Effect of fat-free diet on insulin requirements in type I diabetes controlled with artificial β-cell

We investigated the effect of eliminating calories derived from fat sources on postprandial and basal insulin requirements in five patients with type I (insulin-dependent) diabetes mellitus. The patients were studied on a metabolic ward on two solid-food diets with similar quantities of carbohydrate and protein with or without the addition of fat. Diet A was isocaloric (weight maintenance) with calories distributed as 45% carbohydrate, 15% protein, and 40% fat. Diet B contained the same carbohydrate and protein content as diet A but was virtually fat free and therefore hypocaloric (1233 ± 106 vs. 1830 ± 99 cal, mean ± SE). The diets were given as five equal meals each day on consecutive days. Insulin requirements and blood glucose measurements were determined by use of the artificial β-cell. During the study, mean (± SE) preprandial blood glucose levels were maintained at 85 ± 11 mg/dl, and peak postprandial blood glucose levels were <180 mg/dl. The elimination of fat calories had no effect on total (68.9 ± 10.3 vs. 69.3 ± 4.9 U/day), postprandial (9.8 ± 3.8 vs. 10.3 ± 3.7 U/meal), or basal (1.9 ± 0.2 vs. 1.8 ± 0.2 U/h) insulin requirements. Thus, despite a hypocaloric diet, no change in insulin requirements was noted when fat-derived calories were deleted from the diet. We conclude that fat-derived calories do not alter short-term basal or postprandial insulin requirements in type I diabetes.