Chapter 9 Nutrition, Exercise, and Weight Management Introduction Healthful diet and regular exercise help people live longer, happier, more capable lives. Poor eating habits and lack of exercise exact a great toll: 400,000 deaths a year. Six Groups of Nutrients 1. Carbohydrates 2. Proteins 3. Fats Macronutrients 4. Vitamins 5. Minerals 6. Water Micronutrients Nutrition and Healthful Eating A nutritious diet should include all 6 nutrients, with an emphasis on: • • • • Complex rather than simple carbohydrates Focus on fruits, vegetables, and whole grains Reduced amounts of saturated fat, sodium and sugars Limited (but sufficient) number of daily calories Or, in the words of Michael Pollan: “Eat food. Not too much. Mostly plants.” Nutrition and Healthful Eating Grains (and Starches): Fuel for the Body Eat fewer simple carbohydrates (sugars, white bread, white rice, refined pasta)… …and more (ideally ½ or more of total carbs) of complex carbohydrates (brown rice, whole wheat bread and pasta, oatmeal, etc.) Fruits and Vegetables Almost all Americans could benefit by eating more fruits and vegetables. A good rule of thumb: fruits and vegetables should make up about ½ of a balanced diet. Benefits: low in calories and sodium; contain fiber, vitamins, and minerals; contain little fat (and if they do have fat, it’s usually unsaturated) Proteins Proteins: Providing the building blocks for the body Vary your sources of protein for the most benefit (more seafood and vegetable-based sources of protein; fewer sources of red meat and cheese) Dairy Products • Provide calcium, protein, and other nutrients • Look for low-fat sources: dairy products, like beef and pork, naturally can be high in saturated fats. Fats • An essential part of a nutritious diet* • Unsaturated (liquid at room temperature) fats lower the risk for heart disease • Saturated fats (solid at room temperature) increase the risk for heart disease *Fats are naturally high in calories, so a moderate daily consumption is best. Trans fats: Greatly increase the risk for heart disease Water: Essential for Every Body System • Body = 50% to 70% H2O • Loss of 2% to 5% of the body’s water supply = dehydration Nutrients Vitamins: Organic compounds needed in small amounts • Fat-soluble = A, D, E, K • Water-soluble = B complex, C • Folate (folic acid) • Antioxidants and phytochemicals Minerals: Inorganic compounds needed in small amounts • Macrominerals = calcium, chloride, magnesium, phosphorous, potassium, sodium • Calcium and iron are important to women Nutrition Facts Label Exercise and Fitness Benefits of regular physical activity • Reduces the risk of early death • Reduces risk of developing coronary heart disease, stroke, and breast, lung, and colon cancer • Reduces the risk of developing type 2 diabetes, osteoporosis, and depression • Lowers high blood pressure and cholesterol • Improves aerobic capacity, muscle strength, and muscle endurance Exercise and Fitness • Can reduce symptoms of depression and increase cognitive functioning • For older adults, improves ability to complete day-to-day tasks, reduces the risk of falls, and improves mental cognition • Helps maintain healthy muscles, joints, and bones • Helps control weight, build muscle, and reduce body fat • Can reduce symptoms and severity of diabetes and arthritis • Improves mood and quality of sleep. Exercise and fitness Physical inactivity is a major public health problem in the United States! Most Americans do not get enough physical activity to receive significant benefit. Exercise: How Much Is Needed? • Any physical activity provides some benefits. • Good benefits come with 2.5 hours of moderate-intensity or 1.25 hours of high intensity activity per week. • Greater benefits come from 300 minutes of moderateintensity activity or 150 minutes of high-intensity activity (or more). Components of Physical Fitness • Cardiovascular endurance • Muscular strength • Muscular endurance • Flexibility • Body composition Total Fitness Strength training and aerobic exercise both provide benefits. Together, they complement each other—building muscle mass and strengthening the heart. Gender Gaps: Women vs. Men Physical differences in muscle size • Women are half as strong in upper body areas, two-thirds as strong in lower body and legs • Smaller muscle fiber areas, but individual muscle fibers are the same strength • Higher percentage of body fat • Lower blood volume, smaller hearts, less lung capacity Gender Gaps: Women vs. Men Cultural differences in athleticism and exercise habits • Women traditionally not encouraged to exercise, whereas men are. • Until Title IX, funding for men’s activities dwarfed women’s funding. • Boys are encouraged to excel; girls are taught to fit in. Exercise Myths • Exercise increases the appetite. • Exercising special spots will reduce local areas of fat. • No pain, no gain. • Lifting weights gives women a masculine, bulky physique. • The more sweat produced, the more fat lost. • Exercise is not good for trimming down because weight is gained in muscle. • Women cannot perform well athletically while menstruating. Exercise and Aging • • • • • • • Changes associated with aging that can be prevented or minimized with exercise: Higher body fat Lower lean body weight Decreased muscle strength Decreased flexibility Decreased bone mass Lower metabolism Slower reaction times Exercise Abuse Athletic amenorrhea • Excessive exercise and abnormally low ratio of body fat to body weight stops menstruation Female athlete triad • Disordered eating + amenorrhea + osteoporosis Anabolic steroids • Synthetic derivatives of male hormone testosterone to increase muscle and lean body mass Maintaining a Healthy Weight Weight Gain Influences: Caloric Input > Caloric Output • Genetic • Metabolic Overweight = BMI 25–29.9 • Behavioral • Environmental • Cultural • Socio-Economic Status Obese = BMI >30 Overweight and Obesity • Increasing across age groups, genders, and races • Nearly twice as many overweight children and three times as many overweight adolescents than in 1980 • 65.1% adults are overweight; 4.9% are obese • 16% of U.S. children are overweight; 31% are at risk of soon becoming overweight • Resulting health problems: diabetes, hypertension, coronary heart disease, certain cancers, gout, gallbladder disease, certain arthritic conditions 1985 Obesity in the U.S. 2000 Source: Centers for Disease Control and Prevention. (2011). Behavioral Risk Factor Surveillance System. 1990 2010 Economic Dimensions • Obesity’s annual cost = $150 billion – Direct medical costs: treatment of illnesses – Indirect medical costs: lost productivity, premature disability, early death • Americans spend more than $60 billion a year trying to lose weight. 70 million people are trying to lose weight, and 95% of them are unsuccessful. How Women Can Maintain a Healthy Weight Healthful strategies for weight loss/management • Caloric input < caloric output • Increase BMR via exercise • Balanced, nutritious diet (with all six nutrients consumed daily) • Reasonable goals; aiming for long-term results Unhealthful strategies • Yo-yo dieting • Diet pills • Fad diets • Hunger or starvation • Unrealistic goals; aiming for the short term A few additional words about obesity, overweight and overall health… • “Overweight” does not always mean “unhealthy.” • If you are “overweight,” getting regular exercise, and eating a nutritious diet, you are probably more healthy than a person who weighs less but does not have those healthful habits. Eating Disorders Eating disorders are serious mental illnesses, with distinct signs, symptoms, and effects on the body. The most common eating disorders include: • Anorexia nervosa • Bulimia nervosa • Binge eating disorder (BED) Global Perspectives • Hunger • Malnutrition • Undernutrition • Overnutrition • Protein-energy malnutrition (PEM) • Vitamin A deficiency (VAD) • Iron deficiency • Iodine deficiency disorders (IDD) Discussion What are some ways to improve nutrition, eating habits, and exercise patterns for • You individually? • This class? • This college? • This country?