PDA-assisted low glycemic index dietary intervention for type II diabetes: a pilot study.

BACKGROUND: Epidemiological and dietary intervention studies suggest that a low-glycemic index (GI) diet is beneficial for blood glucose control; however, long-term clinical utility of the low GI diet has not been fully investigated. OBJECTIVES: To evaluate the feasibility and efficacy of a nutritionist-delivered low-GI dietary intervention, with the support of a personal digital assistant (PDA), for adult patients with poorly controlled type II diabetes. METHOD: The low-GI intervention consisted of six counseling sessions and the use of a PDA-based food database with GI scores for 6 months. Study outcomes included feasibility measures, glycosylated hemoglobin levels (HbA1c), GI and glycemic load (GL) score of self-reported dietary intake, body weight, depression and quality of life (QOL). Measures were obtained at baseline, 3 and 6 months. RESULTS: Of 31 adult patients approached, 15 met study eligibility criteria and were enrolled in the study. Thirteen patients (87%) completed all study assessments. Findings included decreases in average HbA1c (-0.5% P = 0.02), body weight, hip circumference, blood pressure, dietary GI and daily caloric intake. Diabetes impact scores also decreased. All but one participant completed all components of the intervention. There were mixed reports regarding the usefulness of the PDAs; however, participants offered helpful suggestions for further development. CONCLUSIONS: Results of this pilot study support the feasibility of implementing a nutritionist-delivered, PDA-assisted low-GI dietary intervention for patients with poorly controlled type II diabetes. Encouraging initial efficacy data require further testing in the context of a randomized clinical trial.

Seasonal variation in food intake, physical activity, and body weight in a predominantly overweight population.

OBJECTIVE: To describe seasonal variation in food intake, physical activity, and body weight in a predominantly overweight population. DESIGN: A longitudinal observational study. SETTING: Most of the study participants were recruited from a health maintenance organization (HMO) in central Massachusetts, USA. Additional individuals of Hispanic descent were recruited from outside of the HMO population to increase the ethnic diversity of this sample. SUBJECTS: Data from 593 participants, aged 20-70, were used for this investigation. Each participant was followed quarterly (five sampling points: baseline and four consecutive quarters) for 1-year period. Body weight measurements and three 24-h dietary and physical activity recalls were obtained on randomly selected days (including 2 weekdays and 1 weekend day) per quarter. Sinusoidal regression models were used to estimate peak-to-trough amplitude and phase of the peaks. RESULTS: Daily caloric intake was higher by 86 kcal/day during the fall compared to the spring. Percentage of calories from carbohydrate, fat and saturated fat showed slight seasonal variation, with a peak in the spring for carbohydrate and in the fall for total fat and saturated fat intake. The lowest physical activity level was observed in the winter and the highest in the spring. Body weight varied by about 1/2 kg throughout the year, with a peak in the winter (P<0.001 winter versus summer). Greater seasonal variation was observed in subjects who were male, middle aged, nonwhite, and less educated. CONCLUSIONS: Although there is seasonal variation in diet, physical activity and body weight, the magnitude of the change is generally small in this population. SPONSORSHIP: US National Heart, Lung and Blood Institute.