1. Chapter 8: Limiting Your Body
Fat Through Diet and Exercise
McGraw-Hill/Irwin © 2012 McGraw-Hill Companies. All Rights Reserved.

2. 8-2
Why should you be concerned
about body fat?
• Fat loss has become a multi-billion dollar
industry
– While there are numerous ideas and plans,
none can guarantee that the weight will stay
off
– Fat lost is often regained
• Most decide to lose weight due to
appearance, while others do it for health
reasons

3. 8-3
The American Lifestyle
• Food plays a major role in various aspects
of our lives
– Technology has resulted in Americans
becoming more sedentary
• Having excess body fat has reached
epidemic proportions in this country

4. 8-4
• Overweight:
– When an individual has excess body fat
relative to bone structure and height
• Obese:
– Individual has a large amount of excess body
fat
• Body Mass Index (BMI):
– Used to determine if a person is obese or
overweight
– Ratio of person’s body weight to height

5. 8-5

6. 8-6
How is fat stored and where do
you find it?
• Fat is found in all of the body’s cells
• Essential fat:
– Necessary for organ cushioning, temperature
regulation and storing energy
• Non-essential fat:
– Accumulates when food intake exceeds
energy demands
• Subcutaneous and visceral fat

7. 8-7
What determines how much fat
you have?
• Number of adipose cells
• Size of adipose cells
• Aging process
• Obesity in childhood

8. 8-8
What is body composition?
• Body composition:
– Refers to both fat and nonfat components of
the body
– The portion of total weight that is fat is the
percentage body fat
– Goal is to maximize lean body tissue

9. 8-9
How do you measure body
composition?
• Hydrostatic (underwater) weighing
• Bioelectrical impedance
• DXA (Dual Energy X-ray Absorptiometry)
• BOD POD Body Composition System
• Skinfold thickness

10. 8-10
How do you achieve caloric
balance?
• If you maintain weight, caloric balance has
been achieved
– Equal amount of calories in and out
• If the goal is weight gain, increased caloric
consumption is necessary = positive
balance
• Weight loss requires a negative caloric
balance

11. 8-11
How many calories do you
expend each day?
• Before planning a weight modification plan
you must:
– Know how much energy you consume daily
– Know how much energy you use daily
• Activity increases the need for energy
• Goal of any diet is to consume enough
energy to meet basic needs of tissue and
activity

12. 8-12
How many calories do you eat
each day?
• A sufficient number of calories is
necessary to maintain body weight and
composition
• Determining caloric intake requires
consulting food composition tables
• Factors unrelated to nutrition often
influence food consumption

13. 8-13
Assessing Your Caloric Balance
• If logs for estimating caloric intake and
expenditure are accurate, it should be
easy to determine caloric balance
• For weight loss, more calories must be
expended than consumed

14. 8-14
Set Point Theory of Weight Control
• Set Point Theory:
– Hypothesizes that the body maintains a
certain level of body fat
– Body has a set point or mechanism for
maintaining a specific body weight
– Operates like a thermostat
– Unclear how this set point is controlled
– Exercise and caloric restriction appear to be
critical in altering the set point

15. 8-15
What can you do to lose body
fat?
• Many fat reduction techniques are
available:
– Some are based on sound scientific and
nutritional principles
– Others are dangerous or waste money
• Losing body fat requires a negative caloric
balance
– Food/caloric consumption must be reduced
– Caloric expenditure must be increased

16. 8-16
Losing Weight by Dieting
• Fat loss through dieting alone is difficult
• Eating is often influenced by factors
outside of hunger
• Periodic dieting is ineffective
• Must avoid starvation dieting
– Starvation diets may actually reduce
metabolism
• Moderate reduction of total calories are
recommended to lose body fat

17. 8-17
Losing Body Fat by Exercising
• Weight loss through exercise results
primarily in loss of fat tissue, with little lean
body mass loss
• Establishing a new routine is critical and
requires motivation to acquire new fitness
habits
• Physical activity and caloric restriction at
any age can result in substantial weight
loss

18. 8-18
• Moderate Intensity Aerobic Activity
– Should workout at 60-70% of maximum aerobic
capacity
– Exercising above 70% while resulting in increased
calorie expenditure, fewer calories will be from fat
• Lean muscle stores will be utilized instead
• Spot Reducing
– Attempt at reducing body fat in a specific location
– During activity, fat is supplied from all areas of the
body not just in areas where muscle is active

19. 8-19
Losing Body Fat by Dieting and
Exercise
• Most efficient method of decreasing
percentage of body fat
• Everything in moderation
– Caloric expenditure and caloric restriction
combined
• Relatively fast and easy
– Easier to generate a negative caloric balance
• Weight loss should not exceed 1-2 pounds
per week

20. 8-20
Emphasizing the Long-haul
Approach to Minimizing Body
Fat
• It takes a long time to accumulate fat and it will
take time to lose it
• Many will take drastic measures to speed up the
process
– Unfortunately, normal eating habits usually return, as
does the weight
– Results in the yo-yo effect
– Makes subsequent weight loss more difficult because
body starts protecting fat stores

21. 8-21
Weight-Loss Gimmicks and
Fads
• Every year billions of dollars are spent trying to
lose weight quickly
• Claims are made about all sorts of products,
equipment, programs, gadgets, diet pills…
• People often become bored with the gimmick or
fad and lose interest
• There are numerous diets and eating plans
available
– Must be sure that it is safe and reliable

22. 8-22
Setting Realistic Goals
• Determine a desirable weight relative to
height, age and bone structure
– Must be reasonable and attainable
– If it is too high the person may become
discouraged
– Ultimate goal should be reaching a body fat
percentage that is realistic for your age group
• Set a safe rate of weight loss

23. 8-23
Health At Any Size
• Approach to health and well-being that
accepts:
– Natural diversity in body size
– Encourages people to stop focusing on weight
& dieting
• Helps people live well without encouraging
size/weight prejudices, phobias, poor body
image, or eating disorders

24. 8-24
• Principles:
– Accepting and respecting diversity of body size and
shape
– Recognizing health and well-being are multi-
dimensional
– Promoting all aspects of health and well-being for
people of all sizes
– Promoting eating in a manner which balances
individual nutritional needs, hunger, satiety, appetite
and pleasure
– Promoting individually appropriate, enjoyable, life-
enhancing, physical activity, rather than exercise that
is focused on goal of weight loss

25. 8-25
What if you want to increase
lean body mass?
• Can be achieved through muscle work
and increased food consumption
• Recommendation for weight gain
– 1-2 pounds per week
– Weight training must be involved or excess energy
will be converted into fat
– Be careful with protein supplements as we typically
consume ample amounts of protein

26. 8-26
What is disordered eating?
• Dieting and eating patterns resulting in
overweight and obesity are the most
common forms of disordered eating
• For some, weight loss is an obsession:
– Becomes a threat to health and well-being
– Often linked to body image and societal
pressures – to which the media contributes

27. 8-27
Bulimia Nervosa
• One of the more common eating disorders
• Periods of starvation, bingeing and
purging through vomiting, fasting and
laxatives/diuretics
• Most common in college-aged women
who are average in weight or not
excessively overfat

28. 8-28
Anorexia Nervosa
• Psychological disease
– Develops an aversion to food and distorted
body image
• Person will lose considerable amounts of
weight to the point where health is
threatened
• 90% of anorexics are female
• Appear overly thin to the point where they
lose their feminine shape

29. 8-29
Female Athlete Triad Syndrome
• Syndrome combining disordered eating,
amenorrhea and osteoporosis
• Definition may be too broad – as almost
any woman may fit this definition