1. Energy Balance and Body Composition
Studying = 1 or 2 kcalories/minute

2. Energy Balance

3. Energy Balance
Energy In:
How is it measured?
What controls it?

4. Food Composition Bomb calorimeter
Calorie = the amount of energy necessary to raise a ml of water 1 degree.
Food calories = kCalories

5. Food Composition Direct calorimetry vs. indirect calorimetry
Actually burning food to measure calories versus measuring respiration
Physiological fuel value
How well the body can utilize the calories

6. Physiological Fuel Value

7. Food Intake Hunger: the feeling that motivates us to eat
Appetite: sights, smells, thoughts that motivate us to eat.
Satiation: feeling of fullness
Satiety: the feeling that reminds us not to eat again.

8. Food Intake Regulation of intake Prompts eating; physiological desire
Hunger
Prompts eating; physiological desire
Satiation
Signals to stop eating
Satiety
Lack of hunger
Appetite
Psychological desire

9. Food Intake

10. Appetite Factors affecting appetite Hormones Inborn appetites
Learned preferences, aversions, timings
Customary eating habits
Social interactions
Some disease states
Appetite stimulants, depressants, mood-altering drugs
Environmental conditions

11. Food Intake Sustaining satiation and satiety
lower-fat foods can be eaten in larger portions for the same number of kcalories

12. Energy Balance
Energy Out:
Where does it go?

13. Thermogenesis
Thermogenesis is the term for expenditure of calories (or heat generation). There are four main types:
Basal metabolic
Exercise-induced
Diet-induced
Adaptive

14. Components of Energy Expenditure
Basal metabolic rate (BMR)
Energy to maintain body temperature, breathing, making new cells, heart beating, and kidney function.
2/3 of energy

16. How to estimate calories needed to meet BMR
Men: body weight (lbs) times 11
Women: body weight (lbs) times 10
170 lb man X 11 = 1870 cals/day
135 lb woman X 10 = 1350 cals/day

17. Components of Energy Expenditure
Exercise Induced

18. How to estimate calories needed to meet activity.
Amount spent depends on activity level
Inactive 30% of basal metabolism calories
Average 50% of basal metabolism calories
Active 75% of basal metabolism calories
Example: if basal metabolism = 1500
Inactive person 1500 X .30 = 450 calories
Average person 1500 X .50 = 750 calories
Active person 1500 X .75 = 1125 calories

21. Components of Energy Expenditure
Thermic effect of food (TEF)
Energy of digestion
10% of calories are to digest the food
"McStomachache, McGurgles, McGas"!

22. Components of Energy Expenditure
Adaptive Thermogenesis
Extreme reactions to the environment; cold, heat, overeating, starvation, trauma.

23. How many calories do you need?
Total daily need for calories =
Basal metabolic rate 1500
Activity (inactive) 450
Dietary thermogenesis 195
TOTAL = calories

24. Estimating Energy Requirements
Gender
Growth
Age
Body composition
Body size

25. Estimating Energy Requirements
Gender: women have lower BMR than men
Growth: BMR is higher in growth and pregnancy
Age: BMR declines with age

26. Estimating Energy Requirements
Physical activity

27. Estimating Energy Requirements
Body composition

28. Estimating Energy Requirements
Body size

29. Energy Balance Measuring energy balance: BMI Waist to Hip ratio.
Body fat percentage

30. Defining Healthy Body Weight
The criterion of health
Body mass index (BMI)
=weight (kg)/height (m)2

31. BMI Values Used to Assess Weight

32. BMI and Mortality

33. Distribution of Body Weights in U.S. Adults

34. Defining Healthy Body Weight
The criterion of fashion: BMI of Miss America

35. Age-Adjusted Prevalence of Overweight BMI (25–29
Age-Adjusted Prevalence of Overweight BMI (25–29.9) and Obesity (BMI >30)
Percent
This slide depicts data from several NHANES surveys using the panel’s definition of overweight as a BMI of 25 to 29.9 kg/m2 and of obesity as a BMI of greater than or equal to 30 kg/m2.
From 1960 to 1994, the prevalence of overweight increased slightly from 37.8 to 39.4 percent in men and from 23.6 to 24.7 percent in women. In men and women together, overweight increased from 30.5 to 32.0 percent.
During the same time period, however, the prevalence of obesity increased from 10.4 to 19.9 percent in men and from 15.1 to 24.9 percent in women. In men and women together, obesity increased from 12.8 to 22.5 percent. Most of the increase in obesity occurred in the past decade.
BMI 25–29.9
BMI >30
CDC/NCHS, United States, , ages years
CORE SET II

36. NHANES III Prevalence of Hypertension* According to BMI
Percent
Data from NHANES III show that the prevalence of high blood pressure increases progressively with higher levels of BMI in men and women.
The prevalence of high blood pressure in adults with BMI >30 is 41.9 percent for men and percent for women, respectively, compared with 14.9 percent for men and 15.2 percent for women with BMI 25.
Other studies, such as the large international Intersalt study, carried out in more than 10,000 men and women, also reported a 10 kg (22 lb) higher body weight to be associated with a 3 mm Hg systolic and 2.3 mm Hg diastolic change in blood pressure.
These differences in blood pressure, as shown in the Intersalt study, translate into a 12 percent increased risk for CHD and 24 percent increased risk for stroke.
*Defined as mean systolic blood pressure 140 mm Hg, mean diastolic 90 mm Hg, or currently taking antihypertensive medication.
Brown C et al. Body Mass Index and the Prevalence of Hypertension and Dyslipidemia. Obes Res. 2000; 8:
CORE SET II

37. NHANES III Prevalence of High Blood Cholesterol* According to BMI
Percent
The NHANES III data on high blood cholesterol also show that the prevalence of high blood cholesterol increases at higher BMI levels. High blood cholesterol is defined as a cholesterol level of  240 mg/dL.
Among men, the prevalence of high blood cholesterol ranged from 13% at the lowest BMI level to 22% at the highest BMI level.
At each BMI level, the prevalence of high blood cholesterol is greater in women than in men.
In women, there is a significant increase in the prevalence of high blood cholesterol from BMI level <25 to BMI level 25–26.
*Defined as >240 mg/dL.
Brown C et al. Body Mass Index and the Prevalence of Hypertension and Dyslipidemia. Obes Res. 2000; 8:
CORE SET II

38. NHANES III Prevalence of Low HDL-Cholesterol* According to BMI
Percent
This slide shows that with increasing BMI levels, the prevalence of low HDL increases in both men and women. Low HDL was defined here as <35 mg/dL in men and <45 mg/dL in women.
The prevalence of low HDL is more prevalent in women than in men at each level of BMI.
Although low HDL-cholesterol in this study was defined as <35 mg/dL in men and <45 mg/dL in women, the Third Report of the National Cholesterol Education Program’s Expert Panel on the Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults defines low HDL-cholesterol as <40 mg/dL for men and women.
*Defined as <35 mg/dL in men and <45 mg/dL in women.
Brown C et al. Body Mass Index and the Prevalence of Hypertension and Dyslipidemia. Obes Res. 2000;8:
CORE SET II

39. Hypertension Percentage60 50 40
Percentage 30 20
Data in the next 8 slides show results of a population-based longitudinal study by Brown and colleagues. The Australian Longitudinal Study on Women’s Health enrolled 13,431 women who participated in a baseline survey of selected indicators of health and well-being for middle-aged women, age The study explored the associations between body mass index and selected indicators of health and well-being; surgical procedures(cholescystectomy, hysterectomy), symptoms like back pain, and number of visits to general practitioners or specialists. BMI was calculated using self-reported height and weight, corrected following the method of Waters. Hypertension shows a strong monotonic relationship with BMI.
Trend curve estimates the relationship between BMI and hypertension. The percentage of reported hypertension increases with increasing body mass index.
The prevalence of hypertension at different levels of BMI were 10.6%(BMI <20), 13.3% (BMI>20<25), 22.8%(BMI>30<40), and 61.3%(BMI>40).
There was a 6-fold increase in the odds ratio of hypertension between women with BMI<20 and women with BMI >40. 10 20 25 30 35 40
BMI
Relationship between BMI and crude percentage of women reporting
medical problems, surgical procedures, symptoms, and health care utilization.
Brown WJ et al. Int J Obes 1998;22:
BACKGROUND V

40. Diabetes Percentage BMI15 10
Percentage 5
Diabetes, as described in the study by Brown and colleagues of Australian women , shows a monotonic relationship with BMI.
The prevalence of diabetes increases 6-fold between women with a BMI < 20 and women with a BMI > 40.
Most of the increase in diabetes prevalence occurs in women with BMI >30. Prevalence is 1.6% at BMI < 20, 1.4% at BMI > 20-< 25, 3.2% at BMI > 25-< 30, 5.9% at BMI > 30-< 40, and 19.3% at BMI > 40.
There is a 16-fold increase in the odds ratio for diabetes between women with BMI < 20 and women with BMI > 40. 20 25 30 35 40
BMI
Relationship between BMI and crude percentage of women reporting
medical problems, surgical procedures, symptoms, and health care utilization.
Brown WJ et al. Int J Obes 1998;22:
BACKGROUND V

41. Cholescystectomy Percentage BMI25 20
Percentage 15 10
In the study by Brown and colleagues, the relationship between BMI and cholescystectomy also shows an upward trend with increasing BMI.
A linear increase of increasing surgical procedures is seen for cholescystectomy as BMI increases.
There is a 7-fold increase in the odds ratio of cholescystectomy in women with a BMI of < 20 compared to women with a BMI of > 40. 5 20 25 30 35 40
BMI
Relationship between BMI and crude percentage of women reporting
medical problems, surgical procedures, symptoms, and health care utilization.
Brown WJ et al. Int J Obes 1998;22:
BACKGROUND V

42. Hysterectomy Percentage BMI40 35 30
Percentage 25 20
This trend curve shows the relationship between BMI and hysterectomy in Australian women in the study by Brown and colleagues. However, the greatest prevalence of hysterectomy occurs in women with BMI > 30 and < 40.
The general trend continues to show women with the lowest BMI having this surgical procedure less often than those with a higher BMI.
There is a higher risk of surgical procedures in obese women, which may account for the lower prevalence in women with BMI > 40. 15 20 25 30 35 40
BMI
Relationship between BMI and crude percentage of women reporting
medical problems, surgical procedures, symptoms, and health care utilization.
Brown WJ et al. Int J Obes 1998;22:
BACKGROUND V

43. Back Pain 35 30
Percentage 25 20
Back pain is described in the study by Brown and colleagues as increasing with higher BMI. This trend curve shows the relationship between BMI and back pain.
There is a 40% increase in the odds ratio of back pain between women with BMI < 20 and women with BMI > 40.
Back pain is one of the most common symptoms reported by women in studies of health concerns. 15 20 25 30 35 40
BMI
Relationship between BMI and crude percentage of women reporting
medical problems, surgical procedures, symptoms, and health care utilization.
Brown WJ et al. Int J Obes 1998;22:
BACKGROUND V

44. Constant Tiredness Percentage BMI35 30
Percentage 25 20
The percentage of women reporting constant tiredness in the study by Brown and colleagues increases with increasing body mass index. This graph shows the trend curve estimated to show the relationship between BMI and constant tiredness.
There is a J-curve associated with tiredness. Women with BMI < 20 report higher feelings of tiredness than those with BMI between 20 and 30, and are almost equivalent to those with BMI between 30 and 40.
There is a 70% increase in odds ratio between women with BMI < 20 and those with BMI > 40. 15 20 25 30 35 40
BMI
Relationship between BMI and crude percentage of women reporting
medical problems, surgical procedures, symptoms, and health care utilization.
Brown WJ et al. Int J Obes 1998;22:
BACKGROUND V

45. More Than Three Specialist Consultations10 8
Percentage 6 4
Brown and colleagues found that consultations with general practitioners and visits to specialists increased with increasing BMI among women. The next two slides show this relationship.
Among women there is a trend curve estimated to show the relationship between BMI and specialist consultations.
The percentage of reported specialist consultations showed a J-curve relationship with BMI.
The lowest utilization of specialists occurred with a BMI of 24 to 25. 2 20 25 30 35 40
BMI
Relationship between BMI and crude percentage of women reporting
medical problems, surgical procedures, symptoms, and health care utilization.
Brown WJ et al. Int J Obes 1998;22:
BACKGROUND V

46. More Than Five GP Consultations30 25
Percentage 20 15
Brown and colleagues reviewed utilization of general practitioners by women and found a J-curve trend with increasing BMI.
Low BMI was associated with fewer physical health problems than mid-level or higher BMI.
Indicators of health care use showed a J-shaped relationship with BMI for general practitioners.
Prevalence of medical problems (for example, hypertension and diabetes), surgical procedures (cholescystectomy, hysterectomy) and symptoms (for example, back pain) increased monotonically with BMI.
This study provides strong support for the recommended BMI range of was an appropriate target for the promotion of healthy weight in middle-aged Australian women. 10 20 25 30 35 40
BMI
Relationship between BMI and crude percentage of women reporting
medical problems, surgical procedures, symptoms, and health care utilization.
Brown WJ et al. Int J Obes 1998;22:
BACKGROUND V

47. Relationship of BMI to Excess Mortality
300
Age at Issue
20-29
250
30-39
200
Mortality Ratio
150
100
Low
Moderate
High
A paper by George Bray examined the relationship of BMI to excess mortality.
Data was pooled from 5 prospective studies (3 industrial and 2 community) and included a total sample of 8,422 white males with a mean length of followup of 8.6 years.
This slide points out the relationship of BMI to excess mortality. There is a curvilinear increase in excess mortality with rising BMI. The risk is low with a BMI of 25 to30 and increases as BMI increases. The greatest risk is seen with BMIs above 40. 50
Risk
Risk
Risk 15 20 25 30 35 40
Body Mass Index (kg/[m2])
Bray GA. Overweight is risking fate. Definition, classification,
prevalence and risks. Ann NY Acad Sci 1987;499:14-28.
BACKGROUND IV

48. Background
Approximately 108 million American adults are overweight or obese.
Increased risk of:
Hypertension
Type 2 diabetes
Coronary heart disease
Gallbladder disease
Certain cancers
Dyslipidemia
Stroke
Osteoarthritis
Sleep apnea
Based on the 1999 NHANES data, about 61 percent of adults, or an estimated 108 million adults, in the United States are overweight or obese, a condition that substantially increases their risk for hypertension, dyslipidemia, type 2 diabetes, stroke, coronary heart disease, osteoarthritis, gallbladder disease, sleep apnea and respiratory problems, and endometrial, breast, prostate, and colon cancers.
Higher body weight is also associated with increases in all-cause mortality.
Obese individuals may also suffer from social stigmatization and discrimination.
CDC/NCHS NHANES 1999
CORE SET I

49. Body Fat and Its Distribution
Fat distribution
Intra-abdominal fat
Central obesity

50. Body Fat and Its Distribution
Fat distribution is determined by waist to hip ratio
Intra-abdominal fat
Waist:Ratio < .8 ♀ or .95 ♂
Central obesity
Waist:Ratio > .8 ♀ or .95 ♂

51. Body Fat and Its Distribution
For both men and women, a waist-to-hip ratio of 1.0 or higher is considered "at risk" or in the danger zone for undesirable health consequences, such as heart disease and other ailments connected with being overweight.
A ratio of .90 or less is considered safe. This means that your waist is 90% of your hips...so you can do your belt up tighter around your waist than your hips.

52. Body Fat and Its Distribution

53. Body Fat and Its Distribution
Fatfold measure

54. Body Fat and Its Distribution
Hydrodensitometry

55. Body Fat and Its Distribution
Bioelectrical impedance

56. Body Fat and Its Distribution
Air displacement plethysmography

57. Body Fat and Its Distribution
Dual energy X-ray absorptiometry (DEXA)

58. Methods Used to Assess Body Fat

59. Health Risks Associated With Body Weight and Body Fat
Health risks of underweight
Health risks of overweight

60. Health Risks Associated With Body Weight and Body Fat
Health risks of underweight
May be associated with poor nutrition (smoking, substance abuse, illness)
Wasting diseases or medical stress
Infertility

61. Health Risks Associated With Body Weight and Body Fat
Health risks of overweight
Diabetes
Hypertension
Cardiovascular disease
Sleep apnea
Cancer
Gall bladder disease
Respiratory ptoblems

62. BMI and Mortality

63. It’s The Calories Stupid
Your body can convert all macronutrients to fat.
3000 calories equals a pound, no matter how the macronutrient is consumed.