The WHO has issued draft recommendations that advise less consumption of saturated fats and trans fats. “Dietary saturated fatty acids and trans-fatty acids are of particular concern because high levels of intake are correlated with increased risk of cardiovascular diseases,” Dr. Francesco Branca, Director of WHO’s Department of Nutrition for Health and Development, told reporters. The dietary recommendations are based on scientific evidence developed in the last 15 years, he added.

These recommendations are another example of medical advice getting ahead of real data. If you advise a dietary change that will reduce the burden of cardiovascular disease, there should be good scientific evidence that such is the case. In other words, there should be controlled studies – age, sex, morbidity, etc matched – that show that those who eat the “beneficial” diet have a reduced incidence of CV disease. There are no such studies and there likely never will be as they would take years to complete and would also require a very large sample size.

What the WHO is doing is making an inference from changes in lipid metabolism that result from eating a diet containing less saturated and trans fats. They assume that if cholesterol levels go down and the ratio of high density lipoprotein to low density lipoproteins go up that the incidence of CV disease will fall. Such may be the case. But they leave the inference step out and move directly to a claim of benefit based on “scientific evidence” which doesn’t exist.

If they were straight forward about the basis for their advice they likely would get little press coverage and the public would pay even less attention to such advice. Another question not addressed by the WHO, assuming there is a CV benefit from adopting the diet advised by the WHO, is how big is this beneficial effect? Given the myriad of factors that contribute to the onset of CV disease it’s very likely that that the benefit of this dietary change, if it exists at all, is very small. A beneficial effect of the diet recommended by the WHO could be statistically significant but of such a small magnitude as to be clinically insignificant.

So what’s a concerned eater to do? As always, use a little common sense. Don’t eat a lot more than your need to maintain health, get a little exercise, control your blood pressure if it’s high, hope you have the right parents,and enjoy life as best you can for as long as you can.