It’s said that the fastest way to start an argument online is to post about politics. But talking about nutrition can’t be too far behind in what’s most likely to annoy, rankle and infuriate anyone who comes into contact with your comment, however innocent or innocuous you think it is.

Much like politics, and many other matters in the modern world, nutrition and, by extension supplementation, have become tribal topics, with specific approaches to eating now subject to a fierce and impassioned championing or evisceration by highly vocal minorities, who believe one dietary approach as not only nutritionally, but also morally, superior to all others.

One man who has seen countless nutritional trends, fads and crazes come and go over the years - remember raspberry ketones, anyone? - is Ian Marber, one of the most respected and established ...