Methods	RCT
Participants	Free living men who had participated in NDHS 1st studies (USA) CVD risk: low Control: randomised 304, analysed 280 Intervention BC: randomised 194, analysed 179 Mean years in trial: control 0.6, intervention BC 0.6 % male: 100 Age: unclear (all 45-54)
Interventions	Reduced and modified fat vs usual diet Control aims: total fat 40%E, SFA 16-18%E, dietary chol 650-750mg/d, P/S 0.4, X - advice to continue usual diet Intervention aims: BC total fat 30-40%E, SFA reduced, dietary chol 350-450mg/d, increased PUFA, P/S 1.5-2.0 Control methods: dietary advice to reduce saturated fat and cholesterol (plus 10 follow up visits with nutritionist), purchase of‘usual fat’ items from a trial shop Intervention BC methods: dietary advice to reduce saturated fat and cholesterol (plus 10 follow up visits with nutritionist), plus purchase of appropriately reduced and modified fat items from a trial shop Total fat intake (through study): BC 32.5 (sd unclear)%E, cont 35.5 (sd unclear)%E Saturated fat intake (through study): BC 7.4 (sd unclear)%E, cont 12.0 (sd unclear)%E Style: food provided Setting: community
Outcomes	Stated trial outcomes: lipid levels and dietary assessment Data available on total mortality? no Cardiovascular mortality? yes (no events) Events available for combined cardiovascular events: fatal and non-fatal MI, peripheral vascular events Secondary outcomes: cancer diagnoses (no events), total and non-fatal MI Tertiary outcomes: none
Notes
Risk of bias
Bias	Authors’ judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Stratified randomisation by the statistical centre
Allocation concealment (selection bias)	Low risk
Blinding (performance bias and detection bias) All outcomes	Low risk	Some participants continued with advice to reduce saturated fat and purchased blinded foods from a trial shop, but half of the participants were instructed in their own purchase of appropriate foods from normal shops to compile their own dietary regimen
Incomplete outcome data (attrition bias) All outcomes	High risk	Dropouts do not appear to have been followed for death or CV events. Deaths, cancer and CV events for participants otherwise still included in the study were collated as a reason for study exclusion
Selective reporting (reporting bias)	Low risk	Not relevant for primary and secondary outcomes as all trialists asked for data
Other bias	Low risk
Free of systematic difference in care?	Low risk	Trial shop used by both groups, plus dietary advice. See Control and Intervention Methods in Interventions section of the Table of Characteristics of Included Studies
Free of dietary differences other than fat?	Low risk	See Control and Intervention Aims in Interventions section of the Table of Characteristics of Included Studies