GI and Weight: No Difference

[Guest guest]

This was a brand new controlled randomized study. Dr

Willet has been a promoter of the GI. I wonder what he

thinks now.

There was no difference in blood sugar or insulin

levels.

Regard

jeff

American Journal of Clinical Nutrition, Vol. 86, No.

3, 707-713, September 2007

An 18-mo randomized trial of a low-glycemic-index diet

and weight change in Brazilian women1,2,3

Rosely Sichieri, Anibal S Moura, Virginia Genelhu,

Hu and Walter C Willet

Background: Despite interest in the glycemic index

diets as an approach to weight control, few long-term

evaluations are available.

Objective: The objective was to investigate the

long-term effect of a low-glycemic-index (LGI) diet

compared with that of a high-glycemic-index (HGI)

diet; all other dietary components were equal.

Design: After a 6-wk run-in, we randomly assigned 203

healthy women [body mass index (in kg/m2): 23–30] aged

25–45 y to an LGI or an HGI diet with a small energy

restriction. The primary outcome measure was weight

change at 18 mo. Secondary outcomes included hunger

and fasting insulin and lipids.

Results: Despite requiring a run-in and the use of

multiple incentives, only 60% of the subjects

completed the study. The difference in glycemic index

between the diets was 35–40 units (40 compared with

79) during all 18 mo of follow-up, and the

carbohydrate intake from energy remained at 60% in

both groups. The LGI group had a slightly greater

weight loss in the first 2 mo of follow-up (–0.72

compared with –0.31 kg), but after 12 mo of follow-up

both groups began to regain weight. After 18 mo, the

weight change was not significantly different (P =

0.93) between groups (LGI: –0.41 kg; HGI: –0.26 kg). A

greater reduction was observed in the LGI diet group

for triacylglycerol (difference = –16.4 mg/dL; P =

0.11) and VLDL cholesterol (difference = –3.7 mg/dL; P

= 0.03).

Conclusions: Long-term weight changes were not

significantly different between the HGI and LGI diet

groups; therefore, this study does not support a

benefit of an LGI diet for weight control. Favorable

changes in lipids confirmed previous results.