Methods	Quasi-randomised controlled trial, set in antenatal clinic at Wollongong Hospital, Wollongong, NSW, Australia
Participants	Inclusion criteria: healthy, pregnant women from the antenatal clinic at Wollongong Hospital and from 2 obstetricians in private practice. They were aged 21- 40 years, had a singleton pregnancy, were between 12 and 16 weeks’ gestation, were nonsmokers, and consumed no more than 1 alcoholic drink each day Exclusion criteria: any problem associated with glucose metabolism or insulin resistance or that interfered with the ability of the study participant to follow dietary instructions
Interventions	Participants were randomised to a low glycaemic diet or high glycaemic diet Low glycaemic diet (n = 32): seen by dietitian 5 times during pregnancy, received dietary recommendation for low GI diet with 33% fat, 55% CHO. The low GI diet was based on verified low-GI foods, including pasta and brand-name breads and breakfast cereals with a high fibre content High glycaemic diet (n = 30): also seen by dietitian 5 times during pregnancy, received dietary recommendation for moderate-to-high GI diet (high fibre, low sugar) with 33% fat, 55% CHO
Outcomes	Weight gain (from 12 weeks to 36 weeks), large-for-gestational age (>90th centile for birthweight), small-for-gestational age (< 10th centile for birthweight)
Notes	Age (low GI, high GI): 30.1 ± 0.7, 29.6 ± 0.7. BMI at baseline (low GI, high GI): 24.4 ± 0.7, 26.6 ± 0.9 kg/m2 The baseline visit was between 12-16 weeks’ gestation.
Risk of bias
Bias	Authors’ judgement	Support for judgement
Random sequence generation (selection bias)	High risk	Alternation.
Allocation concealment (selection bias)	High risk	Alternate allocation to study groups.
Blinding (performance bias and detection bias) All outcomes	Unclear risk	No information provided.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Loss of participants to follow-up: In the low-GI diet group, 2 women withdrew due to being unwilling to follow the diet and 1 delivered before the final visit. In high-GI diet group, 1 woman was unwilling to follow the diet, 1 lost to follow-up, and 3 miscarriages Intention-to-treat analysis: data were analysed for participants according to their randomly-allocated group, not all original participants were included in the analysis
Selective reporting (reporting bias)	Unclear risk	Could not determine.
Other bias	Low risk	Baseline characteristics were similar.