© 2010 cengage-wadsworth chapter 5 weight management outline: 1.overweight vs. obesity 2.diet...
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© 2010 Cengage-Wadsworth
Chapter 5Weight Management
Outline:1.Overweight vs. Obesity2.Diet Crazes3.Eating Disorders4.The Physiology of Weight Loss5.Diet and Metabolism6.Exercise: The Key to Weight Management7.Losing Weight the Sound and Sensible Way8.Behavior Modification & Adherence to a Weight Management Program9.The Simple Truth
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Weight Management
• Obesity has become an epidemic in most developed countries around the world
• The WHO estimates 35% of the adult population in industrialized nations is obese
• The obesity level is the point at which excess body fat can lead to serious health problems
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Average weight of Americans between 1963-1965 and 1999-2002
• Obesity and overweight have dramatically increased as a direct result of physical inactivity and poor dietary habits
• Average weight of American adults between ages 20 and 74 has increased by 25 lbs. or more since 1965
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1 2 3 4 5 6 7 8 9Percentage of the adult population that is
overweight (BMI ≥ 25) and obese (BMI ≥ 30) in the United States
• More than 66% of U.S. adults are over overweight and 32% are obese
• Between 1960 and 2002, the prevalence of adult obesity increased from about 13% to 30%
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1 2 3 4 5 6 7 8 9Obesity trends in the United States 1985-2007 based
on BMI ≥ 30 or 30 pounds overweight
• Rates of obesity increased in the 1990s
• No state reported an obesity rate above 15% before 1990
• By 2007, only one state had a prevalence of less than 20%
• Thirty states had a prevalence ≥ 25%
• Three of these states had a rate above 30%
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Weight Management
• About 44% of all women and 29% of all men are on a diet at any given moment
• People spend about $40 billion yearly attempting to lose weight– over $10 billion to weight reduction centers
– $30 billion to diet food sales
• About $100 billion spent yearly to treat obesity-related diseases
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Weight Management
• Excessive body weight and physical inactivity are the second leading cause of preventable death in the U.S. (over 112,000 deaths year)
• Obesity is more prevalent than smoking, poverty, and problem drinking
• Obesity and unhealthy lifestyles are the most critical public health problems of the 21st century
• Health risks increase at a BMI over 25 and are enhanced at a BMI over 30
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Health Consequences of Excessive Body Weight
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Overweight versus Obesity
• Overweight: A chronic disease characterized by a body mass index (BMI) greater than 25 but less than 30
• Obesity: A chronic disease characterized by a body mass index (BMI) 30 or higher
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Tolerable Weight
• The media has the greatest influence on people’s perception of what constitutes ideal body weight
• Most people use fashion, fitness, and beauty magazines to determine what they should look like
• The “ideal” body shapes, physiques, and proportions seen in these magazines are rare and essentially achieved only through airbrushing and medical reconstruction
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The Weight Loss Dilemma
• Yo-yo dieting carries as great a health risk as being and remaining overweight
• Data show frequent fluctuations (up or down) in weight increase the risk of dying from cardiovascular disease
• Quick-fix diets should be replaced by a slow, permanent weight loss program
• Individuals gain the benefits of recommended body weight when they reach that weight and stay there throughout life
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The Weight Loss Dilemma
• Only about 10% of people who begin a traditional weight loss program without exercise lose the desired weight
• Only 5 in 100 keep the weight off because the body is highly resistant to permanent weight changes through calorie restrictions alone
• Traditional diets fail because few of them incorporate permanent behavioral changes in food selection and overall increase in physical activity and exercise
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Diet Crazes
• Fad diets continue to appeal to people of all shapes and sizes
• These diets may work for a while but their success is usually short lived
• Fad diets claim that dieters will lose weight by following all instructions
• Very low calorie diets generate a metabolic imbalance by creating a nutritional deficiency
• Much of the weight lost is in the form of water and protein, not fat
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Low-Carb Diets
• Low-carbohydrate/high-protein (LCHP) diets have been very popular– The intake of carbohydrate-rich foods--bread, potatoes, rice, pasta, cereals, crackers, juices, sodas, sweets (candy, cookies, cake), fruits and vegetables--is limited
– Dieters can eat all they want of protein-rich foods including steak, ham, chicken, fish, bacon eggs, nuts, cheese, tofu, high-fat salad dressings, butter, and small amounts of a few fruits and vegetables
• These diets are high in fat• Examples are the Atkins Diet, the Zone, Protein Power, the Carb Addict’s Diet, the South Beach Diet, Sugar Busters
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1 2 3 4 5 6 7 8 9Low-carbohydrate/high-protein diets create nutritional deficiencies and contribute to the
development of cardiovascular disease, cancer, and osteoporosis
• Without fruits, vegetables, whole grains, high-protein diets lack many vitamins, minerals, antioxidants, phytonutrients, and fiber that protect against various ailments and diseases
• Long-term adherence to a LCHP diet may increase one’s risk for heart disease, cancer, and osteoporosis
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Low-Carb Diets
• Side effects associated with LCHP diets include weakness, nausea, bad breath, constipation, irritability, lightheadedness, fatigue
• Your doctor should know if you go on a LCHP diet for longer than a few weeks so that your blood lipids, bone density, and kidney function can be monitored
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Low-Carb Diets
• Adding extra protein (10-15 grams) to a weight loss program can suppress hunger
• Dieters are less hungry when protein intake is increased to 30% of total calories, fat is 20%, and carbohydrates stay at 50% of total calories
• 10-15 grams of protein is equivalent to one and a half ounces of lean meat, two tablespoons of natural peanut butter, eight ounces of plain low-fat yogurt
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Eating Disorders
• Medical illnesses that involve crucial disturbances in eating behaviors thought to stem from some combination of environmental pressures
• Characterized by an intense fear of becoming fat even when the person is losing weight in extreme amounts
• Three most common types are anorexia nervosa, bulimia, and binge-eating disorder
• Emotional eating can also be listed as an eating disorder
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Eating Disorders
• People with eating disorders suffer from family and social problems
• The eating disorder becomes the coping mechanism to avoid dealing with these problems
• Controlling their body weight helps them believe they are restoring some control over their lives
• Eating disorders are common in industrialized nations where society encourages low-calorie diets and thinness
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Eating Disorders
• Most prevalent among people between the ages of 25 and 50
• 40% of college-age women are struggling with an eating disorder
• Every 1 in 10 cases occurs in men• These cases often go unreported because men’s role and body image are viewed differently in our society
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Anorexia Nervosa
• An eating disorder characterized by self-imposed starvation to achieve and maintain very low body weight
• Affects 1% of the population in the U.S.• Anorexics fear weight gain more than death from starvation
• They think of themselves as being fat even when they are emaciated because of their distorted body image
• They are preoccupied with food, meal planning, grocery shopping, and have unusual eating habits
• They will not stop the starvation• They refuse to consider the behavior abnormal
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Anorexia Nervosa
• Physical changes from weight loss and malnutrition include: – amenorrhea (absence of menstruation)
– digestive problems– sensitivity to cold– fluid and electrolyte imbalances (irregular heartbeat)
– injuries to nerves and tendons
– abnormalities of immune function
– anemia– growth of fine body hair
– dry skin– lowered skin/body temperature
– hair and skin problems– mental confusion– inability to concentrate
– lethargy and depression
– osteoporosis
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Anorexia Nervosa
• Diagnostic criteria for anorexia nervosa:– Refusal to maintain body weight over a minimal normal weight for age and height
– Intense fear of gaining weight even though underweight
– Disturbance in perception of one’s body weight, size, or shape; undue influences of body weight or shape on self-evaluation, and denial of seriousness of current low body weight
– Amenorrhea
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Anorexia Nervosa
• The disorder is 100% curable although it has the highest mortality rate of all psychosomatic illnesses--20% die as a result of their condition
• Treatment usually requires professional help• Therapy is a combination of medical and psychological techniques to restore proper nutrition, prevent medical complications, and change the environment or events that triggered the disorder
• It can go undetected because thinness and dieting are socially acceptable
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Bulimia Nervosa
• An eating disorder characterized by a pattern of binge eating and purging in an attempt to lose weight and maintain low body weight
• More prevalent than anorexia nervosa– 1 in every 5 women on college campuses may be bulimic– More prevalent than anorexia in males
• Bulimics are usually healthy looking, well educated, near recommended body weight
• Bulimics enjoy food and often socialize around it• They are emotionally insecure, rely on others,
lack self-confidence and self-esteem• Recommended weight and food are important to them
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Bulimia Nervosa
• The binge-purge cycle can be caused by stress or the compulsion to eat
• Bulimics periodically engage in binge eating that may last an hour or longer during which time they may eat several thousand calories – up to 10,000 calories (in extreme cases)
• After a short period of relief and satisfaction, feelings of deep guilt, shame, an intense fear of gaining weight emerge
• Purging seems to be the easiest answer
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Bulimia Nervosa
• Diagnostic criteria for bulimia nervosa– Recurrent episodes of binge eating characterized by eating in a discrete period of time an amount of food more than most people would eat during a similar period under similar circumstances
– A sense of a lack of control over eating during the episode
– Practice self-induced vomiting, fasting, excessive exercise and misuse laxatives and medications to prevent weight gain
– Binge-purge cycle occurs on average at least twice a week for 3 months
– Self-evaluation influenced by body shape and weight
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Bulimia Nervosa
• Medical problems associated with bulimia include: – cardiac arrhythmias– amenorrhea– kidney and bladder
damage– ulcers– colitis– tearing of esophagus
or stomach– tooth erosion, gum
damage– general muscular
weakness
• Bulimics know their behavior is abnormal and they are ashamed so they practice in secrecy
• A change in attitude can prevent damage or death
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Binge-Eating Disorder
• An eating disorder characterized by uncontrollable episodes of eating excessive amounts of food within a relatively short time
• Most common of the 3 main eating disorders– About 2% of U.S. adults have binge-eating disorder in any 6-month period
– More common in women than in men, 3 women for every 2 men have it
• Depression, anger, sadness, boredom, worry can trigger an episode
• Bingers are usually overweight or obese as bingers do not purge
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Binge-Eating Disorder
• Typical symptoms include:– Eating an unusually large amount of food
– Eating until uncomfortably full– Eating out of control– Eating much faster than usual during binge episodes
– Eating alone due to embarrassment by how much food is consumed
– Feeling disgusted, depressed, or guilty after overeating
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Emotional Eating
• The consumption of large quantities of food to suppress negative emotions
• Emotions include stress, anxiety, uncertainty, guilt, anger, pain, depression, loneliness, sadness, boredom
• People eat for comfort when they are at their weakest point emotionally
• Comfort foods often include calorie-dense, sweet, salty, and fatty foods
• Some foods such as chocolate help to offset negative emotions by causing the body to release mood-elevating opiates
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Emotional Eating
• Eating is a temporary distraction• The following list of suggestions may help:– Learn to differentiate between emotional and physical hunger
– Avoid storing and snacking on unhealthy foods– Keep healthy snacks handy– Use countering techniques (go for a walk instead of eating ice cream, listen to music instead of eating a candy bar)
– Keep a “trigger” log and know what triggers your emotional food consumption
– Work it out with exercise instead of food
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Treatment
• Treatment for eating disorders is available through many schools’ counseling or health center, at local hospitals, community support groups offering confidential help led by professional personnel free of charge
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Energy Balancing Equation
• One pound of fat is the equivalent of 3,500 calories
• In theory, if a person requiring 3,500 calories a day decreased intake by 500 calories per day, the person should lose 1 pound of fat in 7 days (500 x 7 = 3,500)
• When dieters balance caloric input against caloric output, weight loss does not always result as predicted
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Recommendation
• Daily caloric intakes of 1,200-1,500 calories provide the necessary nutrients if they are properly distributed over the basic food groups
• Weight loss should be gradual and not abrupt
• Under no circumstances should a person go on a diet that calls for a level of 1,200 calories or less for women or 1,500 calories or less for men
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1 2 3 4 5 6 7 8 9Body composition changes as a result of frequent dieting
without exercise
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Exercise: The Key to Weight Management
• A person that jogs 3 miles per exercise session 3 times a week burns 900 calories a week; 3,600 calories per month; 46,800 calories per year
• This minimal amount of exercise represents about 13.5 pounds of fat in one year
• Many of the health benefits that people seek by losing weight are reaped through exercise alone
• Exercise offers protection against premature morbidity and mortality for everyone, including people who already have risk factors for disease
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1 2 3 4 5 6 7 8 9Low-Intensity vs. Vigorous-Intensity Exercise for Weight
Loss• A greater proportion of calories burned during low-intensity exercise are derived from fat
• The lower the intensity of exercise, the higher the percentage of fat used as an energy source– During low-intensity exercise, up to 50% of the calories burned may be from fat with the other 50% from glucose
– With intense exercise, only 30%-40% of the caloric expenditure comes from fat
• Overall, twice as many calories can be burned during vigorous-intensity activity, and more fat
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1 2 3 4 5 6 7 8 9Low-Intensity vs. Vigorous-Intensity Exercise for Weight
Loss• If you exercised for 30-40 minutes at moderate
intensity and burned 200 calories, 50% (100 calories) would come from fat
• If you exercised at a vigorous intensity for 30-40 minutes and burned 400 calories, 120-160 calories would come from fat
• Whereas it is true that the percentage of fat used is greater during low-intensity exercise, the overall amount of fat used is still less during low-intensity exercise
• If you exercise at a low intensity, you would have to do so twice as long to burn the same number of calories
• Metabolic rate remains at a slightly higher level longer after vigorous-intensity exercise, so you continue to burn calories after exercise
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Comparison of Energy Expenditure between 30-40 Minutes of Low-Intensity vs. High-Intensity Exercise
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Weight Loss Myths
• Wearing rubberized sweat suits hastens the rate of body fluid that is lost and raises core temperature at the same time– This combination puts a person in danger of dehydration, which impairs cellular function and can cause death
• Mechanical vibrators like vibrating belts and turning rollers are worthless in a weight control program as fat cannot be shaken off
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Losing Weight the Sound and Sensible Way
• Research finds that a negative caloric balance is required to lose weight because: – People often underestimate their intake– People have trouble changing and adjusting to new eating habits
– Many people take a long time to increase their activity level enough to offset the setpoint and burn enough calories to lose body fat
– Most successful dieters monitor their daily caloric intake
– A few people will not alter their food selection, so they must either increase physical activity, have a negative caloric balance, or both
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Caloric Expenditure of Selected Physical Activities
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Losing Weight the Sound and Sensible Way
• Breakfast is a critical meal while you are on a weight loss program
• People who skip breakfast are hungrier later in the day and end up consuming more total daily calories than those who eat breakfast
• Regular breakfast eaters have less of a weight problem, lose weight more effectively, and have less difficulty maintaining weight loss
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Losing Weight the Sound and Sensible Way
• If most of the calories are consumed during one meal, the body may slow the metabolism to store more calories in the form of fat
• Eating most of the calories during one meal causes a person to go hungry the rest of the day, making it difficult to stick to the diet
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1 2 3 4 5 6 7 8 9Behavior Modification & Adherence to a Weight Maintenance Program
• Make a commitment to change• Surround yourself with people who have the same weight loss goals you do as data indicate that obesity can spread through “social networks”
• Gender plays a role in social networks– A male’s weight has a greater effect on the weight of male friends and brothers
– A woman’s weight has a greater effect on sisters and girlfriends
– If you are trying to lose weight choose your friendships carefully
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The Simple Truth
• There is no quick and easy way to achieve and maintain excess body fat loss
• People have to decrease their caloric intake moderately, be physically active, and implement strategies to modify unhealthy eating behaviors
• Three most common reasons for relapse:– Stress-related factors– Social reasons– Self-enticing behaviors
• Making mistakes is human and does not mean failure