Wanted: evidence that a bad diet causes 70,000 premature deaths every year

"Poor diets are causing 70,000 premature deaths every year."—BBC News, 13 July 2015

The British Medical Association's (BMA) public cry for a 20% tax on sugary drinks to be introduced in an attempt to tackle obesity in the UK is covered in numerous reports today. All claim that a bad diet is responsible for 70,000 premature deaths every year.

Although this figure featured in a recent BMA report published this month, we tracked the original source back to old Department of Health data featured in a 2006 Ofcom report.

The 70,000 figure is the sum of the estimated number of deaths that could be avoided if the public reduced the salt, saturated fat and sugar in their diet, as well as increasing their fruit and vegetable intake to meet nutritional guidelines.

But further assumptions are unclear—would these avoidable deaths take immediate effect if these dietary changes were made? And would someone be counted twice if they made more than one improvement to their diet in the areas covered by the research?

We can't be sure that the 2006 analysis is still relevant today and it's unclear how these old figures were arrived at, so for now there's no good reason to rely upon the 70,000 figure. Food consumption may not be the same now as it was a decade ago; either through lifestyle choices or as a result of changes to food industry standards such as those implemented through targets set by the Coalition government.

We contacted the Department of Health, who were unaware of their association with this 70,000 figure, so as it stands we're left in the dark about how this widely quoted figure has been worked out.

If you worked on this analysis or have more information then get in touch with us at team@fullfact.org.