Olejko 1984.

Methods	Randomised controlled trial. Duration 6 weeks.
Participants	Adults (n = 24, 12 women and 12 men, mean (SD) age 22.8 years (6.1) awaiting elective orthognathic surgery. 12 of 24 patients had a weight below IBW at study inclusion. 100% follow up.
Interventions	Dietary instruction given verbally and in writing versus dietary instruction and an oral nutritional supplement (1.5 kcal/ml) to provide 50% of energy requirements (n = 16 )versus dietary instruction, an oral nutritional supplement to provide 50% of energy requirements and a nutritional supplement to take preoperatively (n = 8).
Outcomes	Survival*, body weight*, MUAC*, MAMC*, TSF*, serum chemistry and creatinine height index, macro and micronutrient intake.
Notes	No additional data available for this study.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Described as randomised, method not stated.
Allocation concealment (selection bias)	Unclear risk	Method not stated.
Blinding (performance bias and detection bias) Clinical outcomes	Unclear risk	Not stated.
Blinding (performance bias and detection bias) Functional outcomes	Unclear risk	Not stated.
Blinding (performance bias and detection bias) Nutritional outcomes	Unclear risk	Not stated.
Incomplete outcome data (attrition bias) All outcomes	Low risk	100% follow up.
Selective reporting (reporting bias)	High risk	All outcomes reported, but using general statements about change rather than numerical presentation e.g. 'the pre‐load group reported an average weight gain of 3.1% during the one month pre‐operative period, which was significantly greater (P < 0.05) than that of the other two groups'. No data are available from the authors therefore unclear risk of bias due to partial reporting.
Other bias	High risk	Baseline variables not given, not sure if groups similar at baseline.