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

Abstract

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

“…Diet plans were followed in terms of carbohydrate quantity as documented by insulin pump downloads; however, we did not assess whether total energy goals were met during the intervention periods. Weight loss following the implementation of a low carbohydrate diet strategy in people with type 1 diabetes and type 2 diabetes has previously been reported and may be related to a greater satiating effect of fat and protein; however, the underlying mechanisms remain to be elucidated …”

“…Based on this reasoning, some people with type 1 diabetes practise low carbohydrate diets and there have been personal and observational reports of positive outcomes . However, to date scientific evidence from randomized trials in type 1 diabetes is sparse …”

Prevalence of underweight, overweight, and obesity in children and adolescents with type 1 diabetes: Data from the international SWEET registry

“…Several factors, which are common in adolescents with or without T1D, such as sedentary behavior, reduced exercise (especially in females), and unhealthy eating habits, may contribute to favor a positive energy balance . Other factors favoring body fat accumulation are specific to diabetes, including extra calorie intake to prevent or correct hypoglycemia, the consumption of low carbohydrate high fat foods, to reduce postprandial glucose increase, and the chronic exposure of the peripheral tissues to non‐physiologic hyperinsulinemia due to the subcutaneous insulin injections or infusion via insulin pump . Nutritional strategies to reduce nocturnal hypoglycemia, if insulin pump or long‐acting analog insulin (such as glargine or degludec insulin) are not used, include the ingestion of a bedtime snack containing carbohydrates and protein, although the American Diabetes Association (ADA) and the Endocrine Society reported the absence of consensus on this practice .…”

“…Nutritional strategies to reduce nocturnal hypoglycemia, if insulin pump or long‐acting analog insulin (such as glargine or degludec insulin) are not used, include the ingestion of a bedtime snack containing carbohydrates and protein, although the American Diabetes Association (ADA) and the Endocrine Society reported the absence of consensus on this practice . Moreover, nocturnal hypoglycemia in people without diabetes stimulates spontaneous food intake the following morning, with special preference for carbohydrates . Similar mechanisms may contribute to the frequently observed body weight gain in insulin‐treated patients.…”

Effect of low‐carbohydrate diet on markers of renal function in patients with type 2 diabetes: A meta‐analysis

“…Arterial stiffness increased with provision of ketogenic diet for 2 years, which may contribute to the development of cardiovascular diseases . Declaring dietary carbohydrate restriction as a recommended healthy diet, as was done previously by Dr Atkins in his dietary guideline, should wait until all safety considerations have been met. This caveat should be performed despite the fact that more and more evidence continues to show advantage of LCD on metabolism …”