Fitness vs. Fatness Debate

Eric.Ravussin@pbrc.edu

China Medical University, Lifu Teaching BuildingTaichung, Taiwan; April26 th 2011

Obesity Facts

Over 66% of Americans are overweight or obese Number of Obese American adults rose to 33%

Over last decade alone an increase of 12% - overweight 70% - obese

Occurred for all population subsets: children, elderly & all racial/ethnic groups

Second leading cause of preventable death

Over 280,000 – 325,000 obesity related deaths annually (including co-morbidities)

Trust for America’s Health Facts 2005http://www.cdc.gov/pcd/issues/2005/jan/04_0087.htm

NHANES 1976-1980NHANES 1999-2004

1976-1980 32.1 ± 0.6 15.0 ± 0.4 1.4 ± 0.1

2003-2004 33.4 ± 1.2 32.9 ± 1.3 5.1 ± 0.6

BM

I d

istr

ibu

tio

n (

%)

Overweight Obese Extremely Obese

Redman & Ravussin 2008

Traditional Environment

Leptogenic Environment

Social Environment Built Environment

Obesogenic Environment

1900s 2000s

“Leptogenic” environment

“Obesogenic”environment

BMI (kg/m )2

Genetics

Environment

Genetics

Obesity Resistant Obesity Prone

Obesity Susceptibility Obesity Susceptibility

Redman & Ravussin 2008

Obesity Epidemic: Reduced Physical Activity and/or Increased Energy Intake?

Fitness vs. Fatness Debate

Exercise for Weight Loss or Weight Maintenance?

Fitness vs. Fatness Debate

Estimates of Increased Energy Intake Since the 1970’s

Agency Men Women

CDC 2004 168 kcal/d 335 kcal/d

USDA CSFII 268 kcal/d 143 kcal/d

Author Energy for Wt Gain

Hill et al 2000 100 kcal/d

Gortmaker et al 2006 150-175 kcal/d

Hill JO et al Science 2003;299:853-855Wang YC et al Pediatrics 2006;118:1721-1733

Energy Intake 1910-2000

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

1900 1920 1940 1960 1980 20002000

2200

2400

2600

2800

3000

3200

3400

3600

3800

4000

Year

En

erg

y (k

cal/

d)

Corrected for Waste

Total Consumption – Uncorrected for waste

4000

3800

3600

3400

3200

3000

2800

2600

2400

2200

2000 1900 1920 1940 1960 1980 2000

Year

0

30

Time A Time B

En

erg

y fl

ux

(dai

ly T

EI

and

TE

E)

‘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

Some Assumptions and Consequences

Assumptions En In = En Out = En Flux at ‘settling point’ People are in virtual energy balance: “Energy

Imbalance Gap” is very small

Consequences “Energy Flux Gap” is large (US ~120kcal/day

decade) Population needs big changes to reverse to

1970s levels (~400kcal/day)

Total EE in Adults

TEE, TEI and body weight are inter-related

Trend towards an equilibrium

Usual relationship is displayed with weight as the independent variable

x Female

O Male

Body weight (kg)

To

tal E

ner

gy

Exp

end

itu

re (

TE

E)

(kJ/

d)

Swinburn, et al AJCN 2009 Jun;89:1723-8

Energy Flux and Weight

Reverse the axes Log the data β=0.71 (not the

reciprocal if axes reversed)

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

x Female

O Male

Ln EnFlux (Ln kJ/d)

Ln

Bo

dy

Wei

gh

t (L

nkg

)

Swinburn, et al AJCN 2009 Jun;89:1723-8

-15

-10

-5

0

5

10

15

-20 -15 -10 -5 0 5 10 15 20

% change in energy flux (where TEI=TEE)

% c

hang

e in

wei

ght

B

•

• C

• A

D•

• E

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

Swinburn, Sacks & Ravussin AJCN 2009

Is the epidemic due to ↑EI or ↓PA?

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

NHANES changes in weight for adults and children

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

Weig

ht

incr

ease

↓PA ↑EIMixture

Slope Adults 0.71

Children 0.43

Swinburn, Sacks & Ravussin AJCN 2009

‘Measured’ vs. Predicted Changes

Weight from

NHANES, EnFlux from USDA

Weight predicted

from equations at USDA EnFlux

Swinburn, Sacks & Ravussin AJCN 2009

Summary and Issues

Terminology and values for the ‘energy gaps’

Increased energy intake has been the major drive of the epidemic Stopping the epidemic Returning to 1970s level

Need behavioural interventions and environmental interventions

Distinguish the drivers (EI) vs. the modulators (physiology, genetics...)

Obesity Epidemic: Reduced Physical Activity and/or Increased Energy Intake?

Fitness vs. Fatness Debate

Exercise for Weight Loss or Weight Maintenance?

Fitness vs. Fatness Debate

0

5

10

15

20

25

30

35

40

45

Rel

ativ

e R

isk

<21 21-22.9

23-24.9

25-26.9

27-29.9

30-32.9

33-34.9

35-39.9

40

BMI

Risk of Developing Diabetes & BMI:Risk of Developing Diabetes & BMI:Nurses Health Study (n= 68,907)Nurses Health Study (n= 68,907)

Rana et al Diab Care Jan 2007

Aerobics Center Longitudinal Aerobics Center Longitudinal Study DatabaseStudy Database

• Dr. Steve Blair & Dr Tim Church

• Consists of Cooper Clinic patients– >70,000 individuals enrolled

• Examinations dating back to 1970

• Follow-up for mortality and morbidity – every 3-4 years

Fitness TestingFitness Testing

• Maximal exercise test on a treadmill (Balke)

• Standardized fitness categories based on age, gender & time on treadmill:

• Fitness => measure of physical activity habits

Fitness ClassificationsFitness Classifications

• Low Fitness = “Unfit”– Lower 20% time on treadmill for gender and age

• Moderate Fitness-– Next 40% time on treadmill for gender and age

– @150 minutes of walking per week

• High Fitness-– Highest 40% time on treadmill for gender and age

Diabetes Diabetes Incidence Rates Incidence Rates By By Fitness Groups, Men (n=8633)Fitness Groups, Men (n=8633)

5.9

2.7

1.6

0

1

2

3

4

5

6

7

Low Moderate High

Wei M et al. Ann Int Med 1999

Cardiorespiratory Fitness Groups

Dia

bete

s in

cide

nce/

1000

men

0

5

10

15

20

25

30

35

40

45

Rat

e p

er 1

,000

man

-yrs

<8.0 8.0-8.9

9.0-9.9

10.0-10.9

11.0-11.9

12.0-12.9

13.0-13.9

14.0-14.9

≥15.0

Maximal METs

Diabetes Incidence Rates by Diabetes Incidence Rates by Fitness: ACLS (n =13,190)Fitness: ACLS (n =13,190)

P trend < 0.0001

unpublished

Risk of Diabetes By Risk of Diabetes By Physical Activity-Fatness - NHSPhysical Activity-Fatness - NHS

02468

1012141618

Normal Overweight Obese

Ris

k o

f D

iab

ete

s

<2.1 2.1-4.6 4.7-10.4 10.5-21.7 >21.7

MET hours per week

Rana et al Diab Care Jan 2007

Risk of Diabetes By Risk of Diabetes By Physical Activity-Fatness - NHSPhysical Activity-Fatness - NHS

02468

1012141618

Normal Overweight Obese

Ris

k o

f D

iab

ete

s

<2.1 2.1-4.6 4.7-10.4 10.5-21.7 >21.7

MET hours per week

Rana et al Diab Care Jan 2007

Supported by Numerous Other

Studies

CVD Mortality by Fitness CVD Mortality by Fitness Men with Diabetes Men with Diabetes

Church et al, Arch Int Med, 2005

0

20

40

60

80

100

120

140

160

<7 7 to 7.9 8 to 8.9 9 to 9.9 10 to10.9

11 to11.9

12 to12.9

>13

Mets

CV

D D

eath

Rat

e (p

er 1

0K m

an-y

ear)

0.6

0.65

0.7

0.75

0.8

0.85

0.9

0.95

1

0 5 10 15 20 25 30

Su

rviv

al R

ate

(%)

Low Fitness

Moderate Fitness

High Fitness

Fitness & Risk CVD in Fitness & Risk CVD in Individuals with Individuals with

DiabetesDiabetes

Church et al, Arch Int Med, 2005

0.7

0.75

0.8

0.85

0.9

0.95

1

0 5 10 15 20 25 30

Su

rviv

al R

ate

(%)

18.5 - 24.9 kg/m2

25.0 - 29.9 kg/m2

30.0 - 34.9 kg/m2

0.7

0.75

0.8

0.85

0.9

0.95

1

0 5 10 15 20 25 30

Su

rviv

al R

ate

(%)

Low Fitness

Moderate Fitness

High Fitness

Church et al, Archives of Internal Medicine, 2005

Fit-Fat & Risk CVD in Fit-Fat & Risk CVD in Individuals with DiabetesIndividuals with Diabetes

CVD Mortality Risk by CVD Mortality Risk by Fitness-Fatness: Men with DMFitness-Fatness: Men with DM

0

1

2

3

4

5

Normal Overweight Obese

Ris

k o

f C

VD

Dea

th

Low Mod High

Church et al, Archives of Internal Medicine, 2005

CVD Mortality Risk by Fitness-CVD Mortality Risk by Fitness-Fatness: Men with DMFatness: Men with DM

0

1

2

3

4

5

Low Mod High

Ris

k o

f C

VD

Dea

th

Normal Over Obese

Fitness

Church et al, Archives of Internal Medicine, 2005

FitnessFitness

CVDCVDDMDM

Weight Weight WeightWeight

FitnessFitness

FitnessFitness

CVDCVDDMDM

WeightWeightWeightWeight

FitnessFitness

X

SummarySummary

• Obesity increases risk of diabetes

– Independent of physical activity

– Appears to be more important than PA

• Obesity increases risk of CVD

– Negated when fitness is accounted for

How does fitness protect How does fitness protect overweight/obese individuals overweight/obese individuals

with diabetes from CVD?with diabetes from CVD?

Exercise is PleiotropicExercise is PleiotropicPhysiological Benefits

Improved heart rate variability Reduced systemic inflammation

Reduced blood pressure Improved insulin sensitivity

Improved endothelial function Decreased myocardial oxygen demand

Increased myocardial function Maintains lean mass

Decreased platelet aggregation Increased fibrinolysis

Reduced blood and plasma viscosity Increased capillary density

Increased mitochondrial density Reduced visceral adiposity

Better sleep Improved mood and reduced anxiety

Reduced risk of developing…….Hypertension Osteoporosis

Metabolic syndrome Osteoarthritis

Depression Breast and colon cancer

Type 2 diabetes Dementia and Alzheimer’s disease

0

5

10

15

20

25

30

35

40

45

Rat

e p

er 1

,000

man

-yrs

<8.0 8.0-8.9

9.0-9.9

10.0-10.9

11.0-11.9

12.0-12.9

13.0-13.9

14.0-14.9

≥15.0

Maximal METs

P trend < 0.0001

Why ?

Diabetes Incidence Rates by Diabetes Incidence Rates by Fitness: ACLS (n =13,190)Fitness: ACLS (n =13,190)

Fitness and All-Cause Mortality, ACLS Men, 1970-1989

0

50

100

150

200

250

300

0 5 10 15 20 25 30

GXT Test Performance (minutes)

Ad

just

ed

Death

Rate

per

10

,00

0 P

Y

95% Upper Limit

Adjusted Death Rate

95% Lower Limit

Expected RelationExpected Relation

Fitness and All-Cause Mortality, ACLS Men, 1970-1989

0

50

100

150

200

250

300

0 5 10 15 20 25 30

GXT Test Performance (minutes)

Ad

just

ed

Death

Rate

per

10

,00

0 P

Y

95% Upper Limit

Adjusted Death Rate

95% Lower Limit

Expected Relation

Obesity Epidemic: Reduced Physical Activity and/or Increased Energy Intake?

Fitness vs. Fatness debate

Exercise for Weight Loss or Weight Maintenance?

Fitness vs. Fatness Debate

30 minutes

Prevalence of people in each state meeting current public health physical activity recommendations

US Centers for Disease Control and Prevention (2005)

5 days a week for 30 min/d moderate intensity activity or at least 3 days a week for 20 min/d of vigorous intensity activity or the equivalent of 1,000 kcal/wk in activity

Exercise-Induced Weight Loss

Reduction in Obesity and Related Comorbid Conditions after Diet-Induced Weight Loss or Exercise-Induced Weight Loss in Men (N=52; 3 mo; 700kcal/d) (R Ross et al Ann Int Med 2000; 92-103)

Exercise-Induced Redduction in Obesity and Insulin Resistance in Women: a RCT (N=54; 14-wk; 500Kcal/d) (R Ross et al; Obes Res 2004; 789-98)

Effect of a 16-m Randomized Controlled Exercise Trial on Body Weight and Composition in Young Overweight Men and Women (N=74; 16 mo; 400 kcal/d for 5 days) (JE Donnelly et al; Ann Int Med 2003; 1343-50)

Effect of Calorie Restriction with or without Exercise on Body Composition and Fat Distribution (LM Redman et al; JCEM 2007; 875-82)

Study Overview

Ran

do

miz

atio

n

25% CR (n=12)

12.5% CR + 12.5% EX (n=12)

Baseline (n=36)

Healthy Diet Control (n=12)

Weeks -5 -3 0 12 24

Food Provided Food at Home FP

Body composition – DXA

Abdominal Fat – Multi slice CT

Aerobic Capacity – VO2peak (treadmill)

Fasting lipids

Insulin Sensitivity – MinMod (Bergman)

Caloric PrescriptionEnergy Requirement for weight maintenance

2 x 14d Doubly Labeled Water

Dai

ly E

nerg

y R

equi

rem

ent

100

75

Energy Deficit

Dietary Restriction only

CR

Dietary Restriction

Aerobic Exercise

Energy Deficit

CR+EX

+

Healthy Diet

Control

~ 10%

Body Mass Change

Weeks

2 4 6 8 10 12 14 16 18 20 22 24

Wei

gh

t c

ha

ng

e (

%)

-10

-8

-6

-4

-2

0

2

Control CR+EXCR

No difference between CR and CR+EX

*

* Significant change from baseline

Body Fat Change

Control CR CR+EX-40

-30

-20

-10

0

Per

cent

cha

nge

in F

M

CONTROL CR CR+EX-40

-30

-20

-10

0

Per

cent

cha

nge

in V

AT

Fat Mass by DXA

Visceral Fat by CT

* ** *

No difference between CR and CR+EX

* Significant change from baseline

National Weight Control Registry

(av. Wt loss 30kg for 5 years)

Eat a diet low in fat

Self monitoring of weight and food intake

Very high level of physical activity

Physical Activity Recommendations (CDC)

Current physical activity recommendations call for 30 minutes of moderate intensity activity on most days of the week, or the equivalent of expending approximately 1,000 kcal in activity per week

The Role of Physical Activity in Maintaining a Reduced Weight (Johannsen DL & Ravussin, Curr Athero Rep 2007)

Reduction in chronic disease and all-cause mortality with current recommendations of 30 min per day (1000 Kcal/wk)

60-90 min/d of moderate activity is necessary to maintain a reduced weight (2600-2800 Kcal/wk)

Energy Expenditure in Physical Activity for Maintenance of Weight

Loss

The new challenge is living better longer

The challenge is not living longer……

Dr Cefalu is on his way for a long healthy life but …. It is hard work