Low-carbohydrate diet proved effective and safe for youths with type 1 diabetes: A randomised trial

Aim: Low-carbohydrate (LC) diets have gained popularity. We compared glycaemic and metabolic parameters following an LC versus a Mediterranean (MED) diet in adolescents and youths with type 1 diabetes. Methods: In a six-month, open-label, randomised trial, 40 individuals were assigned to either diet. Glycaemic outcomes, based on continuous glucose monitoring, included per cent time of blood glucose in the range [3.9–10.0 mmol/L (70–180 mg/dL)] and haemoglobin A1c (HbA1c). Results: Twenty-eight (70%) were females. The median age was 18 years. After 6 months, the median time in range increased from 47% to 58% in the LC and from 52% to 64% in the MED diet group (p = 0.98). The delta values for the time in range were 16% and 7% for the respective groups (p = 0.09). The percentage of time >13.9 mmol/L (>250 mg/dL) improved more in the LC diet than in the MED diet group: −10% vs. −2% (p = 0.005). The percentage of time <3.0 mmol/L (<54 mg/dL) was comparable. The delta HbA1c improved in both groups: −0.7% vs. −0.1% (p = 0.02). Changes in BMI Z-score and lipid levels were similar. Conclusion: Both diets improved glycaemic outcomes in adolescents and youths with type 1 diabetes, without increasing hypoglycaemia or cardiovascular risk factors, indicating comparable safety and efficacy.