Release recently of the federal government’s latest diet guidelines reinforces, once again, what an exercise in futility it all is, as foods continue to get kicked off the list and then reinstated. . If we’ve learned anything from the relentless discussion and study of food over the decades, it’s that what we know for certain about the relationship of diet to health and longevity is next to nothing. The expertise various people claim is a stew of superstition, old wives’ tales, conventional wisdom, pseudo-science, and charlatanism. Study after study refutes the findings of the one that came before and is refuted by the one that comes after, even as the media, which never met a study it didn’t like, reports breathlessly on the latest “findings,” caring not in the least if the study has any scientific validity or if the numbers it reports have any actual meaning. Is there a subject that has more junk-science jabberwocky associated with it than that of diet?
My theory is that since everyone wants to postpone for as long as possible (or maybe even eliminate) the inevitable catastrophe of death, they’re eager to embrace the notion that something as relatively simple and controllable as what they put in their bodies in the form of food is a major player in that process. Eat this, live long and prosper. Don’t eat that, live long and prosper. If only. There doesn’t seem to be any real science behind any of it, but that doesn’t stop people from asserting unequivocally that food A is “good for you” and food B is not. What science there is – the interminable revolving door of “studies” – routinely reverses conclusions about the healthfulness of individual food items, food categories, food chemistry, and food properties, and then reverses them again.
Eggs could be exhibit A in this phenomenon. Leaving aside the whole business of the relationship of blood cholesterol to heart disease – a relationship that is now being characterized as not very well understood – there has been a 180-degree reversal of the thinking on how dietary cholesterol affects blood cholesterol. It doesn’t, the experts now tell us. So go ahead and eat eggs, the yolks of which contain a lot of cholesterol. You’ll recall that not so long ago, it was understood that egg-eating should be limited because of the cholesterol they contain; and not so long before that, they were to be strictly limited if not eliminated from the diet altogether; and not so long before that, they were nature’s most nearly perfect food. Which they are again. Oh, no, wait. That was milk, the full fat version of which, thought to be something akin to poison for decades, has now been rehabilitated, even as the entire business of fat in the diet has been completely rethought. (Fat, the substance, was equated with fat, the condition, and Big Food made billions, and still does, by peddling stuff as low-fat or fat-free.)
The list goes on and on. Various vitamins had certain effects and then they didn’t. And then they did again. Food fiber prevented bowel cancer, until it didn’t. Fish oil was a major player in good health and then, not so much. Red meat was good, then bad, then good, then bad. (I think it’s good now. Or at least pretty good.) Protein, carbohydrates – good, bad, good, bad. Dark chocolate, red wine are good for the heart because of the resveratrol they contain, say various studies. Then various other studies say we’d have to ingest 73.5 lbs. of resveratrol a day (or some such thing) for it to have any effect. Coffee. Beer. Good. Bad. Good. Bad. A study shows something-something reduces the risk of heart disease by 17-percent. But what does that mean? That I will have a heart attack at age 81 and 15 days instead of age 81 and 14 days?
An interesting sidebar topic to all of this is “fast” food, a category that is generally ranked somewhere between unwholesome and poisonous in the popular culture The problem: No one really knows what the term means. Is it that the food is cooked fast? Eaten fast? Both? Or that it’s produced and sold by large chain restaurants that have drive-through windows. What difference does it make? Answer: None. It’s just food. The typical fare – beef, cheese, and bread – is served up in diners, fancy restaurants, and homes around the world, daily. There is zero true scientific evidence that people who refrain from eating these things are any healthier or live any longer than anybody else. The demonization of “fast food” is completely irrational.
Bottom line: There is a good deal of knowledge – science – out there about the properties of the food we eat, but not much about how those properties, individually and in combination, relate to health and longevity. “Good for you” and “not good for you” are not science or knowledge-based concepts and are therefore essentially meaningless. Same with the term “healthy diet.” It appears the only thing we know with any degree of certainty about eating’s relationship to good health is this: Don’t do very much of it.
