Managing Your Weight

Chapter 10 Managing Your Weight Learning Outcomes: Describe the relationship between calories and weight Explain theories and evidence as to why people become overweight Discuss the eating disorders, their origins, and their treatment

A Nation at Risk 2 out of 3 adults in the United States are overweight. Over ½ of those overweight are obese Obesity is a major risk factor for many serious health problems including cardiovascular disease, diabetes, respiratory illnesses, and some forms of cancer. Life expectancy is shortened by 6-7 years

Calories and Weight: A Balancing Act Energy In – food energy (calories) we consume Energy Out – energy expended Maintaining normal body functions Digestion, breathing, circulation Through physical activity and exercise

Energy Expended Metabolic Rates – how fast we burn calories Basal Metabolic Rate (BMR) the minimum amount of energy needed to maintain body functions apart from digestion Resting Metabolic Rate (RMR) The minimum energy that the body requires to maintain body functions including digestion Factors affecting metabolic rates: Age Gender Weight Activity Level

Weight Indices BMI (body mass index) Body Composition Broad stroke measure - Based on height/weight BMI 18.5 to 24.9 considered healthy range Does not take age, gender, or lean body mass into account Body Composition More precise measure of body fat% Obese standards >24% males >33% females Waist Circumference, Waist-to-Hip Ratio Men >40”, ratio>1; Women >35”, ratio>0.8 may be at higher health risk

Factors in Becoming Overweight Heredity Genetic contribution to body shape, regulation of the production of leptin – “signals fullness” Metabolic Factors Set point theory: brain regulates “predetermined weight” – thermostat analogy Set point doesn’t lower with dieting alone, need physical activity including muscle fitness Muscle tissue - higher metabolic rate than fat, even at rest

Factors in Becoming Overweight Fat Cells Obese people have billions more fat cells than people of average rate Heredity affects initial number of fat cells, but early dietary habits contribute as well Fat cells are not shed when losing weight, continue to send signals to hypothalamus Women have higher percentage of essential fat then men; makes it easier for men to keep excess weight off

Factors in Becoming Overweight Physical Inactivity Inactivity contributes to weight gain and people tend to be less active as they gain weight Problem Eating Habits Eating fast – it takes the brain 15 minutes to catch up with the stomach Fast Food Food–Related Cues Emotional Eating Celebrations, “drown our sorrows”

Eating Disorders Characterized by persistent, gross disturbances in eating patterns More than ½ of teenage girls and nearly 1/3 of teenage boys use unhealthful methods to try and control weight including fasting, skipping meals, smoking, purging by vomiting or laxatives Incidences of eating disorders has increased markedly in recent years. Afflicts mainly women during adolescence and young adulthood Women tend to be perfectionists about their bodies

Eating Disorders Anorexia Nervosa characterized by the maintenance of an unusually low and unhealthy body weight and accompanied by an intense fear of gaining weight, a distorted body image, and in females, an absence of menstruation Females can drop 25% or more of their weight within a year triggering abnormalities and health problems Common trigger seems to be onset of puberty and corresponding weight gain

Eating Disorders Bulimia Nervosa Characterized by repeated episodes of binge eating followed by purging, and accompanied by persistent fears of gaining weight Various methods of purging: vomiting, use of laxatives, strict dieting or fasting, prolonged demanding exercise regimens Triggers hormonal imbalances

Origins of Eating Disorders Different explanations may symbolize a young woman’s efforts to cope with sexual fears Dysfunctional families Starts as form of rebellion against parents who are obsessed with getting their children to eat History of child abuse – higher risk Social-cultural factors – slimness is idealized Involvement in activities with weight limits Genetic factors – personality traits

Treatment for Eating Disorders Those who become dangerously thin or malnourished are hospitalized and force-fed if necessary. Use of drugs that curb the actions of serotonin Antidepressants Psychological approaches Behavior modification Response prevention Psychodynamic treatment Family therapy