steakI always keep an eye on news about diet. After all it is one area of health that you can control—if you have good information. But the recent release of the U.S. government’s dietary guidelines really has brought home the fact that much of what we’ve been told by mainstream medical authorities for the last 50 years turns out to be wrong. Salt is no longer a silent killer; dietary cholesterol won’t cause you to keel over with a heart attack; saturated fat from red meat, cheese, and cream are OK as long as you’re not packing on pounds (although this is still disputed by the government guidelines in the face of substantial evidence vindicating saturated fat). The only things we need to be careful about is sugar, refined carbs, and processed meat. (This assumes of course that you don’t have a medical condition that requires dietary restrictions)

These new guidelines won’t cause me to change much in my diet. We eat very few salt-laced processed foods—I prefer to cook fresh foods from scratch most of the time so I have never restricted salt intake. I love vegetables and I don’t like eggs, and there are good environmental reasons not to eat too much meat, so I plan no changes there. Cream tends to dull flavors so I have always been light-handed with that anyway for reasons other than health. But cheese? This is a good excuse to spend more time in the cheese shop. Truth be told, I was never willing to sacrifice flavor; life is too short. But if I had sacrificed the enjoyment of food at the behest of these experts I would be plenty steamed about it.

So the larger question is what to make of all the misleading science we have been consuming for many years. Clearly, these changes show that doing this kind of science is really hard. Randomized trials give us the best data but it is hard to do them with human populations. You have to find a group of people you can watch for several years, randomly select those that are to change their diets, and then the subjects have to actually do what they’re told and report their actions honestly.  Good luck with all of that. So we are stuck with epidemiological studies in which it is hard to sort our causation from correlation.

I would be “nice” if we could take 10,000 kids, put them in quarantine, feed them experimental diets and monitor them for 70 years to see what happens. But there might be a couple of ethical problems with that experiment.

The fact of the matter is these new guidelines could turn out to be as misleading as the old ones.

The problem is not incompetent scientists or flaws in the scientific method. Science thrives on skepticism, on withholding belief until we have enough evidence to be reasonably certain about our conclusions. But our society won’t let science be skeptical. We crave health news because it has an immediate impact on our welfare and the media is all too happy to supply us with the latest theory long before the science is settled because it attracts eyeballs. Throw in corporate capitalism’s incentives to sell us whatever we think we need and we have a toxic medium in which misinformation can thrive.

None of that is likely to change. But it is becoming increasingly clear that food is not medicine. Trying to improve health by fine tuning your intake of nutrients—what Michael Pollan calls “nutritionism—is a mug’s game.

So I will continue to follow this sage advice: Everything in moderation including moderation. When there is something good to eat in the neighborhood I’ll be elbowing the Nutrition Nazis out of the way.