Physiology of Energy Expenditure
This presentation is the property of its rightful owner.
Sponsored Links
1 / 46

Physiology of Energy Expenditure Eric Ravussin [email protected] PowerPoint PPT Presentation


  • 109 Views
  • Uploaded on
  • Presentation posted in: General

Physiology of Energy Expenditure Eric Ravussin [email protected] DRUGS?. ENVIRONMENT. ACTIVITY?. Physical Environment. Energy Partitioning Fat Accretion. Obesity. Behaviors. Social Environment. Overweight. Adipogenesis. Biology. Energy Intake. Energy Expenditure.

Download Presentation

Physiology of Energy Expenditure Eric Ravussin [email protected]

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Physiology of energy expenditure eric ravussin eric ravussin pbrc edu

Physiology of Energy Expenditure

Eric Ravussin

[email protected]

DRUGS?

ENVIRONMENT

ACTIVITY?


Physiology of energy expenditure eric ravussin eric ravussin pbrc edu

Physical Environment

Energy

Partitioning

Fat

Accretion

Obesity

Behaviors

Social Environment

Overweight

Adipogenesis

Biology

Energy Intake

Energy Expenditure

Bouchard and Rankinen, 2007


Physiology of energy expenditure eric ravussin eric ravussin pbrc edu

Obesogenic Behavior

Obesogenic Environment

Energy

Partitioning

Fat

Accretion

Obesity

Overweight

Adipogenesis

Social Environment

Built Environment

Biology

Energy Intake

Energy Expenditure


Physiology of energy expenditure eric ravussin eric ravussin pbrc edu

Obesogenic Environment

Environment

Genetics

2

“Leptogenic”

BMI (kg/m )

“Obesogenic”

environment

environment

Traditional Environment

Social Environment

Built Environment

1900s

2000s

Leptogenic Environment

Obesity Susceptibility

Obesity Susceptibility

Genetics

Obesity Resistant

Obesity Prone

Redman & Ravussin 2008


Walk the dog and keep fit the american way

Walk the dog and keep fit“The American way”


Physiology of energy expenditure eric ravussin eric ravussin pbrc edu

NHANES 1976-1980

NHANES 1999-2004

BMI distribution (%)

Obese

Overweight

Extremely Obese

Redman & Ravussin 2008


Putative contributors to the secular increase in obesity besides more food and less activity

Putative Contributors to the Secular Increase in Obesity Besides more Food and less Activity

25

17.3

67.5

.50

32

26

80

67

4000

80

24

17.2

79

31

25.75

66.5

.49

79

3750

78

23

17.1

66

30

25.5

.48

77

78

65.5

3500

22

17

25.25

29

76

65

.47

77

25

28

21

16.9

3250

75

64.5

74

76

.46

24.75

27

64

20

16.8

3000

73

63.5

24.5

75

26

.45

19

16.7

72

2750

63

24.25

25

74

71

18

.44

62.5

16.6

2500

24

24

70

62

73

17

16.5

.43

Adult obesity prevalence (%)

69

Antidepressant prescriptions (millions)

2250

Nonsmoker prevalence (%)

23.75

23

61.5

Prevalence of AC (%)

PBDE concentration (pg/g)

Average home temperature (F)

72

Time spent awake (hours/day)

Mean age of mothers at first birth (years)

68

16

16.4

61

.42

Proportion Hispanic and/or aged between 35 and 55 years

23.5

22

2000

67

71

60.5

15

16.3

23.25

21

.41

66

60

1750

70

23

14

16.2

65

20

59.5

.40

1500

69

64

59

22.75

19

13

16.1

63

.39

58.5

1225

68

22.5

18

12

16

62

58

.38

22.25

67

17

1000

61

57.5

11

15.9

22

60

16

57

66

.37

750

10

15.8

59

56.5

21.75

15

65

.36

500

58

56

9

15.7

21.5

14

64

57

55.5

.35

250

8

15.6

21.25

13

56

55

63

55

0

7

21

.34

15.5

12

54.5

1960

1965

1970

1975

1980

1985

1990

1995

2000

Prevalence of AC (%)

Nonsmoker prevalence (%)

Year

Adult obesity prevalence (%)

Proportion of Hispanicand/or aged between35 and 55 years

Mean age of mothers at firstbirth (years)

Average home temperature (F)

Antidepressant prescriptions(millions)

PBDE concentration (pg/g)

Time spent awake(hours/day)

Keith SW et al. Int J Obes. 2006;30:1585-1594; and McAlister et al., Crit Rev in Food Sci & Nutr, 2009.


Physiology of energy expenditure eric ravussin eric ravussin pbrc edu

Long-term Weight Homeostasis Principles of Energy Balance

1 % e r r o r =  1 kg / yr


Physiology of energy expenditure eric ravussin eric ravussin pbrc edu

Eucaloric Diet, 2500kcal/d

Energy Stores

> 60,000 kcal

Energy Intake (kcal/day)

Daily Oxidation (% stores)

Carbohydrate

2,000 kcal

1,000

50-100%

NO EFFECT ON ENERGY BALANCE

Protein

40,000 kcal

500

1.3%

NO EFFECT ON ENERGY BALANCE

Fat

125,000 kcal

1,000

<1%

DAILY FAT BALANCE = ENERGY BALANCE

_

+

ENERGY EXPENDITURE

ENERGY INTAKE

The

Energy

Balance


Metabolic characteristics of obese and pre obese individuals

Metabolic Characteristics of Obese and Pre-obese Individuals

  • Relative RMRNormal/HighLow

  • Activity EE CostNormal Low

  • Fat OxidationNormal/HighLow

  • SNS activityNormal/HighLow

  • Relative LeptinConcHighLow

Obese Pre/Post Obese

Cross sectionnal Prospective


Small energy imbalance

Small Energy Imbalance

  • 70kg adult

  • Add or subtract 50 kcal/d

  • 365 x 50 = 18,250 kcal/y

  • Assume 1 kg fat = 9,000 kcal

Please do not do that. Use dynamic models of Energy Balance:

http://bwsimulator.niddk.nih.gov/ (Kevin Hall at NIDDK)

http://www.pbrc.edu/research-and-faculty/calculators/weight-loss-predictor/

(Diana Thomas)


Participant characteristics

Participant Characteristics

Age: 36 years (20-56 y old)

4 males, 7 females

J ClinEndocrinolMetab. 2012 Apr 24. [Epub


Physiology of energy expenditure eric ravussin eric ravussin pbrc edu

Metabolic adaptation occurred despite lean mass preservation

J Clin End Metab. 2012 Apr 24. [Epub

Week 6

Week 30

Baseline

-244 ± 231

p=0.006

-504 ± 171

p<0.001

Predicted RMR = 1,241 + 19.2 ffm + 1.8 fm – 9.8 age + 405 (male)


Correlation between change in leptin and rmr residual in bl 7 mo and gb 12 mo participants

Correlation between change in leptin and RMR residual in BL (7 mo) and GB (12 mo) participants

Unpublished data


Determinants of the metabolic adaptation

Determinants of the Metabolic Adaptation

CR

↓ leptin

↓ SNS

↓ Gonadal axis

↓ Thyroid hormones

↓ Energymetabolism = metabolic adaptation


Physiology of energy expenditure eric ravussin eric ravussin pbrc edu

‘Energy Imbalance Gap’ = the average difference between daily TEI (top line) and TEE (bottom line) needed to produce weight gain over a period of time

‘Energy Flux Gap’= the average difference in energy flux (TEI ≈ TEE) between two points in time

Period of weight gain

(Settling point A, lower mean weight)

(Settling point B, higher mean weight)

Energy Gap Terminology

Swinburn, et al AJCN, 2009


Some assumptions

Some Assumptions

  • Assumptions

    • En In = En Out = En Flux at stable weight (‘settling point’)

    • People are in virtual energy balance because the Energy Imbalance Gap is very small


Total ee in adults

Total EE in Adults

  • Usual relationship is displayed with weight as the independent variable

  • N=1399 adults from 8 centers (6 US, Netherlands, New Zealand)

Swinburn, et al AJCN, 2009


Energy flux and weight

Energy Flux and Weight

  • Reverse the axes

  • Log the data

  • β=0.71

  • Use some algebra → a 10% difference in En Flux (best thought of as En Intake) → 7% difference in weight (assuming age, gender, height constant)

Swinburn, et al AJCN, 2009


Physiology of energy expenditure eric ravussin eric ravussin pbrc edu

D•

B

•A

C

• E

A=base case, B=↑EI, C=↓EI, D=↓PA, E=↑PA

Swinburn, et al AJCN, 2009


Is the epidemic due to ei or pa

↓PA

Mixture

↑EI

Weight increase

Is the epidemic due to ↑EI or ↓PA?

  • The equations could estimate the proportion of the epidemic due to ↓PA or ↑EI or a mixture

  • NHANES changes in weight for adults and children

  • USDA calorie ‘disappearance’ data (proportioned for adults and children)

Slope

Adults 0.71

Children 0.43


Energy intake 1910 2000

Energy Intake 1910-2000

4000

3800

3600

3400

3200

3000

2800

2600

2400

2200

2000

Total Consumption – Uncorrected for waste

Energy (kcal/d)

Corrected for Waste

1900 1920 1940 1960 1980 2000

Year

USDA/ERS Food Review 2002;25:2-15


Physiology of energy expenditure eric ravussin eric ravussin pbrc edu

Estimated changes in daily average energy intake per capita (MJ/d) for US children and adults from the 1970s to the 2000s

500 Kcal/d

354 Kcal/d

Estimated Total Energy Intake

per capita (MJ/d)

Swinburn, Sacks and Ravussin, AJCN, 2009


Physiology of energy expenditure eric ravussin eric ravussin pbrc edu

Relationship Between the “Energy Flux”

And Body Weight

Mean population weight in 2000s

Mean population weight in 1970s

Body Weight (Ln kg)

Energy Flux = Energy Intake (Ln kJ/d)

Swinburn, Sacks and Ravussin, AJCN, 2009


Measured versus predicted changes

‘Measured’ versus predicted changes

Swinburn, Sacks and Ravussin, AJCN, 2009

2000s

Weight from NHANES, EnFlux from USDA

1970s

2000s

Weight predicted from equations at USDA EnFlux

1970s


Some consequences

Some Consequences

  • Consequences

    • Energy Flux Gap is large (~350 – 500 kcal/day over 30 years)

    • Population needs big changes to reverse to 1970s levels

      • Match Energy Flux Gap ~350kcal/d in children and ~500kcal/d in adults

      • This has all to be achieved against the “drivers” of the environment


Conclusions

Conclusions

Observed weight gain is virtually all attributable to increased energy intake

Reverse energy intake by approximately 500 kcal/d for adults and 350 kcal/d for children

Increase physical activity by 110-150 min/d of walking

Combination is needed to return to the 1970s


Physiology of energy expenditure eric ravussin eric ravussin pbrc edu

Current Employment Statistics (CES)

Current Population Survey (CPS)

Church T et al, PLoS One. 2011;6: e19657


Farming jobs in us

Farming Jobs in US

Church T et al, PLoS One. 2011;6: e19657


Goods producing jobs manufacturing construction mining logging

Goods Producing Jobs:Manufacturing, Construction & Mining/Logging

Church T et al, PLoS One. 2011;6: e19657


Jobs in u s over last 50 years

Jobs in U.S. Over Last 50 Years

Church T et al, PLoS One. 2011;6: e19657


Service jobs

Service Jobs

Church T et al, PLoS One. 2011;6: e19657


Physiology of energy expenditure eric ravussin eric ravussin pbrc edu

Manufacturing vs. Obesity

Church T et al, PLoS One. 2011;6: e19657


Physiology of energy expenditure eric ravussin eric ravussin pbrc edu

Energy Cost of Different Professional Activities


Physical activity intensity

Physical Activity Intensity

Church T et al, PLoS One. 2011;6: e19657


Sedentary light to moderate intensity jobs

Sedentary & Light to Moderate Intensity Jobs

Church T et al, PLoS One. 2011;6: e19657


Mean occupational daily mets

Mean Occupational Daily METs

Church T et al, PLoS One. 2011;6: e19657


Daily occupational caloric expenditure

Daily Occupational Caloric Expenditure

-140 kcal/day

-120 kcal/day

Church T et al, PLoS One. 2011;6: e19657


Summary

Summary

  • Over the last 50 years……..

    • There has been a progressive shift from labor intensive manufacturing jobs to sedentary service related jobs

    • This has resulted in a loss of ……

      • 140 kcal/day for men

      • 120 kcal/day for women

  • This reduction in work related energy expenditure may explain some of the weight gain in the US population over the past 50 years


Physiology of energy expenditure eric ravussin eric ravussin pbrc edu

Thank you / Questions?


  • Login