A randomised trial of the feasibility of a low carbohydrate diet vs standard carbohydrate counting in adults with type 1 diabetes taking body weight into account.

BACKGROUND AND OBJECTIVES: To determine the effect of a low carbohydrate diet and standard carbohydrate counting on glycaemic control, glucose excursions and daily insulin use compared with standard carbohydrate counting in participants with type 1 diabetes. METHODS AND STUDY DESIGN: Participants (n=10) with type 1 diabetes using a basal; bolus insulin regimen, who attended a secondary care clinic, were randomly allocated (1:1) to either a standard carbohydrate counting course or the same course with added information on following a carbohydrate restricted diet (75 g per day). Participants attended visits at baseline and 12 weeks for measurements of weight, height, blood pressure, HbA1c, lipid profile and creatinine. They also completed a 3-day food diary and had 3 days of continuous subcutaneous glucose monitoring. RESULTS: The carbohydrate restricted group had significant reductions in HbA1c (63 to 55 mmol/mol (8.9-8.2%), p<0.05) and daily insulin use (64.4 to 44.2 units/day, p<0.05) and non-significant reductions in body weight (83.2 to 78.0 kg). There were no changes in blood pressure, creatinine or lipid profile and all outcomes in the carbohydrate counting group were unchanged. There was no change in glycaemic variability as measured by the mean amplitude of glycaemic excursion in either group. CONCLUSIONS: A low carbohydrate diet is a feasible option for people with type 1 diabetes, and may be of benefit in reducing insulin doses and improving glycaemic control, particularly for those wishing to lose weight.

From 'pleasure to chemistry': the experience of carbohydrate counting with and without carbohydrate restriction for people with Type 1 diabetes.

INTRODUCTION: Matching carbohydrate intake with insulin dosage is recommended management for people with Type 1 diabetes. However, international interest in restricted carbohydrate diets is growing. General practitioners and practice nurses need to know how to advise people with Type 1 diabetes regarding low-carbohydrate diets. This study aimed to explore the carbohydrate counting experiences of people with Type 1 diabetes in a trial with and without a diet restricted to 75 g of carbohydrate per day. METHODS: Eight participants were interviewed by focus group or interview 12 weeks after a carbohydrate counting course with individual dietary choice or the same course with information on restricted carbohydrate eating and a daily maximum intake of 75 g of carbohydrate. Data were analysed using a qualitative thematic analysis approach. FINDINGS: Themes included the need for insulin management skills, impact of the dietary experience, and need for dietary knowledge. The restricted-carbohydrate group encountered mealtime insulin resistance and difficulty managing insulin dosages when transitioning on and off the low-carbohydrate diet. The diet impacted on mood, feelings of satiety and it was reported that food changed from being 'a pleasure to chemistry'. Both groups described feeling empowered to manage their diabetes as a result of the carbohydrate counting course. CONCLUSION: Participants reported increased knowledge and challenging insulin management. The restricted-carbohydrate group reported mealtime insulin resistance and a strong dietary impact. Extra health professional support may be required, especially at dietary transition periods. More research is warranted into the reported mealtime insulin resistance.