Abstract
The aim of this study was to examine the mechanisms by which dietary carbohydrate and fat modulate fasting glycemia. We compared the effects of an eucaloric high-carbohydrate (89% carbohydrate) and high-fat (89% fat) diet on fasting glucose metabolism and insulin sensitivity in seven obese patients with type 2 diabetes using stable isotopes and euglycemic hyperinsulinemic clamps. At basal insulin levels glucose concentrations were 148 +/- 11 and 123 +/- 11 mg/dl (8.2 +/- 0.6 and 6.8 +/- 0.6 mmol/liter) on the high-carbohydrate and high-fat diet, respectively (P <0.001), with insulin concentrations of 12 &PLUSMN; 2 and 10 &PLUSMN; 1 μIU/ml (82 &PLUSMN; 11 and 66 &PLUSMN; 10 pmol/liter) (P = 0.08). Glucose production was higher on the high-carbohydrate diet (1.88 &PLUSMN; 0.06 vs. 1.55 &PLUSMN; 0.05 mg/kg.min (10.44 &PLUSMN; 0.33 vs. 8.61 &PLUSMN; 0.28 μmol/kg.min) (P <0.001) because of higher glycogenolysis. Gluconeogenic rates were not different between the diets. During the use of hyperinsulinemic euglycemic clamps, insulin-mediated suppression of glucose production and stimulation of glucose disposal were not different between the diets. Free fatty concentrations were suppressed by 89 and 62% (P <0.0001) on the high-carbohydrate and high-fat diet, respectively. We conclude that short-term variations in dietary carbohydrate to fat ratios affect basal glucose metabolism in people with type 2 diabetes merely through modulation of the rate of glycogenolysis, without affecting insulin sensitivity of glucose metabolism
Original language | English |
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Pages (from-to) | 6193-6197 |
Journal | Journal of clinical endocrinology and metabolism |
Volume | 89 |
Issue number | 12 |
DOIs | |
Publication status | Published - 2004 |