Proesmans 2003.

Methods	Randomised controlled cross‐over trial. Not blinded.
Participants	24 participants were eligible for the study, of these 9 were excluded from the analysis. Results from 15 participants (12 boys and 3 girls), median age was 8.7 years (range 3.5 ‐ 15.9 years).
Interventions	2 groups: 1. participants with less than 20 kg body weight were treated with 10 mg omeprazole daily; participants weighing more than 20 kg received 20 mg omeprazole daily; 2. no omeprazole.
Outcomes	Daily fat loss (g/day).
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Described as randomised, but no details of method given.
Allocation concealment (selection bias)	Unclear risk	Not discussed
Blinding (performance bias and detection bias) All outcomes	High risk	Not blinded (treatment versus nothing).
Incomplete outcome data (attrition bias) All outcomes	Low risk	24 participants were eligible for the study, of these 9 were excluded from the analysis (1 had viral illness during stool collection while taking omeprazole; in 8 participants residual fat loss could not be confirmed in stool collection when not taking omeprazole). Results from 15 participants.