Insulin sensitivity determines the effectiveness of dietary macronutrient composition on weight loss in obese women.
OBJECTIVE
To determine whether macronutrient composition of a hypocaloric diet can enhance its effectiveness and whether insulin sensitivity (Si) affects the response to hypocaloric diets.


METHODS
Obese nondiabetic insulin-sensitive (fasting insulin < 10 microU/mL; n = 12) and obese nondiabetic insulin-resistant (fasting insulin > 15 microU/mL; n = 9) women (23 to 53 years old) were randomized to either a high carbohydrate (CHO) (HC)/low fat (LF) (60% CHO, 20% fat) or low CHO (LC)/high fat (HF) (40% CHO, 40% fat) hypocaloric diet. Primary outcome measures after a 16-week dietary intervention were: changes in body weight (BW), Si, resting metabolic rate, and fasting lipids.


RESULTS
Insulin-sensitive women on the HC/LF diet lost 13.5 +/- 1.2% (p < 0.001) of their initial BW, whereas those on the LC/HF diet lost 6.8 +/- 1.2% (p < 0.001; p < 0.002 between the groups). In contrast, among the insulin-resistant women, those on the LC/HF diet lost 13.4 +/- 1.3% (p < 0.001) of their initial BW as compared with 8.5 +/- 1.4% (p < 0.001) lost by those on the HC/LF diet (p < 0.04 between two groups). These differences could not be explained by changes in resting metabolic rate, activity, or intake. Overall, changes in Si were associated with the degree of weight loss (r = -0.57, p < 0.05).


CONCLUSIONS
The state of Si determines the effectiveness of macronutrient composition of hypocaloric diets in obese women. For maximal benefit, the macronutrient composition of a hypocaloric diet may need to be adjusted to correspond to the state of Si.
Cornier
Marc-Andre
MA
Department of Medicine, University of Colorado Health Sciences Center, Denver, CO, USA.
Donahoo
W Troy
WT
Pereira
Rocio
R
Gurevich
Inga
I
Westergren
Rickard
R
Enerback
Sven
S
Eckel
Peter J
PJ
Goalstone
Marc L
ML
Hill
James O
JO
Eckel
Robert H
RH
Draznin
Boris
B
D000328:Adult; D001481:Basal Metabolism; D015992:Body Mass Index; D004038:Diet, Reducing; D004040:Dietary Carbohydrates / Q000008:administration & dosage; D004041:Dietary Fats / Q000008:administration & dosage; D002149:Energy Intake; D004734:Energy Metabolism; D005215:Fasting; D005260:Female; D006801:Humans; D007328:Insulin / Q000097:blood; D007333:Insulin Resistance; D008875:Middle Aged; D009765:Obesity / Q000503:physiopathology / Q000628:therapy*; D016896:Treatment Outcome; D015431:Weight Loss
D004040:Dietary Carbohydrates; D004041:Dietary Fats; D007328:Insulin