Dose-Dependent Associations of Dietary Glycemic Index, Glycemic Load, and Fiber With 3-Year Weight Loss Maintenance and Glycemic Status in a High-Risk Population: A Secondary Analysis of the Diabetes Prevention Study PREVIEW
To examine longitudinal and dose-dependent associations of dietary glycemic index (GI), glycemic load (GL), and fiber with body weight and glycemic status during 3-year weight-loss maintenance (WLM) in high-risk adults.
RESEARCH DESIGN AND METHODS
This secondary analysis used pooled data from the PREVIEW randomized controlled trial, which was designed to test the effects of four diet and physical activity interventions. 1,279 participants with overweight or obesity (aged 25–70 years; BMI≥25 kg·m-2) and pre-diabetes at baseline were included. Multi-adjusted linear mixed models with repeated measurements were used to assess longitudinal and dose-dependent associations, by merging the participants into one group and dividing them into GI, GL, and fiber tertiles, respectively.
In the available-case and complete-case analyses, each 10-unit increment in GI was associated with a greater regain of weight (0.46 kg·year-1; 95% CI 0.23, 0.68; P<0.001) and increase in HbA1c. Each 20-unit increment in GL was associated with a greater regain of weight (0.49 kg·year-1; 0.24, 0.75; P<0.001) and increase in HbA1c. The associations of GI and GL with HbA1c were independent of weight change. Compared with those in the lowest tertiles, participants in the highest GI and GL tertiles had significantly higher weight regain and increases in HbA1c. Fiber was inversely associated with increases in waist circumference, but the associations with weight regain and glycemic status did not remain robust in different analyses.
Dietary GI and GL were positively associated with weight regain and deteriorating glycemic status. Stronger evidence on the role of fiber is needed.