Background We previously showed in a randomised crossover trial that a moderate carbohydrate diet improved mean glucose and time in range (TIR) in adults with type 1 diabetes without adverse effects. This study aimed to examine diet quality and explore baseline predictors of improved glycaemic control and treatment satisfaction. Methods Secondary analysis of a randomised crossover trial including adults with type 1 diabetes and glycated haemoglobin A1c (HbA1c) ≥58 mmol/mol who followed a moderate carbohydrate diet (30% energy from carbohydrates) and a traditional diet (50% energy from carbohydrates) for 4 weeks each, separated by a 4-week washout period. Glucose levels, diet and treatment satisfaction were assessed using masked continuous glucose monitoring (CGM), 4-day food records and the Diabetes Treatment Satisfaction Questionnaire (DTSQs), respectively. Correlation analyses between baseline variables (dietary intake, HbA1c, age, sex, physical activity and insulin delivery route) and changes in CGM metrics such as mean glucose, TIR, time above range, time in tight range and DTSQs score between diets were performed. Results This post hoc analysis included 50 individuals with a mean (SD) baseline HbA1c of 69 (11) mmol/mol, body mass index 29 (5) kg/m 2 , age 48 (14) years and 25 (50%) were female. Carbohydrate quality was similar across the two diets, whereas fat quality differed, with a higher proportion of unsaturated fat and higher cholesterol intake in the moderate carbohydrate diet. Fibre and saturated fat intakes did not fully meet general recommendations in either diet. Age 40–60 years was significantly associated with greater improvements in TIR (p=0.045). Lower baseline carbohydrate intake (p=0.039) and improved mean glucose during the moderate carbohydrate diet (p=0.034) were associated with higher treatment satisfaction. Conclusions Fibre and saturated fat intakes were similar between diets, but neither fully aligned with recommendations, highlighting the need to ensure adequate fibre intake and appropriate levels of saturated fat when recommending a moderate carbohydrate diet. Middle-aged adults appeared to benefit most from a moderate carbohydrate diet in terms of glucose control. Trial registration number NCT03400618 .
Isaksson et al. (Wed,) studied this question.