Meat, Fish and Chicken -- and Fats, Fats, Fats
(May 26, 2015)
How much to eat of which animals used to be a subject that nutritionists thought they had completely under control. Until just a short time ago, when some longstanding assumptions on the subject were challenged by actual Evidence.
To be fair, the original demonizing of red meat was based on some good research. But sadly, as so often happens in human affairs (and particularly in matters of health and medicine), we saw things that were not there and made a number of assumptions based on valid findings that were not themselves valid. How do we know that? MORE evidence.
“Science advances one funeral at a time,” Max Planck stated, and you know who HE was. (Well, maybe you don’t. I do – now that I’ve looked him up.) It happens that he was talking about the deaths of his scientific critics and not the deaths of elegant but mistaken theories. But those two are often much the same thing. It is terribly hard for any of us to let go of something we’ve accepted as fact. If you’ve based several decades of dietary advice to your patients on a fact that turns out to be possibly incorrect, it is especially hard to let go of. Because that means that you have not just been wrong for a very long time, but however unintentionally you have failed people who trusted you.
So sometimes it takes the passage of time plus the inevitable removal of believers from the scene to finally allow knowledge to advance to the next stage. Whatever the reason, that is what is happening now, with quite a lot of sound and fury, in the area of dietary fat.
For the last 50+ or so years, whenever the science-minded talked about nutrition they tended to speak not of food but of the components of food – vitamins, fiber, colored mini-marshmallows, etc. This was at least partly because for centuries now we have been breaking things into their component parts in order to study and better understand them.
That kind of reasoning is called “reductionist” and it served us pretty well for a while, but recently it has run us into a wall. In fact, in the area of nutrition, on a practical and useful level it is now failing miserably. Different nutrients influence each other and the body in so many different ways at so many different levels that the complexity has become overwhelming – and the information obtained often of little use because all it does is create MORE questions.
Much nutritional research therefore now focuses on the effects produced by a particular food, or even on a style of eating, instead of trying to reduce everything down to some unwieldy basic components. I am blabbering on about this because this is what happened to the basic idea behind the eat meat/fish/poultry rules – the reductionism we applied to the area turns out to have produced some serious error.
Because animal protein is complete and as long as you get enough of it you don’t need to sorry about its nature any more than that, dietary advice on animal foods focused on its fat content – both what kind of fat and the amount that a typical serving contained. And red meat fails on both of these counts. So, until recently the dietary advice was to keep the consumption of red meat to a minimum if you couldn’t eliminate it from your diet altogether.
Some decades ago, a few studies found that people who ate a lot of red meat had a lot more heart disease, a problem that had been rapidly increasing in incidence since the early 20th century. And since that heart disease manifests as fatty cholesterol deposits in the arteries, and a few other studies showed that the more saturated fat people ate the more heart disease they had, the assumption was made that it must be the saturated fat and cholesterol found so abundantly in red meat that was behind the increase of heart disease. Thus began the era of nagging to not just eat chicken and fish instead of meat, but also to avoid the consumption of saturated fat and cholesterol everywhere it was found.
Red meat was bad because it had saturated fat and cholesterol. Chicken was better because it had only partly saturated fat and little/no cholesterol. Fish (and liquid vegetable oils, which are polyunsaturated and contain no cholesterol at all) were supposed to be the best fats, period. That was the mantra, and that's still as far as most people have gotten, because when the discussion of individual fatty acids became part of the conversation most people became lightheaded and went to see what was on television.
The mistake was that we didn’t look at the science of foods-with-fat, as opposed to just fat. I’ve read studies wherein people drank beverages with various compositions of saturated and/or unsaturated fats, and these studies were meant to tell us something useful about foods that contain fat. Well, they really don’t. When we eat a food that contains a particular nutrient, everything in that food – or in that meal – can affect how your body deals with that nutrient. Broccoli for example contains carcinogens which would smite you in a heartbeat if you consumed them individually, as do many other plants which manufacture them as natural pesticides. This concept of a whole food being different from a collection of unrelated food parts apparently IS rocket science, because it was a fact that for many years was almost universally ignored.
So now the whole field of dietary fat is embroiled in controversy, which no one really likes. People like certainty, and scientists like to look as though they know what they're talking about. But the fundamental nature of science is that we are never certain of anything. We only have a preponderance of the evidence that points in one direction or the other. You only have things cut and dried and absolutely certain in politics. Ha.
As of last week, the American Heart Association was still telling us to avoid red meat and asserting that “cholesterol and saturated fat can raise your blood cholesterol and make heart disease worse”. Well, that is kind of true, but not absolutely. Focusing your animal protein consumption on properly prepared chicken and fish instead of cow is certainly not going to get you in trouble. But their basic advice is genuinely out of date and there’s a lot more going on that we need to look at – next time.
--dr. diane holmes
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