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