Effects of a low-carbohydrate diet in adults with type 1 diabetes: an interventional study protocol

Background: Type 1 diabetes (T1D) is an autoimmune condition characterised by pancreatic beta cell destruction and absolute insulin deficiency. The varying impact of dietary factors on blood glucose levels is well-known, yet there remains a lack of consensus surrounding the optimal dietary approaches to achieve glycaemic control in T1D. The aim of this research is to assess the efficacy of a low-carbohydrate (LC) diet in adults with T1D. We will set out to determine whether significant differences in T1D management outcomes exist between a LC diet and habitual diets higher in carbohydrate. Our primary hypothesis is that a LC diet will result in improved T1D management compared to habitual diets higher in carbohydrates. Methods: This is a 28-week single arm within-participant intervention study involving a 4-week control period, a 12-week intervention period and a 12-week follow-up. We plan to recruit 20 adults (18-60 years) with T1D (duration ≥6 months) who have suboptimal glycaemic control (HbA1c>7.0%). The primary outcome is haemoglobin A1c (HbA1c) and secondary outcomes include glycaemic variability, frequency of hypoglycaemia, total daily insulin, and quality of life. This LC diet will start at 50 g of digestible carbohydrate per day and then there will be opportunity to increase or decrease within a broader range of 25-75 g/day according to individual blood glucose levels and personal preference.  Participants will meet individually with the study dietitian for a total of six fortnightly sessions to receive dietary instruction, strategies, and education. Participants will continue to work with a member of their usual diabetes care team for specific advice regarding insulin management. Conclusions: Current dietary management strategies for T1D appear to be lacking in effect and additional dietary therapies, including LC diets, require urgent consideration. Therefore, an interventional study investigating a patient-led LC dietary approach will be of important clinical relevance for healthcare practitioners and may help to better inform clinical practice guidelines for T1D management. Trial Registration : https://www.anzctr.org.au/ACTRN12621000764831.aspx