uterus – Kidney – Esophagus • Surgery is riskier • Breathing problems
  10. 10. Health Risks (continued) • Fertility problems • Gestational diabetes, hypertension during pregnancy, and giving birth to babies with birth defects • Interference with daily activities like walking, carrying, kneeling, and stooping • Psychological depression, particularly among obese women
  11. 11. The Caloric Cost of Living • The body expends 50% to 70% of calories to fuel vital metabolic activities, including: – Building and repairing tissues – Breathing – Circulating and filtering blood – Producing and transporting substances – Maintaining body temperature
  12. 12. The Caloric Cost of Living (continued) • Factors that influence the metabolic rate include: – Genetics – Hormones • Thyroid hormone • Cortisol** (stress hormone) – Proportion of muscle to fat – Gender – Age – Exercise
  13. 13. The Caloric Cost of Living (continued) • Physical Activity – Calories are needed to move skeletal muscles. • Number of calories used is influenced by: –Type of activity –Duration –Intensity –Size of person
  14. 14. Energy for Physical Activities • The amount of energy needed for physical activity depends on the activity, its duration, and intensity. • Physical activities include: – Sport types of exercise – Movement for daily living – Spontaneous muscular movement • Health experts recommend that adults perform at least 30 minutes of moderate-intensity physical activity daily. • Each day, the typical American expends more energy for physical activities associated with daily living than for sport types of activities.
  15. 15. Caloric Cost of Living: TEF • Energy expended for physical activity and vital energy needs require about 90% of body’s energy use. • After eating a meal, the body needs a small amount of energy to digest, absorb, and process nutrients from food. • Thermic effect of food (TEF) accounts for less than 10% of total energy needs.
  16. 16. Energy Balance • When: – Caloric intake equals caloric output, weight is maintained. – Caloric intake is more than caloric output, weight gain occurs. – Caloric intake is less than caloric output, weight loss occurs. • One pound of fat represents about 3,500 calories.
  17. 17. Body Composition • Healthy adults consist of: – About 60% water – 6% to 22% protein – 3% minerals – Remaining weight is mostly fat • Body fat for healthy adults – About one-half of an average person’s fat is subcutaneous. – “Cellulite” does not exist; it’s the same as other fat.
  18. 18. Estimating Body Fat • Hydrostatic weighing (underwater) – Very reliable but not practical or convenient • Bioelectrical impedance – Uses electrical currents to estimate percentage of fat – Small device needed but can provide accurate estimate
  19. 19. Estimating Body Fat (continued) • Near-Infrared Interactance (“Infrared”) – Infrared light is used to estimate percentage of fat (through biceps muscle of upper arm) – Often underestimates • Dual-Energy X-ray Absorptiometry (DEXA) – Measures fat and bone density – Accurate, but expensive – Requires X-ray technician to perform measurement
  20. 20. Estimating Body Fat (continued) • Skinfold Thicknesses – “Pinch an inch” method – Practical and less costly than above methods – Reliability of measurements can be questionable • Waist Circumference – Determines distribution of fat in abdominal area – Need flexible measuring tape
  21. 21. Estimating Body Fat (continued) • Distribution of fat is a more important risk factor than percentage of fat. – “Apple-shapes” • More fat in the central part of body than below waist • Greater risk of serious health problems – “Pear-shapes” • Have excess body fat below waist • Less risk of serious health problems than when fat is centrally located
  22. 22. Causes of Obesity: Biological Influences • Genetics – Genes code for: • Body frame • Fat distribution • Hormones that regulate appetite and metabolism – Some people have “thrifty metabolisms” that tend to conserve energy as fat.
  23. 23. Causes of Obesity: Biological Influences (continued) – According to the set point theory, the level of body fat is genetically preset. (This is still a theory for a reason) • Hunger is the physiological drive to seek and eat food. • Appetite is the psychological desire to eat specific foods. • Satiety is the feeling that enough food has been eaten to relieve hunger and turn off appetite.
  24. 24. Causes of Obesity: Biological Influences (continued) • The digestive system, brain, and fat cells play important roles in controlling hunger and satiety. • The composition of the diet can affect body weight. • Excess calories from carbohydrate, protein, fat, and alcohol can result in weight gain. –A high-fat diet is associated with overeating and gaining body fat.
  25. 25. Causes of Obesity: Other Influences • A variety of environmental, social, and psychological factors promote overeating. – Portion sizes have increased. – Certain types of restaurants encourage overeating. • Fast food and family-style restaurants often promote “super-sized” portions as bargains. – Advertising makes food look more appealing.
  26. 26. Causes of Obesity: Other Influences (continued) – Food availability and convenience, e.g., pizza delivery 24 hours a day – Tendency to overeat during holidays and family gatherings – Sedentary lifestyles – Moods
  27. 27. Weight Management • Balance food intake with energy expenditure. • Avoid fad diets. – Usually result in temporary weight loss – Promote gimmicks – Often are nutritionally inadequate – Fasting may be dangerous • Increase physical activity. • Change eating and physical activity habits for life.
  28. 28. Role of Physical Activity • Daily exercise helps people lose or maintain weight. • Exercise for at least 30 minutes a day. • Physical activities such as walking, jogging, biking, swimming are recommended; choose enjoyable ones. • People over age 40 should obtain approval of personal physician before beginning a vigorous exercise program.
  29. 29. Other Methods of Weight Control • Surgical methods – Gastric bypass – Liposuction • Medications – Appetite suppressants – Fat absorption reduction (small intestine)
  30. 30. Successful Weight Loss Strategies • Sensible and safe weight loss plans: – Are medically and nutritionally sound. – Include practical ways to engage in physical activity. – Are adaptable to one’s psychological and social needs. – Can be followed for a lifetime.
  31. 31. Successful Weight Loss Strategies (continued) • Set realistic weight loss goals. • Emphasize behavior modification. – Eat nutritiously as well as develop physical activity habits. • Follow the MyPlate guidelines. (bs) • Engage in at least 30 minutes of physical activity daily. • Seek family or other forms of social support. • Include long-term plan for maintaining new weight.
  32. 32. Weight Gain • To gain weight by increasing lean tissue: – Need at least 700–1,000 additional calories per day. (200-400) – Eat three meals per day plus snacks. – No more than 30% calories from fat.(bs!) • Perform muscle-building exercise. • Maintain effort over long term.