Truth in nutrition

An article in New Food Economy this week warns that almost 40% of peer-reviewed dietary research is wrong, and that “we stop treating new nutrition studies like they contain the truth”. The online magazine argues that “Food research has some big problems: questionable data, untrustworthy results, and pervasive bias”.

In my book The Sugar Casino, I dedicated a chapter to nutrition and told the story of how two enterprising German journalists carried out a “scientific” study that “proved” that eating chocolate will help you to lose weight. They managed to get the study published in a scientific journal and sent out press releases to all the media. Within a week it was on the front page of all the newspapers. None of those newspapers verified the story or checked on how vigorous and exhaustive the study was; they based their stories entirely on the press release.

I wrote at the time,

 Nutrition is an inexact science. It is not possible to isolate the different elements or to establish the causality of any correlation. One test group may lose weight when they eat bananas, but that does not mean that they lose weight because they eat bananas. They could, because they were taking part in the study, have focused more than usual on their health and taken more exercise. Another point is that in the German study the test group that ate chocolate did lose more weight, but the sample size (4 people) was too small to be significant.”

As the New Food Economy wrote in their article, “it is not surprising if you are confused whether coffee causes cancer, or whether butter’s good for you or bad”.

Or whether sugar is a poison that should be regulated like nicotine, or just a calorie that can be part of a healthy diet. (A drunk at a cocktail party recently told me “sugar is toxic”. Sugar isn’t toxic, but alcohol is.)

Aeschylus, the founder of Greek tragedy, wrote “In war, truth is the first casualty.” Perhaps if he were alive today he would replace “war” with “nutrition”.

Julian Baggini touches on nutritional studies, and in particular on the sugar versus fat debate, in his book, A Short History of Truth: Consolations for a Post-Truth World.

He writes,

Hence in the early twenty-first century we find ourselves in a position where we know some truths are hidden by powerful groups to protect their own interests, we are not usually competent enough judges to know which claims about esoteric truths are correct, and we don’t have much confidence in experts to make those judgments for us.

When I read his book last year I found it flawed as I felt the author confused “truth” and “belief”. However I am now not so sure: what may be true for one individual may not be true for another. God may exist for some people, but not for others. Some people believe that the earth is flat or that NASA faked the moon landings.

And on a more mundane level, I may find that when I eat chocolate I lose weight—an individual truth—even though I screen out the fact that I at the same time I start to walk to and from work rather than take the bus. And I may not be able to be convinced otherwise. As Mr Baggini writes,

Reason works best in a blend, which includes not just logic but experience, evidence, judgment, subtlety of thought, and sensibility to ambiguity.

He adds,

“Despite the fact that intelligent people evidently disagree, we are inclined to think that what we believe really is rational and that those who disagree are being blinded by prejudices, ignorance or plain stupidity.”

Perhaps, rather sadly, he is right when he writes,

The relativist argues that there are no bare facts only interpretations of facts, mediated through culture. Nothing is true, period; it is only true for certain people, in certain contexts, or in certain senses. Truth has become personalized, with the individual sovereign over their own interpretation of reality.

So what should we do; who should we believe? In The Sugar Casino I wrote,

There is an old joke about a man who went to see his doctor and asked him what he should do to live to one hundred years old. The doctor replied that he should give up sex, sugar and alcohol and only eat fibrous vegetables mixed with unsweetened porridge.

“If I do that,” asked the man, “will I live to be one hundred?”

“No”, replied the doctor, “but it will seem like it”.

Oscar Wilde once famously said, “Everything in moderation, including moderation.” My grandmother used to say, “A little bit of what you fancy does you good” – and that is my first rule of healthy eating. So eat healthily, enjoy your food and don’t beat yourself up over that occasional slice of cheesecake.