Chapter 8: Body Composition and Weight Control Exercise Physiology for Health, Fitness, and Performance Fifth Edition Chapter 8: Body Composition and Weight Control Denise L. Smith • Sharon A. Plowman

I. The Caloric Balance Equation Kilocalorie—The amount of heat needed to raise the temperature of 1 kg of water by 1°C Caloric Balance Equation—The mathematical summation of the caloric intake (+) and energy expenditure (−) from all sources

I. The Caloric Balance Equation (cont.) + food ingested (kcal) − basal or resting metabolic rate (kcal) − thermogenesis (kcal) − work or exercise metabolism (kcal) − energy excreted in waste products (kcal)

Caloric Balance

Energy Expenditure

Appetite Control

The next section details the effect of 1) diet, 2) exercise, and 3) exercise training on the components of the caloric balance equation: A. Food intake (kcal) B. Basal or resting metabolic rate (kcal) C. Thermogenesis (kcal) D. Work or exercise metabolism (kcal) E. Energy excreted in waste products (kcal)

Overview of How Section Is Organized Components of Caloric Balance Equation Diet Exercise (acute) Exercise Training Food Intake BMR Thermogenesis Exercise/activity/work energy expenditure Energy expended in waste

Food Intake Impact of diet on food intake Impact of exercise on appetite and food intake No clear evidence for a transient reduction or increase in food intake following exercise bout

Food Intake (cont.) Impact of exercise training on appetite and food intake Active individuals consume more calories than sedentary individuals Energy intake increases (highly trained and lean) or remains unchanged as a result of training (untrained and obese) When training ceases, energy intake is spontaneously reduced

Resting or Basal Metabolism Basal Metabolic Rate—The level of energy required to sustain the body’s vital functions in the waking state, when the individual is in a fasted condition, at normal body and room temperature, and without psychological stress Resting Metabolic Rate—The energy expended while an individual is resting quietly in a supine position

Standard Basal Metabolic Rate across the Age Span

Resting or Basal Metabolism (cont.) The impact of diet on resting metabolic rate Severe caloric restriction decreases RMR

Resting or Basal Metabolism (cont.) 2. The impact of exercise on resting metabolic rate - Transient increase - EPOC - A lot of speculation, but little clear evidence that an exercise bout changes RMR

Resting or Basal Metabolism (cont.) 3. The impact of exercise training on resting metabolic rate - Research is inconclusive. - RMR is related to muscle mass.

Thermogenesis Thermogenesis—The production of heat 1. The impact of diet on the thermic effect of a meal 2. The impact of exercise on the thermic effect of a meal 3. The impact of exercise training on the thermic effect of a meal

Exercise/Activity Energy Expenditure Diet does not affect energy expenditure with exercise Obviously, exercise increases exercise energy expenditure

Summary

II. The Effect of Diet, Exercise Training, and Diet Plus Exercise Training on BC and Weight Physiological Goals To lose body fat with special consideration to visceral abdominal fat To preserve fat-free weight To maintain or improve health To maintain or improve performance in athletes

Check Your Comprehension

Behavioral Compensation during Exercise Training and Individual Fat Loss

Body Composition and Anthropometric Changes in Response to Aerobic Exercise Training in Overweight/Obese Males and Females

Average Percent Body Fat of Male and Female Athletes (17–35 Years) in Selected Sports

The Effects of Diet Plus Exercise Training on Body Composition and Weight

The Effects of Diet, Exercise, and Diet Plus Exercise on Abdominal Obesity Significant relationship between aerobic exercise training and visceral fat reduction That although visceral fat reduction is significantly related to weight reduction during the aerobic exercise training, a significant reduction in visceral fat can occur without significant weight loss Dose-response relationship between the amount of aerobic exercise and the amount of visceral fat reduction

The Effect of Caloric Restriction with or without Exercise on Fat Loss

III. Application of TP for Weight and Body Composition Loss and/or Control A. Specificity - Diet plus exercise is recommended - Goal is caloric deficit of 3,500–7,000 kcal per week (500–1,000 per day) in order to loss 1-2 lb per week 1. Weight loss 2. Spot reductions 3. Prevent weight gain

III. Application of TP for Weight and Body Composition Loss and/or Control (cont.) B. Overload - Defined as net caloric deficit - Burning large number of calories is most beneficial, for many people this requires low- to moderate-intensity activity that is maintained for a long duration - 300 kcal per session, 3 days per wk

III. Application of TP for Weight and Body Composition Loss and/or Control (cont.) C. Rest/Recovery/Adaptation - The longer the caloric deficit is maintained, the more total weight that will be lost. - Early weight loss is due almost entirely to water loss.

III. Application of TP for Weight and Body Composition Loss and/or Control (cont.) D. Progression - As exercise can be tolerated better, more exercise may be completed, thus more calories expended. E. Individualization - Weight loss program should be devised based on individual measures of body composition and a diet analysis.

III. Application of TP for Weight and Body Composition Loss and/or Control (cont.) F. Retrogression/Plateau/Reversibility - Weight loss is fastest in initial stages - Not a linear pattern G. Maintenance - Key to maintenance is exercise training - Weight cycling—Repeated bouts of weight loss and regain Does not appear to negatively influence RMR or subsequent weight loss

Why Is It So Hard to Keep Weight Off? Lack of compliance Overestimation of weight/fat loss based on the 3,500 kcal rule A reduction in NEAT (nonexercise activity thermogenesis) A compensatory increase in energy intake Adaptive thermogenesis

IV. Making Weight for Sport