National dietary guidelines were introduced in 1977 and 1983, by the US and UK governments, respectively, with the ambition of reducing coronary heart disease (CHD) by reducing fat intake. To date, no analysis of the evidence base for these recommendations has been undertaken. The present study examines the evidence from randomised controlled trials (RCTs) available to the US and UK regulatory committees at their respective points of implementation.

Harcombe et al have conducted a systematic review and meta-analysis of randomised controlled trials (RCTs) that would have been available to the regulatory committees in the USA and the UK when guidelines on dietary fat intake were introduced (in 1977 and 1983, respectively). They found no evidence from RCTs to support the introduction of these guidelines, which leads the authors to question whether they should ever have been introduced in the first place. (Editorial)