Diabetes Care, Vol 21, Issue 1 2-8, Copyright © 1998 by American Diabetes Association
The effect of short periods of caloric restriction on weight loss and glycemic control in type 2 diabetes
KV Williams, ML Mullen, DE Kelley and RR Wing
Department of Medicine, University of Pittsburgh School of Medicine, Pennsylvania, USA. kvw+@.pitt.edu
OBJECTIVE: To determine whether an intermittent very-low-calorie diet
(VLCD) improves weight loss and glycemic control more than moderate caloric
restriction alone. RESEARCH DESIGN AND METHODS: Individuals with type 2
diabetes (n = 54) who were > or = 20% over ideal body weight
participated in a 20-week behavioral weight control program. Subjects were
randomized to either a standard behavioral therapy (SBT) group or to one of
two VLCD groups. SBT subjects received a 1,500-1,800 kcal/day diet
throughout. Both VLCD groups followed a VLCD for 5 consecutive days during
week 2, followed by either intermittent VLCD therapy for 1 day/week for 15
weeks (1-day) or for 5 consecutive days every 5 weeks (5-day), with a
1,500-1,800 kcal/day diet at other times. RESULTS: Both VLCD groups lost
more weight than the SBT group over the 20 weeks (P = 0.04). Although the
groups did not differ in fasting plasma glucose (FPG) changes at 20 weeks,
more subjects in the 5-day group attained a normal HbA1c when compared with
the SBT group (P = 0.04). This benefit was independent of the effects of
weight loss. The best predictor of overall change in FPG and HbA1c was the
FPG response during the first 3 weeks of the program. CONCLUSIONS: Periodic
VLCDs improved weight loss in diabetic subjects. A regimen with
intermittent 5-day VLCD therapy seemed particularly promising, because more
subjects in this group attained a normal HbA1c. Moreover, the glucose
response to a 3-week period of diet therapy predicted glycemic response at
20 weeks, and it was a better predictor of the 20-week response than
initial or overall weight loss.