The effects of carbohydrate variation in isocaloric diets on glycogenolysis and gluconeogenesis in healthy men

• Published in: The journal of clinical endocrinology and metabolism 2000-05, Vol.85 (5), p.1963-1967
• Main Authors: BISSCHOP, P. H, PEREIRA ARIAS, A. M, ACKERMANS, M. T, ENDERT, E, PIJL, H, KUIPERS, F, MEIJER, A. J, SAUERWEIN, H. P, ROMIJN, J. A
• Format: Article
• Language: English
• Subjects: Adult; Biological and medical sciences; Blood Glucose - metabolism; C-Peptide - blood; Deuterium; Dietary Carbohydrates; Energy Intake; Epinephrine - blood; Feeding. Feeding behavior; Fundamental and applied biological sciences. Psychology; Glucagon - blood; Gluconeogenesis; Glucose - administration & dosage; Glucose - metabolism; Glycogen - metabolism; Hormones - blood; Humans; Hydrocortisone - blood; Infusions, Intravenous; Insulin - blood; Male; Middle Aged; Norepinephrine - blood; Reference Values; Vertebrates: anatomy and physiology, studies on body, several organs or systems
• ISSN: 0021-972X; 1945-7197
• DOI: 10.1210/jc.85.5.1963

To evaluate the effect of dietary carbohydrate content on postabsorptive glucose metabolism, we quantified gluconeogenesis and glycogenolysis after 11 days of high carbohydrate (85% carbohydrate), control (44% carbohydrate), and very low carbohydrate (2% carbohydrate) diets in six healthy men. Diets were eucaloric and provided 15% of energy as protein. Postabsorptive glucose production was measured by infusion of [6,6-2H2]glucose, and fractional gluconeogenesis was measured by ingestion of 2H2O. Postabsorptive glucose production rates were 13.0 +/- 0.7, 11.4 +/- 0.4, and 9.7 +/- 0.4 micromol/kg x min after high carbohydrate, control, and very low carbohydrate diets, respectively (P < 0.001 among the three diets). Gluconeogenesis was about 14% higher after the very low carbohydrate diet (6.3 +/- 0.2 micromol/kg x min; P = 0.001) compared to the control diet, but was not different between the high carbohydrate and control diets (5.5 +/- 0.3 vs. 5.5 +/- 0.2 micromol/kg x min). The rates of glycogenolysis were 7.5 +/- 0.5, 5.9 +/- 0.3, and 3.4 +/- 0.3 micromol/kg x min, respectively (P < 0.001 among the three diets). We conclude that under eucaloric conditions in healthy subjects, dietary carbohydrate content affects the rate of postabsorptive glucose production mainly by modulation of glycogenolysis. In contrast, dietary carbohydrate content affects the postabsorptive rate of gluconeogenesis minimally, as evidenced by only a slight increase in gluconeogenesis during severe carbohydrate restriction.