The effect of intermittent compared with continuous energy restriction on glycaemic control in patients with type 2 diabetes: 24-month follow-up of a randomised noninferiority trial

Aims: We investigated the effects of intermittent compared to continuous energy restriction on glycaemic control in patients with type 2 diabetes mellitus. 

Methods: Adults (N = 137) with type 2 diabetes (mean [SD] HbA1c level, 7.3% (56 mmol/mol) [1.3%] [14.2 mmol/mol]) were randomised to one of two diets for 12 months. The intermittent group (n = 70) followed a 2100–2500 kJ (500–600 kcal) diet 2 non-consecutive days/week and their usual diet for 5 days/week. The continuous group (n = 67) followed a 5000–6300 kJ (1200–1500 kcal) diet for 7 days/week. Follow-up occurred at 24 months, 12 months after the completed intervention. The primary outcome was change in HbA1c and the secondary outcome was weight loss. 

Results: Intention-to-treat analysis showed an increase in mean [SEM] HbA1c level at 24 months in both the continuous and intermittent groups (0.4% [0.3%] vs 0.1% [0.2%] respectively; P = 0.32) (4.4 [3.3 mmol/mol] vs 1.1 [2.2 mmol/mol]; P = 0.32), with a between-group difference of 0.3% (90% CI, −0.31 to 0.83%) (3.3 mmol/mol [90% CI, −3.2 to 9.1 mmol/mol]) outside the prespecified boundary of ± 0.5% (5.5 mmol/mol), so statistical equivalence was not shown. Weight loss was maintained (P < 0.001) at −3.9 kg [1.1 kg] in both groups at 24 months, with a between-group difference of 0.07 kg (90% CI, −2.5 to 2.6 kg) outside the prespecified boundary of ±2.5 kg. There were no significant differences between groups in body composition, fasting glucose levels, lipid levels, or total medication effect score at 24 months, which remained less than baseline. 

Conclusions: In this prospective analysis weight loss was maintained but despite this HbA1c increased to above baseline levels in both groups.