1. Energy Balance and Body Composition
Chapter 8

2. Energy Balance Excess energy stored as fat
Fat used for energy between meals
Energy balance: energy in = energy out
Imbalance causes weight changes
Not simply fat changes
Classic rule
1 pound of fat = 3500 kcalories
Not exactly correct
Differs with gender and weight

3. Measuring Food Energy Direct measure of food’s energy value
Bomb calorimeter
Indirect measure of energy released
Oxygen consumed
kCalorie calculations
Figure 8-1 Bomb calorimeter

4. Food Intake Hunger Satiation – signal to stop eating
Physiological response to nerve signals and chemical messengers
Hypothalamus
Influences
Satiation – signal to stop eating
Satiety – signal to not to start eating again

5. Hunger, Satiation, and Satiety
Figure 8-2 Hunger, satiation, and satiety

6. Factors That Influence Eating
Overriding hunger and satiety
Stress eating
External cues
Time of day, availability, sight, taste of food
Environmental influences
Examples
Cognitive influences
Disordered eating

7. Nutrient Composition for Sustained Satiation and Satiety
Protein is most satiating
Low-energy density
High-fiber foods
High-fat foods – strong satiety signals
Figure 8-3 How fat influences portion sizes

8. The Hypothalamus Control center for eating Integrates messages
Energy intake, expenditure, and storage
Gastrointestinal hormones
Influence appetite control and energy balance

9. Energy Out Thermogenesis Total energy components Heat generation
Measure of energy expended
Total energy components
Basal metabolism
Physical activity
Food consumption
Adaptation

10. Basal Metabolism Represents about two-thirds of daily energy
Metabolic activities
All basic processes of life
Basal metabolic rate (BMR)
Variations
Weight
Lean tissue
Resting metabolic rate (RMR)

11. Factors that Affect the BMR
Effect on BMR
Age
Lean body mass diminishes with age, slowing the BMR.a
Height
In tall, thin people, the BMR is higher.b
Growth
In children, adolescents, and pregnant women, the BMR is higher.
Body composition (gender)
The more lean tissue, the higher the BMR (which is why males usually have a higher BMR than females). The more fat tissue, the lower the BMR.
Fever
Fever raises the BMR.C
Stresses
Stresses (including many diseases and certain drugs) raise the BMR.
Environmental temperature
Both heat and cold raise the BMR.
Fasting/starvation
Fasting/starvation lowers the BMR.d
Malnutrition
Malnutrition lowers the BMR.
Hormones (gender)
The thyroid hormone thyroxin, for example, can speed up or slow down the BMR.e Premenstrual hormones slightly raise the BMR.
Smoking
Nicotine increases energy expenditure.
Caffeine
Caffeine increases energy expenditure.
Sleep
BMR is lowest when sleeping.
Table 8-2 Factors that affect the BMR
a The BMR begins to decrease in early adulthood (after growth and development cease) at a rate of about 2 percent/decade. A reduction in voluntary activity as well brings the total decline in energy expenditure to about 5 percent/decade. b If two people weigh the same, the taller, thinner person will have the faster metabolic rate, reflecting the greater skin surface, through which heat is lost by radiation, in proportion to the body's volume (see Figure 8-5, p. 239). c Fever raises the BMR by 7 percent for each degree Fahrenheit. d Prolonged starvation reduces the total amount of metabolically active lean tissue in the body, although the decline occurs sooner and to a greater extent than body losses alone can explain. More likely, the neural and hormonal changes that accompany fasting are responsible for changes in the BMR. e The thyroid gland releases hormones that travel to the cells and influence cellular metabolism. Thyroid hormone activity can speed up or slow down the rate of metabolism by as much as 50 percent.

12. Physical Activity Voluntary movement of skeletal muscles
Most variable component of energy expenditure
Amount of energy needed
Muscle mass
Body weight
Activity
Frequency, intensity, and duration

13. Thermic Effect of Food
Acceleration of GI tract functioning in response to food presence
Releases heat
Approximately 10 percent of energy intake
High-protein foods versus high-fat foods
Meal consumption time frame

14. Adaptive Thermogenesis
Adapt to dramatically changing circumstances
Examples
Extra work done by body
Amount expended is extremely variable
Not included in energy requirement calculations

15. Components of Energy Expenditure
Figure 8-4 Components of energy expenditure

16. Estimating Energy Requirements
Gender
BMR
Growth
Groups with adjusted energy requirements
Age
Changes with age
Physical activity
Levels of intensity for each gender
Body composition and body size
Height
Weight

17. Ideal Body Weight: Criteria
The criterion of fashion
Perceived body image and actual body size
Damaging behaviors
Social standards for “ideal”
Subjective
Little in common with health
The criterion of health
Enough fat to meet basic needs
Not so much to incur health risks

18. Tips for Accepting a Healthy Body Weight
• Value yourself and others for human attributes other than body weight. Realize that prejudging people by weight is as harmful as prejudging them by race, religion, or gender.
• Use positive, nonjudgmental descriptions of your body.
• Accept positive comments from others.
• Focus on your whole self including your intelligence, social grace, and professional and scholastic achievements.
• Accept that no magic diet exists.
• Stop dieting to lose weight. Adopt a lifestyle of healthy eating and physical activity permanently.
• Follow the USDA Food Patterns. Never restrict food intake below the minimum levels that meet nutrient needs.
• Become physically active, not because it will help you get thin but because it will make you feel good and improve your health.
• Seek support from loved ones. Tell them of your plan for a healthy life in the body you have been given.
• Seek professional counseling, not from a weight-loss counselor, but from someone who can help you make gains in self-esteem without weight as the primary focus.
• Appreciate body weight for its influence on health, not appearance
Table 8-5 Tips for accepting a healthy body weight

19. Body Mass Index (BMI) Measure of relative weight for height
BMI= weight (kg) height m 2
Health-related classifications
Healthy weight: BMI = 18.5 to 24.9
Other classifications
Not a measure of body composition
Muscular athletes
Impact of ethnicity

20. BMI Table Table 8-6 BMI table Under-weight (<18.5) Healthy Weight
Under-weight
(<18.5)
Healthy Weight
( )
Overweight
( )
Obese
(≥ 30) 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40
Height
Body weight (pounds)
4"10" 86 91 96
100
105
110
115
119
124
129
134
138
143
148
153
158
162
167
172
177
181
186
191
4'11" 89 94 99
104
109
114
128
133
163
168
173
178
183
188
193
198
5'0" 92 97
102
107
112
118
123
174
179
184
189
194
199
204
5'1" 95
106
111
116
122
127
132
137
164
169
180
185
190
195
201
206
211
5'2" 98
120
126
131
136
142
147
175
196
202
207
213
218
5'3"
113
130
135
141
146
152
197
203
208
214
220
225
5'4"
140
145
151
157
192
209
215
221
227
232
5'5"
108
144
150
156
210
216
222
228
234
240
5'6"
155
161
223
229
235
241
247
5'7"
121
159
166
217
230
236
242
249
255
5'8"
125
171
243
256
262
5'9"
149
176
182
250
257
263
270
5'10"
139
160
264
271
278
5'11"
165
200
265
272
279
286
6'0"
154
258
287
294
6'1"
212
219
280
288
295
302
6'2"
233
303
311
6'3"
224
248
319
6'4"
205
238
246
254
304
312
320
328
6'5"
244
252
261
269
277
336
6'6"
259
267
276
284
293
310
345
Table 8-6 BMI table

21. BMI and Body Shapes
Figure 8-6 BMI and body shapes

22. Distribution of Body Weights in US Adults
Figure 8-7 Distribution of body weights in US adults

23. Body Fat and Its Distribution
Important information for disease risk
How much of weight is fat?
Where is fat located?
Ideal amount of body fat depends on person
Age (yr)
Ideal (Healthy weight, average fitness)
Actual
(US average)
Male
20-39
18-21%
26%
40-59
22-25%
29%
60+
24-27%
31%
Female
23-26%
38%
28-32%
41%
31-34%
42%
Table 8-8 Percent body fat
SOURCE: L. G. Borrud and coauthors. Body composition data for individuals 8 years of age and older: US population, , Vital and Health Statistics 11 (2010): 1-87; ACSM's Health-Related Physical Fitness Assessment Manual, 2nd ed. (Baltimore, M.D.: Lippincott Williams & Wilkins, 2008), p. 59.

24. Central Obesity Needing less body fat Needing more body fat
Some athletes
Needing more body fat
Example groups
Fat distribution
Visceral fat
Central obesity
Subcutaneous fat
Figure 8-8 A central obesity

25. “Apple” and “Pear” Body Shapes Compared
Figure 8-9 “Apple” and “pear” body shapes compared

26. Waist Circumference Indicator of fat distribution and central obesity
Women: greater than 35 inches
Men: greater than 40 inches
Waist-to-hip ratio
Other body composition measurement techniques
More precise measures

27. Common Methods Used to Assess Body Fat
Figure 8-10 Common methods used to assess body fat

28. Health Risks Associated with Body Weight and Body Fat
Body weight and fat distribution correlate with disease risk and life expectancy
Correlations are not causes
Risks associated with being underweight
Fighting against wasting diseases
Menstrual irregularities and infertility
Osteoporosis and bone fractures

29. BMI and Mortality
Figure 8-11 BMI and mortality

30. Risks Associated With Being Overweight
Obesity is a designated disease
Health risks
More likely to be disabled in later years
Costs
Medical costs
Lost productivity
Lives

31. Specific Disease Risks
Cardiovascular disease
Elevated blood cholesterol and hypertension
Central obesity
Diabetes – type II
Weight gains and body weight
Cancer
Risk of some cancers increases with body weight
Relationships not fully understood

32. Inflammation and the Metabolic Syndrome
Change in body’s metabolism
Cluster of symptoms
Fat accumulation
Inflammation
Elevated blood lipids
Promote inflammation
Fit and fat versus sedentary and slim
Fitness offers many health benefits

33. Eating Disorders
Highlight 8

34. Eating Disorders, continued
Three disorders
Anorexia nervosa
Bulimia nervosa
Binge eating disorder
Prevalence of various eating disorders
Causes
Multiple factors
Athletes and eating disorders

35. Female Athlete Triad Disordered eating Amenorrhea Osteoporosis
Unsuitable weight standards
Body composition differences
Risk factors for eating disorders in athletes
Amenorrhea
Characteristics
Osteoporosis
Stress fractures

36. The Female Athlete Triad Illustrated
Figure H8-1 The female athlete triad

37. Other Dangerous Practices of Athletes
Muscle dysmorphia
Characteristic behaviors
Similarities to others with distorted body images
Food deprivation and dehydration practices
Impair physical performance
Reduce muscle strength
Decrease anaerobic power
Reduce endurance capacity

38. Tips for Combating Eating Disorders
General Guidelines
• Never restrict food amounts to below those suggested for ade­quacy by the USDA Food Patterns (see Table 2-2 on p. 44).
• Eat frequently. Include healthy snacks between meals. The person who eats frequently never gets so hungry as to allow hunger to dictate food choices.
• If not at a healthy weight, establish a reasonable weight goal based on a healthy body composition.
• Allow a reasonable time to achieve the goal. A reasonable loss of excess fat can be achieved at the rate of about 10 percent of body weight in 6 months.
• Establish a weight-maintenance support group with people who share interests.
Specific Guidelines for Athletes and Dancers
• Replace weight-based goals with performance-based goals.
• Restrict weight-loss activities to the off-season.
• Remember that eating disorders impair physical performance. Seek professional help in obtaining treatment if needed.
• Focus on proper nutrition as an important facet of your training, as important as proper technique.
Table H8-1 Tips for combating eating disorders

39. Anorexia Nervosa Distorted body image Malnutrition Denial
Central to diagnosis
Cannot be self-diagnosed
Malnutrition
Impacts brain function and judgment
Causes lethargy, confusion, and delirium
Denial
Levels are high among anorexics

40. Characteristics of Anorexia Nervosa
Need for self-control
Impact on body
Growth ceases and normal development falters
Changes in heart size and strength
Mineral imbalance
Death can occur from multiple organ system failure

41. Treatment of Anorexia Nervosa
Multidisciplinary approach
Food and weight issues
Relationship issues
Treatment involves family members
Different approaches for low, medium, and high risk patients
High mortality rate among psychiatric disorders

42. Bulimia Nervosa Distinct and more prevalent than anorexia nervosa
True incidence difficult to establish
Secretive nature
Not as physically apparent
Common background characteristics of bulimics

43. Characteristics of Bulimia Nervosa
Binge-purge cycle
Lack of control
Consume food for emotional comfort
Cannot stop
Done in secret
Purge
Cathartic
Emetic
Shame and guilt

44. The Vicious Cycle of Restrictive Dieting and Binge Eating
Figure H8-2 The vicious cycle of restrictive dieting and binge eating

45. Negative self-perceptions Restrictive dieting Purging Binge eating
Figure H8-2 The Vicious Cycle of Restrictive Dieting and Binge Eating
Binge eating
Stepped Art

46. Effects of Bulimia Nervosa
Physical consequences of binge-purge cycle
Subclinical malnutrition
Effects
Physical effects
Tooth erosion, red eyes, and calloused hands
High rates of clinical depression and substance abuse

47. Treatment of Bulimia Nervosa
Discontinuing purging and restrictive diet habits
Learn to eat three meals a day
Plus snacks
Treatment team
Length of recovery
Overlap between anorexia nervosa and bulimia nervosa

48. Diet Strategies for Combating Bulimia Nervosa
Planning Principles • Plan meals and snacks; record plans in a food diary prior to eating. • Plan meals and snacks that require eating at the table and using utensils. • Refrain from finger foods. • Refrain from "dieting" or skipping meals. Nutrition Principles • Eat a well-balanced diet and regularly timed meals consisting of a variety of foods. • Include raw vegetables, salad, or raw fruit at meals to prolong eating times. • Choose whole-grain, high-fiber breads, pasta, rice, and cereals to increase bulk. • Consume adequate fluid, particularly water. Other Tips • Choose foods that provide protein and fat for satiety and bulky, fiber-rich carbohydrates for immediate feelings of fullness. • Try including soups and other water-rich foods for satiety. • Choose portions that meet the definition of "a serving" according to the USDA Food Patterns (pp ). • For convenience (and to reduce temptation) select foods that naturally divide into portions. Select one potato, rather than rice or pasta that can be overloaded onto the plate; purchase yogurt and cottage cheese in individual containers; look for small packages of precut steak or chicken; choose frozen dinners with measured portions. • Include 30 minutes of physical activity every day—exercise may be an important tool in defeating bulimia.
Table H8-2 Diet strategies for combating bulimia nervosa

49. Binge-Eating Disorder
Periodic binging
Typically no purging
Contrast with bulimia nervosa
Similarities to bulimia nervosa
Feelings
Differences between obese binge eaters and obese people who do not binge
Behavioral disorder responsive to treatment

50. Eating Disorders in Society
Society plays central role in eating disorders
Known only in developed nations
More prevalent as wealth increases
Food becomes plentiful
Body dissatisfaction
Incidence in young people
Increased steadily since the 1950s