Weight Management: Finding a Healthy Balance Chapter 17 - PDF

Weight Management: Finding a Healthy Balance Chapter 17 Sport Books Publisher 1 Introduction  More than 35% of Canadian adults are considered overweight or obese  More than 30% of Canadian children are considered overweight or obese Sport Bo...

Weight Management: Finding a Healthy Balance Chapter 17 Sport Books Publisher 1 Introduction  More than 35% of Canadian adults are considered overweight or obese  More than 30% of Canadian children are considered overweight or obese Sport Books Publisher 2 Introduction  Physical activity has been engineered out of day-to-day life  The food environment has become more “toxic” by the day  Eating disorders have emerged due to social pressures to be thin Sport Books Publisher 3 Energy-Balance Equation Sport Books Publisher 4  Weight Stability  The left side represents Calories consumed  The right side represents Calories expended through physical activity or exercise  This situation depicts a balanced energy equation - a stable weight is achieved Calories consumed = Calories expended Sport Books Publisher 5  Weight Gain  Calories consumed beyond the body’s needs are stored as fat  Weight gain occurs when energy consumed exceeds energy expended through physical activity Calories consumed > Calories expended Sport Books Publisher 6  Weight Loss  Calories expended through physical activity must exceed Calories consumed in food for weight loss to occur Calories consumed < Calories expended Sport Books Publisher 7  Basal Metabolic Rate (BMR): The minimum amount of energy the body requires to carry on all vital functions Sport Books Publisher 8  Basal Metabolic Rate  BMR varies throughout the life cycle  BMR is generally higher at birth and increases until age 2, after which it declines as life progresses  Other factors affecting BMR: Body composition Physical fitness Gender (Males approx. 5% higher) Sleep Pregnancy (20% increase) Body temperature Age Sport Books Publisher 9  Exercise and Weight Management  The amount of energy expended through physical activity depends on: Volume of exercise (time, number of workouts) Intensity of exercise Type of exercise Sport Books Publisher 10  Exercise and Weight Management In order to efficiently lose weight, exercise should be combined with controlled eating patterns that involve Calorie reduction Sport Books Publisher 11  Benefits of Exercise  Strengthens the heart  Improves endurance  Provides a means of managing stress  Helps prevent osteoporosis  Burns Calories  Increases metabolic rate Sport Books Publisher 12 Body Composition Sport Books Publisher 13  Body Composition  Most common method used in body composition analysis is the ‘Two- Component’ model of the body  This model includes: Lean body mass (LBM) Fat body mass Total body fat (TBF) Sport Books Publisher 14  Lean body mass is calculated as follows: LBM = TBM -TBF Lean body mass = Total body mass - Total body fat  TBF is calculated as follows: TBF = TBM x %BODY FAT 100 Sport Books Publisher 15  Fat Body Mass  Can be divided into two types of fat: 1. Storage Fat (SF) 2. Essential Fat (EF) Sport Books Publisher 16  1. Storage Fat  Fat that accumulates as adipose tissue  Serves as an energy reserve  Cushions and protects internal organs  Mainly subcutaneous distribution  Average male storage fat = 12%  Average female storage fat = 15%  Excess fat is associated with numerous health problems Sport Books Publisher 17  2. Essential Fat: Required for normal physiological functioning Present in 1. Bone marrow 2. Heart 3. Lungs 4. Liver 5. Spleen 6. Kidneys 7. Intestines 8. Muscle 9. Central nervous system Sport Books Publisher 18  2. Essential Fat  Comprises about 3% of body weight for the average male  Comprises about 12% of body weight for the average female makes this fat gender specific  Gender-specific essential fat is located in the mammary glands, pelvic region, and is involved in hormone-related functions and pregnancy Sport Books Publisher 19  Measuring Body Fat Direct Indirect Measurement Measurement Sport Books Publisher 20  Measuring Body Fat  Involves grinding up tissue Direct  Measures fat via Measurement chemical analysis  Impractical for living organisms  Used with cadavers to establish norms Sport Books Publisher 21 Measuring Body Fat  Skinfold calipers  Hydrostatic Indirect weighing Measurement  Bod-Pod  Bioelectrical impedance  DEXA Sport Books Publisher 22 Skinfold Calipers Sport Books Publisher 23  Skinfold Calipers  Measures skinfold thickness to predict or estimate total body fat  Based on the assumption that subcutaneous fat is directly related to total body fat  Accuracy is ± 3% when performed correctly Sport Books Publisher 24 Hydrostatic Weighing Sport Books Publisher 25  Hydrostatic Weighing  Determines body density to be used in further equations that calculate percent body fat  Based on Archimedes’ principle of water displacement - an object submerged in water yields a buoyant force equal to the weight of water displaced Sport Books Publisher 26  Hydrostatic Weighing  To calculate body fat, the following measurements are needed: 1. Body weight on land 2. Underwater body weight 3. Water density at the performed temperature 4. Residual lung volume A more accurate measure Sport Books Publisher 27 The Bod-Pod Sport Books Publisher 28  The Bod-Pod  Uses air displacement to calculate body fat percentage  May facilitate measuring large or heavy individuals because it does not involve underwater submersion  Very accurate measure  Very expensive method Sport Books Publisher 29 Bioelectrical Impedance (BIA)  Based on differences in electrical conductivity between lean mass (fat-free mass) and fat mass Sport Books Publisher 30 Bioelectrical Impedance (BIA)  Percent body fat is calculated from measures of body density determined by passing an electrical current through the body Sport Books Publisher 31 Bioelectrical Impedance (BIA)  BIA is influenced by the subject’s hydration level  The more hydrated one is, the leaner the BIA measurement will be Sport Books Publisher 32 Dual Energy X-Ray Absorptiometry (DEXA) Sport Books Publisher 33  Dual Energy X-Ray Absorptiometry (DEXA)  Can be used to determine body composition  Can also measure bone density (bone mineral content) Sport Books Publisher 34  Body Mass Index (BMI)  Can be used as an easy, inexpensive method for determining an individual’s healthy body weight  Considers weight (kg) and height (m) BMI = Weight (kg) [Height (m)]2  A BMI nomogram can also be used to determine BMI, it looks like this… Sport Books Publisher 35 Body Mass Index (BMI) Sport Books Publisher 36  Body Mass Index (BMI)  Three general ranges: 1. Underweight 2. Healthy or Acceptable Weight 3. Overweight Severe Overweight Morbid Obesity  BMI score > 30 is classified as obese and associated with an increased risk of developing health problems  Note: the risk of developing health problems is also associated with BMI’s classified as being within the underweight range Sport Books Publisher 37  Body Mass Index (BMI)  The BMI is intended for average men and women aged 20-65  It is not intended for: 1. Babies 2. Children 3. Teenagers 4. Pregnant women 5. Very muscular people, such as athletes Sport Books Publisher 38