Mild Caloric Restriction Decreases Insulin Requirements in Patients With Type 2 Diabetes and Severe Insulin Resistance

Abstract

Type 2 diabetes (T2D) affects ~10% of the US population, a subset of whom have severe insulin resistance (SIR) (>200 units/d). Treatment of these patients with high-dose insulin presents logistical and compliance challenges. We hypothesized that mild caloric restriction would reduce insulin requirements in patients with T2D and SIR.This was a retrospective study at the National Institutes of Health Clinical Center. Inclusion criteria were as follows: T2D, and insulin dose >200 units/d or >2 units/kg/d. The intervention consisted of mild caloric restriction during a 3 to 6-day hospitalization. The major outcomes were change in insulin dose and blood glucose from admission to discharge.Ten patients met inclusion criteria. Baseline glycated hemoglobin A1c was 10.0 ± 1.6% and body mass index 38.8 ± 9.0 kg/m. Food intake was restricted from 2210 ± 371 kcal/d preadmission to 1810 ± 202 during the hospital stay (16.5% reduction). Insulin dose decreased from 486 ± 291 units/d preadmission to 223 ± 127 at discharge (44% reduction, P = 0.0025). Blood sugars decreased nonsignificantly in the fasting state (from 184 ± 85 to 141 ± 42, P = 0.20), before lunch (239 ± 68 to 180 ± 76, P = 0.057), and at bedtime (212 ± 95 to 176 ± 48, P = 0.19), and significantly decreased before dinner (222 ± 92 to 162 ± 70, P = 0.016).Mild caloric restriction, an accessible and affordable intervention, substantially reduced insulin doses in patients with T2D and SIR. Further studies are needed to determine if the intervention and results are sustainable outside of a hospital setting.

FIGURE 1

(A) Insulin requirements before admission and after 3 to 6 days of mild caloric restriction in 10 patients with type 2 diabetes and severe insulin resistance. (B) Insulin requirements on each day of the hospitalization in the same patients (solid black lines/circles represent individual patients, dashed line/squares show the mean for all patients).

FIGURE 2

Mean (SD) capillary blood glucose in the first 24 hours after admission (black bars) versus after 3 to 6 days of mild caloric restriction (white bars) in 10 patients with type 2 diabetes and severe insulin resistance in the fasting state, prelunch, predinner, and at bedtime.

FIGURE 3

Mean (SD) capillary blood glucose on each day of the hospitalization during 3 to 6 days of mild caloric restriction in 10 patients with type 2 diabetes and severe insulin resistance in the fasting state (A), prelunch (B), predinner (C), and at bedtime (D).