In the present study, 12 patients with non-insulin-dependent diabetes mellitus (NIDDM) consumed eucaloric, mixed food diets on three consecutive days. Diets provided 50% of the calories as carbohydrate, 35% as fat, and 15% as protein. The percent of carbohydrate fed as complex (starches) and simple (monoand disaccharides) varied among the 3 days. On day 1, the diet contained 80% of the carbohydrate as complex and 20% as simple (80/20); another contained 50% complex and 50% simple (50/50); and the final diet contained 20% of the carbohydrate as complex and 80% as simple (20/80). All simple carbohydrates represent naturally occurring sugars in fruits, vegetables, and dairy products. No refined sugars were added to any of the diets. The three experimental diets were randomly assigned using a 3 × 3 Latin square design.
Blood was obtained hourly from 0800 to 1700 h for day-long glucose and insulin concentrations, and 24-h urine collections were made for the measurement of urine glucose. Mean (± SEM) day-long glucose concentrations were significantly greater for the 80/20 diet (2245 ± 199 mg/dl · h, P < 0.05) than for either the 50/ 50 (2030 ± 157 mg/dl · h) or the 20/80 diets (2008 ± 160 mg/dl · h). No significant differences were noted between the 50/50 and the 20/80 diets. In contrast, day-long insulin concentrations were not significantly different with 401 ± 62, 370 ± 50, and 369 ± 60 μU/ ml · h on the 80/20, 50/50, and 20/80 diets, respectively. Twenty-four-hour urinary glucose excretion paralleled plasma glucose concentrations. Significant differences were noted when the 80/20 diet (25.1 ± 4.5 g/ 24 h, P < 0.05) was compared with the 20/80 diet (9.7 ± 3.3 g/24 h). Substantial quantitative differences also existed between the 80/20 and 50/50 (12.2 ± 4.5 g7sol;24 h), but these differences did not reach statistical significance.
The results of the present study support the hypothesis that variations in relative proportions of naturally occurring, complex and simple dietary carbohydrate will have no deleterious effect on glycemia in patients with NIDDM. Thus, there seems to be no apparent reason why patients with NIDDM should avoid foods that are high in naturally occurring, simple carbohydrate.