Testing the feasibility of an intermittent low-energy diet in women with gestational diabetes

The study aimed to assess feasibility, acceptability and safety of an ILED in a randomised controlled trial of ILED vs. best NHS care healthy diet and exercise advice in women with Gestational Diabetes Mellitus (GDM) with body mass index ≥27.5 kg/m² (≥25 kg/m² in high-risk minority ethnic groups) in the last trimester of pregnancy.

Participants were randomised (1:1) to receive an ILED (1000 kcal on two non-consecutive days of the week with 5 days/week of best NHS care healthy diet and exercise advice) or best NHS care healthy diet and exercise advice 7 days/week from recruitment (24-30 weeks gestation) until delivery (BNC). Primary outcomes were uptake, retention and adherence to the interventions. Maternal and neonatal safety outcomes were explored, and secondary outcomes assessed fidelity of the delivery of the intervention and completeness of study data across all trial participants.

Participants were randomised to ILED (n = 14) or BNC (n = 12) and 73% (n = 19; ILED n = 10, BNC n = 9) received their allocated intervention. There was low study retention (58%; ILED n = 7; BNC n = 8) and low adherence to the ILED median (IQR) 37% (8%-50%) out of prescribed days; however, the study achieved a feasible uptake rate (31%; n = 26). There were no adverse events specifically related to the ILED.

Our findings suggest that ILED may not be feasible in the third trimester in people with GDM. Future research should explore alternative interventions and interventions earlier in pregnancy for the prevention and management of GDM.

NCT05344066.