The effect of intermittent energy restriction on weight loss and diabetes risk markers in women with a history of gestational diabetes: a 12-month randomized control trial.

BACKGROUND: Weight loss after gestational diabetes (GDM) can prevent or delay the onset of type 2 diabetes. Intermittent energy restriction (IER) may offer an alternative to continuous energy restriction (CER) for weight loss. OBJECTIVES: We compared the effects of IER (2 days per week) to daily CER over 12 mo on weight loss and diabetes risk markers in overweight women with previous GDM. METHODS: Overweight females (n = 121) ≥18 y were randomized 1:1 to either IER [2-d 500 kcal (2100 kJ); n = 61] or CER [1500 kcal (6000 kJ); n = 60] in this 12-mo noninferiority trial. RESULTS: The trial was completed by 62 participants with a median age of 39.6 y [Quartile (Q) 1 to Quartile 3, 34.9 to 43.9 y] with a median BMI of 32.6 kg/m2 (Q1 to Q3, 28.5 to 37.9 kg/m2) at a median of 2.9 y after GDM (Q1 to Q3, 2.1 to 6.4 y; 49% attrition; IER n = 29; CER n = 30; P = 0.8). The mean ± SD weight loss was significant over time (P < 0.001) but not by diet group (IER -4.8 ± 5.0 kg; CER -3.2 ± 5.0; P = 0.2). The mean between-group difference was -1.6 kg (95% CI: -4.2 to 1.0 kg; P = 0.2). There were no significant between-group differences in change in HbA1c, fasting plasma glucose, fasting serum insulin, HOMA-IR or 2-h oral glucose tolerance at 12 mo (p>0.05). The trial was registered at https://www.anzctr.org.au/ (ACTRN12617001476325). CONCLUSIONS: IER produces comparable weight loss to CER over 12 mo in overweight women with previous GDM. The high dropout rate in this study is a limitation in the interpretation of these results. Larger studies are needed to confirm noninferiority of IER compared to CER.