Exercise and obesity:
prevention and treatment
How effective is exercise?
1
2
BMI and mortality
Sharper, 1997
3
Obesity prevalence in world
BMI > 30
Finucane 2011
Overweight prevalence in world
BMI > 25
4
Finucane 2011
5
Energy balance
6
National Runners’
Study:
18-49 yo: 4769
>49 yo: 2150
Male runners
Cross-sectional
Williams 1997
7
Walking and weight reduction
Richardson, 2008
8
Walking and weight reduction
dose-response relation
Richardson, 2008
9
Caloric reduction +
walking / jogging,
Obese female
10
11
Wadden, 2011
12
Wadden, 2011
13
PA additive to caloric restriction
PA alone insufficient
Chaput, 2011
Diet
intervention
Mozaffarian, 2011
14
15
Diet intervention
Mozaffarian, 2011
16
No diet-PA interaction
Mozaffarian, 2011
Coordinated Approach To Child Health
(CATCH): school vs school+community
OW+OB
↓1.3%
17
OW+OB
↓8.2%
Hoelscher, 2010
Coordinated Approach To Child Health
(CATCH): school vs school+community
18
Hoelscher, 2010
19
NEW Kids Program: multidisciplinary cognitive
behavioral modification in OW/OB child
After > 9
months
Skelton, 2008
Mind, Exercise, Nutrition, Do it
(MEND) :multicomponent community-based
child obesity intervention
Sacher, 2010
20
School-based intervention on energy
balance behaviors: mostly ineffective
Yildirim, 2011
21
22
Change in BW after 12 wk in elderly
Witham 2010
Change in cholesterol after 12 wk in
elderly
23
Witham 2010
24
Shift in energy balance?

10% reduction in body weight is associated
with 20-30% decrease in activity energy
expenditure

independent of time spent in physical activity
Change in balance?
25
Energy expenditure oppose the
altered body weight
26
Liquid diet + prescribed exercise
↓BW  ↓TEE, ↓REE, ↓nonresting (PA) EE
Resenbaum 2003
Decrease BW  increase skeletal
muscle efficiency
27
Resenbaum 2003
Decrease BW  increase skeletal
muscle efficiency
28
Resenbaum 2003
↓energy expenditure in walking after verylow energy diet + walking in obese women
Foster 1995
29
↓energy expenditure in walking after verylow energy diet + walking in obese women
Foster 1995
30
EE during inactivity and MVPA
compensation, but not complete
Garland Jr, 2011
31
32
Monkey
Sullivan, 2010
Subjects who have lost 10% BW at
Year 1
Wadden, 2011
33
Subjects who have lost 10% BW at
Year 1
Wadden, 2011
34
35
‘Set point’ theory

Body has a weight ‘set point’

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Maintenance of reduced or elevated body weight
associated with compensatory changes in energy
expenditure (BMR)
Weight cycling: yo-yo effect

After weight loss, it is regained in relatively
short time
36
Set point and settling points

there is biological (active) control of BW, and also
weight stability (and thus a set point at a healthy
steady state)


in response to eating healthy chow diets
By contrast, this regulation is lost by Western diets


failure of biological control is due mainly to external
factors
In this situation, the set point is replaced by various
settling points that are influenced by energy and
macronutrient intake in order for the body to reach a zero
balance of energy and macronutrients and thus a new and
possibly unhealthy steady state
Muller, 2010
International Association of Study of
Obesity consensus
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37
The current physical activity guideline for adults of 30
minutes of moderate intensity activity daily, preferably all
days of the week, for preventing weight gain or regain this
guideline is likely to be insufficient for many individuals in
the current environment.
Prevention of weight regain in formerly obese individuals
requires 60–90 minutes of moderate intensity activity or
lesser amounts of vigorous intensity activity.
moderate intensity activity of approximately 45-60 minutes
per day is required to prevent the transition to overweight or
obesity.
For children, even more activity time is recommended.
incorporating more incidental and leisure-time activity into
the daily routine
Saris 2003, Jakicic 2005
38
Finkelstein et al, 2004
39
CATCH Program


Coordinated Approach To Child Health
BasicPlus, CATACH BP+community
CATCH program incorporated elements of
social ecological models and Social
Cognitive Theory

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Broader and more community-focused approach
extend school programs to the surrounding
community
Hoelscher et al, 2010
40
Programs to
reduce child
obesity
Hoelscher et al, 2010
41
Results of CATCH programs
Hoelscher et al, 2010
42
Conclusion

Implementation of a community-enhanced
school program can be effective in reducing
the prevalence of child overweight in lowincome student populations
Hoelscher et al, 2010
Meta-analysis of weight change
in 12 months in the elderly
Witham and Avenell, 2010
43
Meta-analysis of change in total
cholesterol in 12 months in elderly
Witham and Avenell, 2010
44
45
Conclusions


Blood lipids, blood pressure, mortality,
morbidity, hospitality, quality of life,
glycemic control only appeared in few
studies and inconclusive
although modest weight reductions were
observed, there is a lack of high-quality
evidence to support the efficacy of weight
loss programs in older people
Witham and Avenell, 2010
Exercise intensity and duration
on weight loss
Church, 2011
46
high human development index
TEE in men
Low-mid human development index
Dugas et al, 2010
47
high human development index
TEE in women
Low-mid human development index
Dugas et al, 2010
48
49
Conclusions


TEE adjusted for weight and age or PAL did
not differ significantly between developing
and industrialized countries
the role of energy expenditure in the cause of
obesity at the population level?
Dugas et al, 2010
50
Factors of TEE
Dugas et al, 2010
51
Factors of physical activity level
Dugas et al, 2010
52
Individual differences

Tremendous variation in responses

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
some lost significant amounts of weight
some actually gaining weight
Partly due to how completely individuals
compensate for exercise with elevated food
intake, which corresponds to their hunger after
exercise.
Hall et al, 2012
53
PA on resting energy expenditure

positive effect of vigorous or moderate PA
on REE in 2 separated phases.


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a large effect that lasts ~2 h
a smaller but more prolonged effect that could
take up to 48 h to return to baseline
excess post-exercise oxygen consumption 6–
15% of the energy expended during an exercise
session, which adds little to TEE.
impact of exercise training on REE is
negligible
Hall et al, 2012
54
Energy balance and weight change

Traditional thinking: 7500 kcal expenditure
equals to 1 kg fat loss


Too optimistic, too simplified
every permanent 10-kcal change in energy
intake/d will lead to an eventual weight
change of 1 pound when the body weight
reaches a new steady state

It will take ~1 year to achieve 50%, and ~3 year
to achieve 95% of this weight loss
Hall et al, 2012
55
Body weight simulator
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http://bwsimulator.niddk.nih.gov
http://www.pbrc.edu/theresearch/tools/weight-loss-predictor