Although low-fat high-
carbohydrate diets are recommended for patients with
non-insulin-dependent diabetes mellitus (
NIDDM) in an effort to reduce the risk of
coronary artery disease (CAD), the results of short-term studies have shown that these diets can lead to changes in
carbohydrate and lipid metabolism associated with an increased risk of CAD. This study has extended these earlier observations by determining the metabolic effects of such diets over a longer period in these patients. The comparison diets contained either 40 or 60% of the total calories as
carbohydrates, with reciprocal changes in fat content from 40 to 20% consumed in random order for 6 wk in a crossover experimental design. The ratio of polyunsaturated to saturated fat and the total
cholesterol intake were held constant in the two diets. Plasma
glucose and
insulin concentrations were significantly (P less than .001) elevated throughout the day when patients consumed the 60%
carbohydrate diet, and 24-h urinary
glucose excretion more than doubled (0.8 vs. 1.8 mol/24 h). Fasting plasma total and
very-low-density lipoprotein (
VLDL) triglyceride (TG) concentrations increased by 30% (P less than .001) after 1 wk on the 60%
carbohydrate diet, and the magnitude of
carbohydrate-induced
hypertriglyceridemia persisted unchanged throughout the 6-wk study period. Total plasma
cholesterol concentrations were similar after both diets. However,
VLDL cholesterol (VLDL-chol) was significantly increased, whereas both
low-density lipoprotein (
LDL-) and
high-density lipoprotein (HDL-) chol concentrations were significantly decreased after consumption of the 60%
carbohydrate diet. Consequently, neither total-chol-to-HDL-chol nor
LDL-chol-to-HDL-chol ratios changed.(ABSTRACT TRUNCATED AT 250 WORDS)