Weight Management: Finding a Healthy Balance Chapter 12 Sport Books Publisher

Objectives To discuss the differences between overweight and obesity and implications for health To present the concept of caloric balance in weight control To examine the role of exercise and lifestyle modification in maintaining a healthy weight To gain familiarity with the consequences of dieting and eating disorders To set and evaluate personal goals for maintaining a healthy weight Sport Books Publisher

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

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

Energy-Balance Equation Sport Books Publisher

Energy-Balance Equation Body weight is influenced by: Energy expended through physical activity Energy gained through dietary intake Energy is measured in the form of Calories This is expressed by the ‘energy-balance equation’ Sport Books Publisher

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

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

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

Energy-Balance Equation Some people want to put on a few pounds to look better, or to “bulk up” for athletic events Healthy weight gain is best achieved through a regimen of increasing (healthy) food intake while participating in a strength-training program to develop lean muscle tissue Sport Books Publisher

Energy Needs of the Body A large amount of energy must be consumed by the body in order to carry out vital functions such as: Blood circulation Respiration Brain activity Sport Books Publisher

Basal Metabolic Rate (BMR): The minimum amount of energy the body requires to carry on all vital functions Sport Books Publisher

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 Sex Sleep Pregnancy Body temperature Age Sport Books Publisher

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

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

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

Benefits of Exercise Weight management is easier when an exercise regimen is included Greater lean muscle mass, decreased fat mass, and a higher level of fitness are associated with higher levels of metabolism A higher metabolic rate allows you to eat more without gaining weight Sport Books Publisher

Body Composition Sport Books Publisher

Body Composition There are three interrelated aspects of the human physique: Size (volume, mass, surface area, length) Structure (skeletal, muscular, fat arrangement and distribution) Composition (amount of fat, muscle, bone) Body composition is one of the major components of physical fitness Sport Books Publisher

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

Lean Body Mass Refers to the ‘non-fat’ or ‘fat-free’ component of the body Includes skeletal muscle, bone, water May represent a biological lower limit beyond which health is compromised Excessive leanness may increase a female’s chances of developing amenorrhea (absence of menstruation) Amenorrhea includes a reduced production of estrogen, which may also increase a female’s chances of developing osteoporosis Sport Books Publisher

LBM = TBM -TBF Lean body mass = Total body mass - Total body fat 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

Can be divided into two types of fat: Storage Fat (SF) Fat Body Mass Can be divided into two types of fat: Storage Fat (SF) Essential Fat (EF) Sport Books Publisher

Fat that accumulates as adipose tissue 1. Storage Fat Fat that accumulates as adipose tissue Sport Books Publisher

Serves as an energy reserve 1. Storage Fat Serves as an energy reserve Sport Books Publisher

Cushions and protects internal organs 1. Storage Fat Cushions and protects internal organs Sport Books Publisher

Mainly subcutaneous distribution 1. Storage Fat Mainly subcutaneous distribution Sport Books Publisher

Average male storage fat = 12% Sport Books Publisher

Average female storage fat = 15% Sport Books Publisher

Excess fat is associated with numerous health problems 1. Storage Fat Excess fat is associated with numerous health problems Sport Books Publisher

Required for normal physiological functioning 2. Essential Fat Required for normal physiological functioning Sport Books Publisher

2. Essential Fat Present in Bone marrow Heart Lungs Liver Spleen Kidneys Intestines Muscle Central nervous system Sport Books Publisher

Comprises about 3% of body weight for the average male 2. Essential Fat Comprises about 3% of body weight for the average male Sport Books Publisher

Comprises about 12% of body weight for the average female 2. Essential Fat Comprises about 12% of body weight for the average female Sport Books Publisher

2. Essential Fat Gender-specific essential fat is located in the mammary glands, pelvic region, and is involved in hormone-related functions and pregnancy Sport Books Publisher

Measuring Body Fat Direct Measurement Indirect Measurement Sport Books Publisher

Measuring Body Fat Involves grinding tissue Measures fat via chemical analysis Impractical for living organisms Used on cadavers Direct Measurement Sport Books Publisher

Measuring Body Fat Skinfold calipers Hydrostatic weighing Bod-Pod Bioelectrical impedance DEXA Indirect Measurement Sport Books Publisher

Skinfold Calipers Sport Books Publisher

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

Hydrostatic Weighing Sport Books Publisher

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

Hydrostatic Weighing Bone and muscle have a greater density than water Fat is less dense than water Thus, a person’s relative buoyancy is positively correlated with body fat That is, a person with a higher body fat percentage is less dense (weighs less in water) than a lean individual Sport Books Publisher

Hydrostatic Weighing To calculate body fat, the following measurements are needed: Body weight on land Underwater body weight Water density at the performed temperature Residual lung volume More accurate measure Sport Books Publisher

The Bod-Pod Sport Books Publisher

The Bod-Pod Very expensive method Very accurate measure May facilitate measuring large or heavy individuals because it does not involve underwater submersion Sport Books Publisher

Bioelectrical Impedance (BIA) Sport Books Publisher

Bioelectrical Impedance (BIA) Based on differences in electrical conductivity between fat-free mass and fat mass Sport Books Publisher

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

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

Dual Energy X-Ray Absorptiometry (DEXA) Sport Books Publisher

Dual Energy X-Ray Absorptiometry (DEXA) Can be used to determine body composition Can also measure bone density (bone mineral content) Sport Books Publisher

BMI = Weight (kg) [Height (m)]2 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

Body Mass Index (BMI) Sport Books Publisher

Body Mass Index (BMI) Three general ranges: Underweight Healthy or Acceptable Weight Overweight Severe Overweight Morbid Obesity BMI score > 30 is classified as obese and associated with an increased risk of developing health problems Risk of developing health problems is also associated with BMI’s classified as being within the underweight range Sport Books Publisher

Body Mass Index (BMI) The BMI is intended for men and women aged 20-65 It is not intended for: Babies Children Teenagers Pregnant women Very muscular people, such as athletes Sport Books Publisher

Somatotyping The human body is composed of: Roundness Muscularity Linearity Various sports require sport-specific body types for achieving optimal performance Sport Books Publisher

Somatotyping Endomorphs exhibit a round appearance and a predominance of the gut and visceral organs Common sports that require this body type include wrestling, weight-lifting, and throwing events Sport Books Publisher

Somatotyping Mesomorphs exhibit a predominance of muscle Common sports that require this body type include body building, swimming, and decathlon Sport Books Publisher

Somatotyping Ectomorphs exhibit a predominance of linearity and tend to be tall and thin Common sports that require this body type include marathon, basketball, horse-racing, and high-jump Sport Books Publisher

Obesity Sport Books Publisher

Having an excess of body fat beyond some particular standard Obesity Having an excess of body fat beyond some particular standard Sport Books Publisher

Obesity To be classified as obese (ages 17-50yrs): Body fat percentage > 20% for males Body fat percentage > 30% for females Obesity has reached epidemic proportions in the Western world 35% of Canadian men and 27% of Canadian women are considered obese Sport Books Publisher

Obesity Environmental Social Psychological Genetic Involves many factors: Environmental Social Psychological Genetic Sport Books Publisher

Obesity Coronary heart disease Stroke Hypertension Diabetes There are numerous health problems associated with obesity, including: Coronary heart disease Stroke Hypertension Diabetes Osteoarthritis Some cancers Sport Books Publisher

Creeping Obesity Obese individuals are often viewed as gluttonous They generally do NOT consume large amounts of calories Physically active individuals have been shown to consume more calories than obese individuals Sport Books Publisher

Creeping Obesity Obesity is often the result of too little activity rather than overeating This is what leads to ‘creeping obesity’ Creeping obesity is the result of a long-term change in energy balance that results in gradual fat gain over a period of time Sport Books Publisher

Misleading Norms Weight norms must be interpreted with caution Overweight does not necessarily mean obese Body composition is important when making this distinction Being ‘overweight’ because of a large lean mass is not associated with the health problems linked to obesity Sport Books Publisher

Weight-Loss Industry Has become a billion-dollar industry as obesity rates rise Many fad diets exist such as High-protein, low-carbohydrate diets High-carbohydrate, low-protein diets Limited food choice diets Most of these diets are ineffective and CAN BE HARMFUL Sport Books Publisher

Weight-Loss Industry Following Canada’s Food Guide and engaging in regular physical activity appears to be the best approach to weight management Sport Books Publisher

Consequences of Dieting Cultural pressures to be thin and the stigma of being overweight have resulted in many young people engaging in dieting and abnormal eating behaviours Sport Books Publisher

Consequences of Dieting Chronic dieting can lead to: Retardation of physical growth Menstrual irregularities in females Lowered metabolic rate Development of eating disorders Sport Books Publisher

Eating Disorders Sport Books Publisher

Eating Disorders Two major eating disorders within the general population: Anorexia Nervosa Bulimia Nervosa A related syndrome is known as ‘Binge Eating Disorder’ (BED) Eating disorders also occur in male and female athletes Sport Books Publisher

Eating Disorders Dissatisfaction with body image Factors involved in the development of eating disorders include: Dissatisfaction with body image Distortions in thinking Perfectionist beliefs Excessive self-criticism Fear of fat Excessive dieting Preoccupation with food Sport Books Publisher

Anorexia Nervosa Failing to eat an adequate amount of food to maintain a reasonable body weight Avoidance of food Engaging in excessive vigorous exercise Sport Books Publisher

Anorexia Nervosa Symptoms Typically, weigh less than 85% of normal weight Dry skin Amenorrhea Reduced bone mass Brittle nails Carotene pigmentation (yellowish appearance of the palms and soles of the feet) Sport Books Publisher

Bulimia Nervosa Characterized by continual episodes of binge eating followed by purging A binge involves eating large amounts of food in a discrete period of time After a binge, vomiting is induced and/or laxatives are used May also involve excessive exercise as a form of purging Sport Books Publisher

Bulimia Nervosa Symptoms Body weight is often normal Secretive eating patterns Nervous or agitated behaviour immediately after eating Loss or gain of extreme amounts of weight Sport Books Publisher

Binge Eating Disorder (BED) Involves ingesting large amounts of food without purging Is encouraged in some sports such as sumo wrestling and football Leads to obesity in most cases Sport Books Publisher

Eating Disorders Among Athletes Athletes competing in sports with weight classes try to “make weight” in lower weight classes to gain a competitive edge Often stems from a performance objectives rather than issues of self-esteem or body image Sports include wrestling, horse racing (jockey), rowing, boxing, weight-lifting, etc. Sport Books Publisher