Government advice may be a fat lot of good. A controversial study claims dietary guidelines issued on fat intake to reduce the risk of heart disease were not supported by evidence from clinical trials.
In 1977, the US government said fat intake should make up no more than 30% of an individual’s diet, and saturated fats should be limited to 10% of total energy intake. The same guidelines were issued in the UK in 1983.
Zoe Harcombe and colleagues, at the University of of the West of Scotland (UK), studied the only seven relevant trials they could find from before 1983. They found no evidence to support the advice.
However, the study has been criticised for looking solely at the trials. The guidelines may still have been based on good scientific evidence, says Christine Williams, at the University of Reading (UK). They are usually developed using a range of evidence, not just trials.
Harcombe, Z., Baker, J.S., Cooper, S.M., Davies, B., Sculthorpe, N., DiNicolantonio, J.J. & Grace, F. (2015) Evidence from Randomised Controlled Trials did not Support the Introduction of Dietary Fat Guidelines in 1977 and 1983: A Systematic Review and Meta-analysis. Open Heart. 2(1). doi:10.1136/openhrt-2014-000196.