Post-hoc analysis finds both continuous and intermittent calorie restriction reduce weight in type 2 diabetes.

BACKGROUND & AIMS: Various dietary approaches, such as continuous calorie-restricted (CCR) diets and, more recent, intermittent calorie-restricted (ICR) diets have demonstrated success in weight management and glycaemic control in people with type 2 diabetes. However, there are concerns about disproportionate decrease in fat-free mass (FFM) and consequently in resting energy expenditure (REE), with inconsistent results to date. Therefore, the aim of the present study was to evaluate the effects of a 3-month CCR diet and ICR diet on body composition and REE in people with type 2 diabetes and overweight or obesity. METHODS: In this post-hoc analysis of two ongoing trials (E-DIET and TIMED) in the Netherlands, we included people with type 2 diabetes and overweight or obesity that underwent a 3-month CCR diet (750 kcal per day) or ICR diet (eating window between 8AM and 6PM and 1300-1500 kcal per day). We measured differences in body composition, REE and glycaemic control over time within and (exploratively) between the groups. RESULTS: Sixty-seven participants (mean age 60 years; 56 % female; CCR: n = 41; ICR: n = 26) were included in the study. After three months, both interventions resulted in significant improvements in body composition, with a decrease in weight (CCR: 102.8 ± 17.1 kg to 97.7 ± 16.3 kg, p < 0.001; ICR: 107.3 ± 17.5 kg to 100.5 ± 15.2 kg, p < 0.001) and fat mass (CCR: 39.7 ± 7.7 % to 36.2 ± 7.8 %, p < 0.001; ICR: 38.5 ± 9.0 % to 35.8 ± 8.6 %, p < 0.001) while FFM increased (CCR: 59.6 ± 8.1 % to 64.9 ± 9.9 %, p = 0.001; ICR: 61.5 ± 9.1 % to 64.1 ± 8.7 %, p = 0.002). REE decreased significantly only in the CCR group (2006 ± 377 kcal to 1820 ± 348 kcal, p < 0.001). HbA1c decreased significantly from 61.0 [52.0-74.0] mmol/mol to 54.0 [43.0-66.0] mmol/mol, p = 0.028) in the CCR group, whereas a significant reduction in diabetes medication use (Medication Effect Score, MES) was seen in both groups (CCR: 2.41 [1.11-3.25] to 1.62 [0.62-2.36], p = 0.007; ICR: 0.38 [0.0-1.35] to 0.25 [0.0-0.67], p = 0.036), indicating improved diabetes control in both groups. No significant differences were observed between the two groups in all parameters except for dropout rate, which was 19 % for CCR and 0 % for ICR (p = 0.016). CONCLUSIONS: Both CCR and ICR improved body composition after three months in individuals with type 2 diabetes and overweight or obesity, without excessive fat-free mass loss. While direct comparison is limited by the post-hoc design, both diets appear promising, with a lower dropout rate in ICR suggesting greater feasibility. Further research should assess long-term effects and underlying mechanisms.