weight loss among metabolically healthy obese men and women: harmful or beneficial?
DESCRIPTION
Dr. Peter Janiszewski presents his recent research findings at the 2009 Annual Meeting of the Canadian Society of Exercise Physiology.TRANSCRIPT
Weight loss among metabolically healthy obese men and women: harmful or beneficial?
Peter M. Janiszewski & Robert Ross
School of Kinesiology and Health Studies
Clinical Obesity Treatment Guidelines
Measure BMI and WC
BMI = 25-30 kg/m2 OR WC >102/88 cm
No
Yes Assess Risk
Factors
Periodic Check-up
High BMI or WC AND Risk Factors
No
Yes
5-10 % Weight Loss
Adapted from: NIH-NHLBI (1998) Obesity Research
Clinical Obesity Treatment Guidelines
Measure BMI and WC
BMI ≥ 30 kg/m2
Yes 5-10 % Weight
Loss
Adapted from: NIH-NHLBI (1998) Obesity Research
Metabolically Abnormal Obese (MAO)
~70 % of obese individuals
High BMI High Fat Mass Low Insulin Sensitivity High Triglycerides Low HDL High Diabetes and CVD risk
High BMI High Fat Mass High Insulin Sensitivity Low Triglycerides High HDL Low Diabetes and CVD risk
Metabolically Healthy Obese (MHO)
~30 % of obese individuals
Metabolically Abnormal vs. Metabolically Healthy Obese
Diet-Induced Weight Loss in MAO vs. MHO Women
MAO MHO0
20
40
60
80
100
Karelis et al. (2008) Diabetologia
Pre
Post
↑26.1%
Insu
lin S
ensiti
vity
(μ
mol
/min
/kg
FFM
)
MAO MHO0
20
40
60
80
100
Karelis et al. (2008) Diabetologia
Pre
Post
↑26.1% ↓12.8%
Diet-Induced Weight Loss in MAO vs. MHO Women
Insu
lin S
ensiti
vity
(μ
mol
/min
/kg
FFM
)
Objective
Investigate the effects of exercise- and diet-induced weight reduction on cardiometabolic risk factors among MHO and MAO men and women
Methods
• 109 obese men and women were divided into MHO or MAO based on NCEP-ATP III criteria for metabolic syndrome:
• MHO: ≤ 2 of elevated waist circumference, elevated fasting plasma glucose, elevated triglycerides, low HDL-cholesterol, and elevated blood pressure
• MAO: > 2 of above risk factors
• Participants underwent 3-6 months of aerobic or aerobic/resistance exercise or diet weight-loss intervention.
• Changes in anthropometry, body composition by magnetic resonance imaging, and cardiometabolic risk, including insulin sensitivity by hyperinsulinemic-euglycemic clamp, were assessed.
Men WomenMAO
(n = 20)
MHO
(n = 26)
MAO
(n = 23)
MHO (n = 40)
Age (yr) 53.1 ± 14.8 61.4 ± 11.8 b 46.5 ± 10.7 61.1 ± 12.0 b
Anthropometric Body weight (kg) 98.1 ± 9.4 95.6 ± 12.3 87.1 ± 8.3 a 81.1 ± 11.4 a
BMI (kg/m2) 31.4 ± 2.7 31.0 ± 3.1 32.7 ± 2.9 30.4 ± 3.6 Waist circumference (cm) 109.2 ± 6.0 111.7 ± 8.3 101.7 ± 7.8 a 99.3 ± 8.4 a
Risk Factors Fasting Glucose (mmol/L) 5.3 ± 0.5 4.9 ± 0.5 b 5.5 ± 0.7 4.8 ± 0.4 b
Triacylglycerol (mmol/L) 2.3 ± 0.9 1.4 ± 0.5 b 2.1 ± 0.7 1.3 ± 0.5 b
HDL-cholesterol (mmol/L) 0.8 ± 0.3 1.1 ± 0.2 b 1.1 ± 0.2 a 1.5 ± 0.4 a.b
Insulin sensitivity (mg/kg SM/min)∙ 10.8 ± 3.4 14.9 ± 7.4 b 15.7 ± 7.1 a 22.7 ± 7.0 a,b
Metabolic Syndrome n (%) 20 (100.0) 0 (0.0) 23 (100.0) 0 (0.0)
Results: Subject Characteristics
Data presented as the group means ± SD. Age included as a covariate in analyses.a Significantly different from men (P < 0.05). b Significantly different from at-risk group of same gender (P < 0.05).
MAO MHO MAO MHO60
70
80
90
100
110 PrePost
MAO MHO MAO MHO20
30
40
50 PrePost
Bod
y W
eigh
t (kg
)
Men Women Men Women
Fat M
ass
(kg)
MAO MHO MAO MHO4
4.24.44.64.8
55.25.45.6 Pre
Post
MAO MHO MAO MHO1
1.4
1.8
2.2
2.6 PrePost
Glu
cose
(mm
ol/L
)
Men Women Men Women
TG (m
mol
/L)
* **
* * **
*
* **
Results: Effect of Intervention
* Significantly different from baseline (P<0.05). Analyses controlled for age and treatment modality.
Series105
1015202530354045
Insu
lin S
ensi
tivity
(m
g/kg
∙SM
/min
)
Insu
lin S
ensi
tivity
(m
g/kg
∙SM
/min
)
Series105
1015202530354045
Series105
1015202530354045
Insu
lin S
ensi
tivity
(m
g/kg
∙SM
/min
)
Insu
lin S
ensi
tivity
(m
g/kg
∙SM
/min
)
Series105
1015202530354045
Results: Changes in Insulin Sensitivity
Pre
Pre
Pre
Pre
Post
Post
Post
Post
MHO MenMAO Men
MAO Women MHO women
Series10
5
10
15
20
25
30
Series10
5
10
15
20
25
30
Insu
lin S
ensi
tivity
(m
g/kg
∙SM
/min
)Pre Post
MHO
Insu
lin S
ensi
tivity
(m
g/kg
∙SM
/min
)
Pre Post
MAO
3 Months Diet 3 Months Aerobic Exercise6 Months Resistance/Aerobic Exercise6 Months Aerobic Exercise
Results: Changes in Insulin Sensitivity
Conclusions
• Exercise- or diet-induced weight loss among MHO subjects is not associated with an increase in cardiometabolic risk, but in fact, may lead to further improvements in certain metabolic outcomes (insulin sensitivity)
• While the cardiometabolic benefit may be modest, a 5-10% weight loss among MHO individuals should still be considered an appropriate clinical treatment option
Acknowledgements