Influence of dietary treatment on the abdominally obese postmenopausal woman

Twenty postmenopausal women with abdominal obesity participated in a weight reduction study. The purpose was to determine the effects of a low and high glycemic index(GI) diet on carbohydrate and lipid metabolism. Subjects were randomly assigned to either the 1200 calorie low or high GI diet for 4 weeks. Subjects were then switched to the diet not followed initially for an additional 4 weeks. Both diets were equivalent in carbohydrate (43%), fat (38%) , protein (19 %), and fiber (17g). Each subject served as her own control for three blood drawings. Fasting glucose, insulin, c-peptide, fructosamine and a coronary risk profile were obtained. Glucose and insulin responses over two hours to a 35 g load were also measured. Weight loss achieved various outcomes significantly (p L 0. 01) decreasing both waist-to-hip ratio (WHR) and body mass index (BMI) (pLO.Ol) over the first 4 week period in all subjects. Changes in anthropometries over time continued in the group who switched from the HGI to the LGI significantly (pL 0 .01). Subjects who switched from the LGI to the HGI also continued to decrease in weight (p L 0. 05) and WHR (p L 0. 01) • Area Under the Curve (AUC) for insulin decreased for both groups significantly (p L0.05) at the end of the first 4 weeks. Subjects who switched from the HGI to the LGI did not decrease significantly in any carbohydrate metabolic parameter at end of week 8. Subjects who switched from the LGI to the HGI diet though, displayed decreases in glucose and insulin AUC significantly (pt.. 0. 05) yet fasting c-peptide increased significantly (pL 0.05). Both study groups ended the study with improved glucose responsiveness and a reduction in hyperinsulinemia. Total cholesterol and HDL cholesterol decreased significantly (pL 0.05) in the HGI group at the end of the first 4 weeks. When the LGI diet group was switched to the HGI diet for the last 4 weeks, total cholesterol and LDL-cholesterol decreased significantly (p L 0.001). Unfortunately, triglyceride levels increased in this group but not significantly. HDL- cholesterol concentrations also increased but not significantly . These findings suggest that a weight reducing diet and not the modification in carbohydrate con tent effected these metabolic parameters.