1. Perspectives in Nutrition 5th ed. Gordon M.Wardlaw, PhD, RD, LD, CNSD
PowerPoint Presentation by
Dana Wu Wassmer, MS, RD

2. Chapter 13: Energy Balance and Weight Control

3. Energy Balance
“State in which energy intake, in the form of food and /or alcohol, matches the energy expended, primarily through basal metabolism and physical activity”
Positive energy balance
Energy intake > energy expended
Results in weight gain
Negative energy balance
Energy intake < energy expended
Results in weight loss

4. Energy Balance (Fig. 13-1)
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5. Estimating Kcal Content in Food
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Estimating Kcal Content in Food
Bomb calorimeter (Fig. 13-2)
Burns food inside a chamber surrounded by water
Heat is given off as food is burned
The increase in water temperature indicates the amount of energy in the food

6. Macronutrients and Fat Storage
Most fat is stored directly into adipose tissue
Body has unlimited ability to store fat (as fat)
Limited CHO can be stored as glycogen
Most CHO is used as a energy source
Excessive CHO will be synthesized into fat (for storage)

7. Macronutrients and Fat Storage
Protein is primarily used for tissue synthesis
Adults generally consume more protein than needed for tissue synthesis
Excess protein is used as a energy source
Some protein will be synthesized into fat (for storage)

8. Macronutrients and Fat Storage
Body prefers to use CHO as energy source
Only excess intake of CHO and protein will be turned into fat
Fat will remain as fat for storage
Physical activity encourages the burning of dietary fat

9. Energy In Vs. Energy Out NEAT Basal Metabolism
Dietary Intake Physical Activity
Thermic Effect of food

10. Basal Metabolism
The minimum energy expended to keep a resting, awake body alive
~60-70% of the total energy needs
Includes energy needed for maintaining a heartbeat, respiration, body temperature
Amount of energy needed varies between individuals

11. Influences On Basal Metabolism
Body surface area (weight, height)
Gender
Body temperature
Thyroid hormone
Age
Kcal intake
Pregnancy
Use of caffeine and tobacco

12. Physical Activity Increases energy expenditure beyond BMR
Varies widely among individuals
More activity, more energy burned
Lack of activity is the major cause of obesity

13. Thermic Effect of Food (TEF)
Energy used to digest, absorb, and metabolize food nutrients
“Sales tax” of total energy consumed
~5-10% above the total energy consumed
TEF is higher for CHO and protein than fat
Less energy is used to transfer dietary fat into adipose stores

14. Nonexercise Activity Thermogenesis
Nonvoluntary physical activity triggered by overeating
Fidgeting
Over eating increases sympathetic nervous system activity
Resists weight gain

15. Measurement of Body’s Energy Needs
Direct calorimetry
Measures heat output from the body using an insulated chamber
Expensive and complex
Indirect calorimetry
Measures the amount of oxygen a person uses
A relationship exists between the body’s use of energy and oxygen

16. Harris-Benedict Equation
Estimates resting energy needs
Considers height, weight, age, and gender
For men:
x(kg) + 5x(cm) - 6.8x(age in yr.)
For women:
x(kg) + 1.8x(cm) - 4.7x(age in yr.)

17. Sample Calculations Man: 21 yr., 5’10” (171 cm), 155# (70 kg)
x(70kg) + 5x(171cm) x(21) = 1745 kcal/day
Woman: 21 yr., 5’10” (171 cm), 155# (70kg)
x(70kg) + 1.8x(171cm) - 4.7x(21)= 1536 kcal/day

18. Why Do You Eat? Hunger Appetite Physiological (internal) drive to eat
Controlled by internal body
Appetite
Psychological (external) drive to eat
Often in the absence of hunger
e.g., seeing/smelling fresh baked chocolate chip cookies

19. Satiety Regulator The hypothalamus Sympathetic nervous system
When feeding cells are stimulated, they signal you to eat
When satiety cells are stimulated, they signal you to stop eating
Sympathetic nervous system
When activity increases, it signals you to stop eating
When activity decreases, it signals you to eat

20. Influences of Satiety (Fig. 13-4a)
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21. Influences of Satiety (Fig. 13-4b)
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22. Influenced By Body Composition
Leptin
A hormone produced by the adipose tissue
Increases with larger fat mass (and decrease desire to eat)
Decreases with lower fat mass (and enhance desire to eat)
Acts to decrease activity of neuropeptide Y
Neuropeoptide Y
Increases food intake
Reduces energy expenditure

23. Hormonal Influence Endorphins CCK Serotonin
Natural body tranquilizer that can prompt you to eat
CCK
Along with gastrointestinal distention, decreases hunger (and desire to eat)
Serotonin
Neurotransmitter that is released as a result of CHO intake
High levels appear to decrease desire to eat CHO and induce calmness

24. Hormonal Influence Nutrient receptors In small intestine
Elicit feeling of satiety
Communicate with the brain via nerves
Inform brain of the presence of nutrients in the small intestine
Feeling of satiety with the infusing of CHO or fats in the small intestine

25. Nutrients Influence
Presence of energy yielding nutrient registers satiety in the brain
Apolipoprotein A-IV on the chylomicrons signals satiety in the brain
Absence of these nutrients will signal hunger

26. Why We Eat Appetite is affected by a variety of external forces
Combination of internal and external signals drive us to eat
Not a perfect system; desire to eat can be overwhelming

27. What is a Healthy Body Weight?
Based on how you feel, weight history, fat distribution, family history of obesity-related disease, current health status, and lifestyle
Current height/weight standards only provide guides

28. Body Mass Index (BMI) The preferred weight-for-height standard
Calculation:
Body wt (in kg) OR Body wt (in lbs) x 703.1
[Ht (in m)] [Ht (in inches)]2
Health risks increase when BMI is > 25

29. Estimation of Healthy Weight
For men:
106 pounds for the first 5 feet
add 6 pounds per each inch over five feet
A man who is 5’10” should weigh 166 lbs.
For women:
100 pounds for the first 5 feet
add 5 pounds per each inch over five feet
A women who is 5’10” should weigh 150 lbs.

30. Obesity Excessive amount of body fat
Women with > 30-35% body fat
Men with > 25% body fat
Increased risk for health problems
Are usually overweight
Measurements using calipers

31. Estimation of Body Fat Underwater weighing (Fig. 13-5) Most accurate
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Estimation of Body Fat
Underwater weighing (Fig. 13-5)
Most accurate
Fat is less dense than lean tissue
Fat floats

32. Estimation of Body Fat Bioelectrical impedance
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Estimation of Body Fat
Bioelectrical impedance
Low-energy current to the body that measures the resistance of electrical flow
Fat is resistant to electrical flow; the more the resistance, the more body fat you have
X-ray photon absorptiometry
An X-ray body scan that allows for the determination of body fat
Infrared light
Assess the interaction of fat and protein in the arm muscle

33. Body Fat Distribution Upper-body (android) obesity--”Apple shape”
Associated with more heart disease, HTN, Type II Diabetes
Abdominal fat is released right into the liver
Fat affects liver’s ability to clear insulin and lipoprotein
Encouraged by testosterone and excessive alcohol intake
Defined as waist to hip ratio of >1.0 in men and >0.8 in women

34. Body Fat Distribution (Fig.13-9)
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35. Body Fat Distribution Lower-body (gynecoid) obesity--”Pear shape”
Encouraged by estrogen and progesterone
After menopause, upper-body obesity appears
Less health risk than upper-body obesity

36. Overweight and Obesity
Underweight = BMI < 18.5
Healthy weight = BMI
Overweight = BMI
Obese = BMI
Severely obese = BMI >40

37. Juvenile-Onset Obesity
Develops in infancy or childhood
Increase in the number of adipose cells
Adipose cells have long life span and need to store fat
Makes it difficult to loose the fat (weight loss)

38. Adult-Onset Obesity Develops in adulthood
Fewer (number of) adipose cells
These adipose cells are larger (stores excess amount of fat)
If weight gain continues, the number of adipose cells can increase

39. Causes of Obesity Nature debate
Identical twins raised apart have similar weights
Genetics account for ~40% of weight differences
Genes affect metabolic rate, fuel use, brain chemistry
Thrifty metabolism gene allows for more fat storage to protect against famine

40. Causes of Obesity Nurture debate
Environmental factors influence weight
Learned eating habits
Activity factor (or lack of)
Poverty and obesity
Female obesity is rooted in childhood obesity
Male obesity appears after age 30

41. Nature and Nurture
Obesity is nurture allowing nature to express itself
Location of fat is influenced by genetics
A child with no obese parents has a 10% chance of becoming obese
A child with 1 obese parent has a 40% chance
A child with 2 obese parents has a 80% chance

42. Nature Vs. Nurture
Those at risk for obesity will face a lifelong struggle with weight
Gene does not control destiny
Increased physical activity, moderate intake can promote healthy weight

43. Set Point Theory Weight is closely regulated by the body
Genetically predetermined body weight
Body resists weight change
Leptin assists in weight regulation
Weight returns after weight loss
Reduction in energy intake results in lower metabolic rate
Ability to shift the set point weight

44. Why Diets Don’t Work Obesity is a chronic disease
Treatment requires long-term lifestyle changes
Dieters are misdirected
More concerned about weight loss than healthy lifestyle
Unrealistic weight expectations

45. Why Diets Don’t Work Body defends itself against weight loss
Thyroid hormone concentrations (BMR) drop during weight loss and make it more difficult to lose weight
Activity of lipoprotein lipase increases making it more efficient at taking up fat for storage

46. Why Diets Don’t Work Weight cycling (yo-yo dieting)
Typically weight loss is not maintained
Weight lost consists of fat and lean tissue
Weight gained after weight loss is primarily adipose tissue
Weight gained is usually more than weight lost
Associated with upper body fat deposition

47. Why Diets Don’t Work Weight gain in adulthood
Weight gain is common from ages 25-44
BMR decreases with age
Inactive lifestyle
Changes in body composition
Fluid is usually the first weight lost
Loss in lean body tissue means lowering the BMR
Very little fat is lost during weight loss

48. Lifestyle Vs. Weight Loss
Prevention of obesity is easier than curing
Balance energy in(take) with energy out(put)
Focus on improving food habits
Focus on increase physical activities

49. What It Takes To Lose a Pound
Body fat contains 3500 kcal per pound
Fat storage (body fat plus supporting lean tissues) contains 2700 kcal per pound
Must have an energy deficit of kcal to lose a pound per week

50. Do the Math
To lose one pound, you must create a deficit of kcal
So to lose a pound in 1 week (7 days), try cutting back on your kcal intake and increase physical activity so that you create a deficit of kcal per day
- 500 kcal x 7 days = kcal = 1 pound of weight loss
day week in 1 week

51. Sound Weight Loss Program
Meets nutritional needs, except for kcal
Slow & steady weight loss
Adapted to individuals’ habits and tastes
Contains enough kcal to minimize hunger and fatigue
Contains common foods
Fit into any social situation
Chang eating problems/habits
Improves overall health
See a physician before starting

52. Cutting Back
Control calorie intake by being aware of kcal and fat content of foods
“Fat Free” does not mean “Calories Free” (or “All You Can Eat”)
Read food labels
Estimate kcal using the exchange system
Keep a food diary

53. Regular Physical Activity
Fat use is enhanced with regular physical activity
Increases energy expenditure
Duration and regularity are important
Make it a part of a daily routine

54. Behavior Modification
Modify problem (eating) behaviors
Chain-breaking
Stimulus control
Cognitive restructuring
Contingency management
Self-monitoring

55. Chain-Breaking Breaking the link between two behaviors
These links can lead to excessive intake
Snacking while watching T.V.

56. Stimulus Control
Alternating the environment to minimize the stimuli for eating
Puts you in charge of temptations

57. Cognitive Restructuring
Changing your frame of mind regarding eating
Replace eating due to stress with “walking”

58. Contingency Management
Forming a plan of action in response to a situation
Rehearse in advance appropriate responses to pressure of eating at parties

59. Self-Monitoring Tracking foods eaten and conditions affecting eating
Helps you understand your eating habits

60. Weight Maintenance Prevent relapse Have social support
Occasional lapse is fine, but take charge immediately
Continue to practice newly learned behavior
Requires “motivation, movement, and monitoring”
Have social support
Encouragement from friends/ family/ professionals

61. Dieting Can Be Hazardous To Your Health
Weight regained consists of a higher percentage of body fat than before
Less healthy than before dieting
Weight loss diet should not be considered unless you are committed and motivated

62. Diet Drugs Amphetamine (Phenteramine) Sibutramine (Meridia)
Prolongs the activity of epinephrine and norepinephrine in the brain
Decreases appetite
Not recommended for long term use
Sibutramine (Meridia)
Enhances norepinephrine and serotonin activity
Decreases appetite(eat less)
Not recommended for people with HTN

63. Diet Drugs Orlistat (Xenical) Inhibits fat digestion
Reduces absorption of fat in the small intestine
Fat is deposited in the feces with its side effects
Must control fat intake
Malabsorption of fat-soluble vitamins
Supplements needed

64. Homeopathic drug Ephedrine (ma huang) St. John’s Wort
Linked to illnesses and death
Associated with nervous and cardiovascular disorder
St. John’s Wort
Antidepressant
Both taking together
Not recommended until careful testing is done

65. Over-The-Counter Diet Aids
Phenylpropanolamine
Epinephrine-like drug
Cause a slight decrease in food intake
Fiber
“Filler” leading to satiety
Causes stomach distention
Benzocaine
Numbs the tongue and taste buds

66. Very Low-Calorie Diets (VLCD)
Recommended for people >30% above their healthy weight
kcal per day
Low carbohydrates and high protein
Causes ketosis
Lose ~3-4 pounds a week
Requires careful physician monitoring
Health risks includes cardiac problems and gallstones

67. Gastroplasty - Stomach Stapling
Common surgical procedure for treating severe obesity
Reduces the stomach size (from 4 cups) to half a shot glass size (1 oz)
Overeating will result in rapid vomiting
Smaller stomach promotes satiety earlier
75% will lose ~50% of excess body weight
Costly
Dumping syndrome

68. Gastroplasty (Fig )
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69. Underweight is Also a Problem
15-25% below healthy weight or BMI of <18.5
Associated with increased deaths, menstrual dysfunction, pregnancy complications, slow recovery from illness/surgery
Causes are the same as for obesity but in the opposite route

70. Treatment for Underweight
Intake of energy-dense foods (energy input)
Encourage meals and snacks
Reduce activity (energy output)
To gain a pound you need a total excess intake of kcal