Public Health Nutrition

Research Paper

A randomized behavioural trial targeting glycaemic index improves dietary, weight and metabolic outcomes in patients with type 2 diabetes

Melissa Davis Gutschalla1 p1, Carla K Millera2 p2 c1, Diane C Mitchella3 and Frank R Lawrencea4

a1 Department of Nutritional Sciences, Pennsylvania State University, University Park, PA 16802, USA

a2 Penn State Diabetes Center, Pennsylvania State University, University Park, PA 16802, USA

a3 Diet Assessment Center, Department of Nutritional Sciences, Pennsylvania State University, University Park, PA 16802, USA

a4 Department of Human Development and Family Studies, Pennsylvania State University, University Park, PA 16802, USA

Abstract

Objective Glycaemic index (GI) reflects the postprandial glucose response of carbohydrate-containing foods. A diet with lower GI may improve glycaemic control in people with diabetes. The purpose of the present study was to evaluate the change in outcomes following a behavioural intervention which promoted lower-GI foods among adults with diabetes.

Design A pre-test–post-test control group design was used with participants randomly assigned to an immediate (experimental) or delayed (control) treatment group. The intervention included a 9-week, group-based intervention about carbohydrate and the glycaemic index. Dietary, anthropometric and metabolic measures were obtained pre/post-intervention in both groups and at 18-week follow-up for the immediate group.

Setting The study was conducted in a rural community in the north-eastern USA.

Subjects Adults having type 2 diabetes mellitus for ≥1 year, aged 40–70 years and not requiring insulin therapy (n 109) were recruited.

Results Following the intervention, mean dietary GI (P < 0·001), percentage of energy from total fat (P < 0·01) and total dietary fibre (P < 0·01) improved in the immediate compared with the delayed group. Mean BMI (P < 0·0001), fasting plasma glucose (P = 0·03), postprandial glucose (P = 0·02), fructosamine (P = 0·02) and insulin sensitivity factor (P = 0·04) also improved in the immediate group compared with the delayed group. Mean waist circumference among males (P < 0·01) and body weight among males and females (P < 0·01) were significantly different between treatment groups.

Conclusions Educating clients about carbohydrate and the glycaemic index can improve dietary intake and health outcomes among adults with type 2 diabetes.

(Received July 11 2008)

(Accepted November 13 2008)

Correspondence

c1 Corresponding author: Email CMiller@ehe.osu.edu

p1 Present address: Department of Foods & Nutrition, Radford University, Radford, VA 24142, USA

p2 Present and correspondence address: Department of Human Nutrition, Ohio State University, 325 Campbell Hall, 1787 Neil Avenue, Columbus, OH 43210, USA

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