NSC 170C1 1st Edition Lecture 20 Outline of Last Lecture I. Alcohol Outline of Current Lecture II. Healthy Body WeightA. Body mass index B. Energy balance Current LectureI. Healthy Body WeightA. Healthy Body Weight: a body weight that doesn’t increase the risk of developing weight-related health problems or diseasei. A range appropriate for younger gender, height, and muscle massii. A realistic weight you can maintain naturally by regular exercise and consuming a nourishing dietiii. Weight management: maintaining your weight within a healthy rangeII. Body mass index (BMI): a calculation of your weight in relation to your weight A. Under weight is associated with increased risk of infection and higher overall risk of mortality B. Obesity is associated with 50 to 100 percent higher risk of premature death i. Not a direct measurement of percent body fat and doesn’t asses if weight is predominantly muscle of fat ii. Athletes and individuals with high muscle mass may have a low percentage of body fatiii. Chronic weight loss in older adults may cause low BMI and in individuals less than 5 ft will have a high BMI but doesn’t necessarily mean unhealthy III. Your body fat locationA. Storing excess fat around the waist versus the hips and thighs is shown to increase risk of heart disease, diabetes, and hypertensionB. Central diabetes: is due to storing too much visceral fat in the abdomeni. Subcutaneous fat is the fat sandwiched between your skin and muscles ii. Waist is a quick indicator of unhealthy fatC. Waist-to-hip ratioD. Health risk: visceral fat releases fatty acids which travel to the liver and are thought to cause insulin resistance, and increases LDL and decreasedHDL cholesterol E. Healthy males: average 16 to 21 percent of weight as body fatF. Healthy females average 22 to 26 percent weight as body fatG. Techniques to measure percentage of body fat include:Skinfold thickness measurements Bioelectrical impedance Dual-energy X-ray absorptiometry (DNA) Underwater weighing Air displacement Energy Balance A. Energy balance: the state when energy intake and energy expenditure are equal i. Positive energy balance: when you consume more calories than you expend; causes storage of body fatii. Negative energy balance: when calories intake falls short of needs, body breaks down stored fat for fuelB. You determine if you are in positive or negative energy balance by comparing your caloric intake with your energy expenditure BMR- 50-70% Physical activity- 20-35% TEF 10%C. Your BMR will increase your energy needs i. Basal metabolism is the amount of energy expended to meet the basic physiological needs that enable organs and cells to function; also referred to as basal metabolic rate (BMR) ii. Lean body mass is the factor that most affects BMRiii. BMR is also affected by age, gender, body size, genes, ethnicity, emotional and physical stress, thyroid hormones, nutritional state, environmental temperature, and caffeine and nicotine intake.D. BMR contribution %Liver -29Brain -19Heart -19Kidney -7Skeletal muscle- 18The rest- 17Total 100% Physical activity will increase your energy needsi. Physical activity will increase your energy needs. ii. For very physically active individuals, the amount of energy expended in physical activity can double their BMR.iii. The more physical activity you routinely incorporate, the more calories you will need to meet your energy needs.IV. Calculating your energy “out” (EEE)A. BMR formula (wt in kg)Males 10-18(17.5 x wt) + 65118-30(15.3 x wt) + 67930-60(11.6 x wt) + 879 >60 (13.5 x wt) + 487Women10-18 (12.2 x wt) +74618-30 (14.7 x wt) + 49630-60 ( 8.7 x wt) + 829 >60 (10.5 x wt) +596(Lbs / 2.2 = wt in kg)Physical Activity Level Range Men WomenLight 0.1-0.3 0.1-0.25(walking to class; rec center 1-2x/week 1 hr each visit)Moderate 0.3-0.50 0.25-0.40(rec center 3-5x/week 1.5 hr each visit)Medium Heavy 0.5-0.7 0.4-0.6(rec center 5-7x/week 2 hrs each visit)Heavy 0.7-0.90 0.6-0.80(athlete who works out 3+ hours per day)BMR X Activity = kcals burned by Physical ActivityB. What’s Your Estimated Energy Expenditure?i. Mike, 18 years old, 160 lbs, Works out 4 days per week on average at Rec Center, Range = 0.3-0.5 for Malesii. He eats on average 3,300 kcalsiii. 160/2.2 = 72.7 kgiv. Estimated Energy expenditure = BMR + PA +TEFv. BMR = (15.3 x 72.7) + 679 = (1112.3 + 679) = 1791.3 kcalsvi. Physical Activity = BMR x 0.4 = 1791.3 X 0.4 = 716.5 kcalsvii. Thermic Effect of Food = 10% kcal intakeviii. .10 x 3,300 = 330 kcalsix. Estimated Energy Expenditure = 1791.3 + 716.5 + 330, = 2837.8x. Round to whole numbers EEE = 2838V. What are the Effects of an Energy Imbalance?A. Mike consumes on average 3,300 kcals B. Mikes estimated energy expenditure is 2838C. In= 300, out=2838D. Too Few Calories Can Cause Underweighti. If you consume fewer calories than you need on a daily basis, your body will draw on energy stores to make up the deficit.ii. Glycogen and fat will be used as fuel to meet energy needs until the next time you eat.iii. Amino acids from the breakdown of body protein, particularly muscle, can be used to make glucose.E. If you continue in negative energy balance over time, you will lose weight.F. Too Many Calories Can Cause OverweightG. Eating more calories than you need, regardless of the food source, will result in the body storing the excess as fat.H. Your body has an unlimited capacity to store