Low versus high carbohydrate diet in type 1 diabetes: A 12-week randomized open-label crossover study.

AIMS: To compare the effects of a low carbohydrate diet (LCD < 100 g carbohydrate/d) and a high carbohydrate diet (HCD > 250 g carbohydrate/d) on glycaemic control and cardiovascular risk factors in adults with type 1 diabetes. MATERIALS AND METHODS: In a randomized crossover study with two 12-week intervention arms separated by a 12-week washout, 14 participants using sensor-augmented insulin pumps were included. Individual meal plans meeting the carbohydrate criteria were made for each study participant. Actual carbohydrate intake was entered into the insulin pumps throughout the study. RESULTS: Ten participants completed the study. Daily carbohydrate intake during the two intervention periods was (mean ± standard deviation) 98 ± 11 g and 246 ± 34 g, respectively. Time spent in the range 3.9-10.0 mmol/L (primary outcome) did not differ between groups (LCD 68.6 ± 8.9% vs. HCD 65.3 ± 6.5%, P = 0.316). However, time spent <3.9 mmol/L was less (1.9 vs. 3.6%, P < 0.001) and glycaemic variability (assessed by coefficient of variation) was lower (32.7 vs. 37.5%, P = 0.013) during LCD. No events of severe hypoglycaemia were reported. Participants lost 2.0 ± 2.1 kg during LCD and gained 2.6 ± 1.8 kg during HCD (P = 0.001). No other cardiovascular risk factors, including fasting levels of lipids and inflammatory markers, were significantly affected. CONCLUSIONS: Compared with an intake of 250 g of carbohydrate per day, restriction of carbohydrate intake to 100 g per day in adults with type 1 diabetes reduced time spent in hypoglycaemia, glycaemic variability and weight with no effect on cardiovascular risk factors.

Short-term effects of a low carbohydrate diet on glycaemic variables and cardiovascular risk markers in patients with type 1 diabetes: A randomized open-label crossover trial.

The aim of the present study was to assess the effects of a high carbohydrate diet (HCD) vs a low carbohydrate diet (LCD) on glycaemic variables and cardiovascular risk markers in patients with type 1 diabetes. Ten patients (4 women, insulin pump-treated, median ± standard deviation [s.d.] age 48 ± 10 years, glycated haemoglobin [HbA1c] 53 ± 6 mmol/mol [7.0% ± 0.6%]) followed an isocaloric HCD (≥250 g/d) for 1 week and an isocaloric LCD (≤50 g/d) for 1 week in random order. After each week, we downloaded pump and sensor data and collected fasting blood and urine samples. Diet adherence was high (225 ± 30 vs 47 ± 10 g carbohydrates/d; P < .0001). Mean sensor glucose levels were similar in the two diets (7.3 ± 1.1 vs 7.4 ± 0.6 mmol/L; P = .99). The LCD resulted in more time with glucose values in the range of 3.9 to 10.0 mmol/L (83% ± 9% vs 72% ± 11%; P = .02), less time with values ≤3.9 mmol/L (3.3% ± 2.8% vs 8.0% ± 6.3%; P = .03), and less glucose variability (s.d. 1.9 ± 0.4 vs 2.6 ± 0.4 mmol/L; P = .02) than the HCD. Cardiovascular markers were unaffected, while fasting glucagon, ketone and free fatty acid levels were higher at end of the LCD week than the HCD week. In conclusion, the LCD resulted in more time in euglycaemia, less time in hypoglycaemia and less glucose variability than the HCD, without altering mean glucose levels.

Low-Carbohydrate Diet Impairs the Effect of Glucagon in the Treatment of Insulin-Induced Mild Hypoglycemia: A Randomized Crossover Study.

OBJECTIVE: This study compared the ability of glucagon to restore plasma glucose (PG) after mild hypoglycemia in patients with type 1 diabetes on an isocaloric high-carbohydrate diet (HCD) versus a low-carbohydrate diet (LCD). RESEARCH DESIGN AND METHODS: Ten patients with insulin pump-treated type 1 diabetes randomly completed 1 week of the HCD (≥250 g/day) and 1 week of the LCD (≤50 g/day). After each week, mild hypoglycemia was induced by a subcutaneous insulin bolus in the fasting state. When PG reached 3.9 mmol/L, 100 µg glucagon was given subcutaneously, followed by 500 µg glucagon 2 h later. RESULTS: Compared with the HCD, the LCD resulted in lower incremental rises in PG after the first (mean ± SEM: 1.3 ± 0.3 vs. 2.7 ± 0.4 mmol/L, P = 0.002) and second glucagon bolus (4.1 ± 0.2 vs. 5.6 ± 0.5 mmol/L, P = 0.002). No differences were observed between the diets regarding concentrations of insulin, glucagon, and triglycerides. CONCLUSIONS: The LCD reduces the treatment effect of glucagon on mild hypoglycemia. Carbohydrate intake should be considered when low-dose glucagon is used to correct hypoglycemia.