Transcript lecture 13
Maintaining a Healthful Weight HLTH-120N Lecture 13 Objectives Define healthful weight and successful weight loss Be able to classify case studies as underweight, overweight, and obese with different methods discussed in class Identify the 3 components of energy expenditure Understand factors in society that influence body weight Develop a plan for healthful weight loss or gain Apply new information to your MyDiet Analysis project What is a healthful body weight? Is it determined by “thinness” or muscle mass? Weight Status Classification Underweight Overweight Obese Metabolic Syndrome A cluster of factors increases risk for heart disease, type 2 diabetes, and stroke: Abdominal obesity Triglyceride levels (>150 mg/dL) HDL cholesterol levels (<40 mg/dL in men and 50 mg/dL in women) High blood pressure Fasting blood glucose >100 mg/dL Inflammation Fat Distribution Apple Pear Increased risk for chronic diseases No clear association with chronic disease Men tend to store fat in the abdominal region Women tend to store more fat in the lower body fat increases risk for chronic disease Waist circumference Men: above in. Women: above in. Waist-to-hip ratio Men: waist-to-hip ratio higher than 0.90 Women: waist-to-hip ratio higher than 0.80 Evaluating body weight - BMI BMI (Body Mass Index) ratio of weight to height Normal ______ Over risk for chronic diseases increases Under , risk of premature death increases Calculating BMI Kg/m2 (weight in pounds / inches 2) x 703 Ex: Fred is 5’11” and weighs 221 pounds. Calculate his BMI. Limitations of BMI Evaluating Weight - Body Composition What was Fred’s BMI? He is a weight lifter. His body fat percentage is 9%. Body composition Several Ways to assess Body Composition Methods Bioelectric Impedence Analysis Skin-fold calibers Bod-Pod DEXA Underwater Weighing Body fat percentage Classification Men Women Essential fat 2-4% 10-12% Athlete (best for performance) 6-13% 14-20% Healthful 14-17% 20-24% Acceptable 18-24% 25-31% Obese >25% >32% Case Study Activity 1. Jane is a track athlete, and is very strict with her diet because she has heard lower body fat is associated with faster running. She is 5’2” and weighs 99 pounds. She has 12.5% body fat. What is her BMI? Would you classify her as underweight or a healthful weight? 2. Sam is a sophomore in college. In high school he played basketball and was very active, but since going away to school he has stopped exercising and gained some weight. Sam is 5’11” and weighs 220 pounds. His body fat is 25%. How does his weight classification compared to Fred’s? 3. Emily is 12 years old and is very active. She just went through a growth spurt and is 5’0. She weighs 87 pounds, and her health teacher told her that because of her BMI she is very underweight. Emily is concerned, but already has a hearty appetite. What would you tell her? 4. Harold is 55 years old. He has a job where he is standing most of the day so he thinks that is enough activity. He is 5’8” and weighs 247 pounds. What is his BMI and what are some concerns that go along with it? What is successful weight loss? What should change to achieve a healthful body weight? Energy balance determines body weight When energy intake exceeds expenditure When intake is less than expenditure 1 pound = calories Energy Expenditure Most energy expended to perform basic body functions Total 24-hour expenditure is determined by 3 things: Basal Metabolic Rate (BMR) Energy expended to maintain body functions at rest Largely determined by: weight, height, gender, age Can be increased by Physical Activity Thermic Effect of Food Psychologic, social, cultural factors Tips for successful weight loss Healthful weight change: change in energy intake Regular physical activity – must be ___________ Avoid fad diets Behavior modification techniques Healthy Weight Loss Diets Macronutrient Distribution: Examples: DASH diet, USDA food guide etc. How much should you lose per week? Energy deficit per day: Unhealthy diets for weight loss Low Carbohydrate, High Protein, High Examples: Negative effects: Very low fat diets May contain less than % calories from fat Dr. Dean Ornish’s Program for Reversing Heart Disease and The New Pritikin Program Emphasize carbohydrates and fiber Regular physical activity is key Lowers LDL cholesterol, triglyceride, glucose & insulin, and lowers blood pressure Achieve and Maintain Healthful Weight #1: Foods should be dense Treatment for morbid obesity Low-calorie diet and regular exercise Prescription medications Surgery Vertical banded gastroplasty Gastric Bypass surgery Gastric banding Liposuction Safe weight gain When? BMI of less than Body fat less than kg/m2 % Moderate fat intake Eat 500 to 1,000 extra kcal frequently throughout day Avoid tobacco Protein supplements Include amino acid supplements, protein & creatine, etc. Do not enhance muscle gain differently than whole foods May cause major health problems: Changes in blood cholesterol, mood disturbances, fat gain disease w/ high intake long term