Preventive Medicine Column
Dr. David L. Katz
A commentary in the current issue of the British Medical Journal (BMJ) suggesting that saturated fat is not really so bad after all has the media buzzing. My most recent Google search of “saturated fat” limited to news retrieved 20,000 sites. Since the new paper is just a commentary- one doc’s opinion- and not a new study, and since this opinion has been asserted many times already, I’m not sure I really get the reaction- but hey, I just work here. Let’s deal with it.
Is it, in fact, time to absolve saturated fat? No, it’s not. But then again, it was never time to demonize it in the first place. I will lay out my case that we are ill-served to think of saturated fat as either scapegoat, or martyred saint.
The case against saturated fat, its implication in the development of atherosclerosis, inflammation, and chronic diseases, notably heart disease, involves a vast expanse of research over many years by thousands of researchers around the world. But those who first advised limiting saturated fat intake had not yet imagined Snackwell cookies! The initial research was comparing the health of people eating meat and cheese and ice cream, to the health of people eating mostly plants, and to other people eating lots of plants along with nuts, and seeds, and fish. Nobody was eating low-fat junk food, because it hadn’t been invented yet.
When it was invented, to exploit the interest in limiting fat intake in general, and saturated fat intake specifically, it created a whole new way of eating badly. Yes, we can reduce our intake of saturated fat and replace it with sugar and starch and glow-in-the-dark food chemicals, and not wind up healthier. Is anyone really shocked about this?
Saturated fat is not one food component; it’s a category. Just as polyunsaturated fats include the anti-inflammatory omega-3s, and the pro-inflammatory omega-6s (and even that is over simplified), so does the saturated fat class contain a diversity of members. One of them, stearic acid, found in dark chocolate among other places, is now clearly established to be innocuous. Another, lauric acid, predominant in coconut oil among other places, may prove to be as well. But still others, such as palmitic acid and myristic acid, appear to be substantially guilty as charged, contributing to inflammation and atherosclerosis. The body of relevant evidence is expansive.
What this means is that even if there are harms attached to some saturated fats, summary judgment against the whole clan was never valid. The combination of parsing and over-simplification invites the devils in the details to run amok. That clearly happened here. Some saturated fat simply isn’t harmful. Some is.
The new commentary states explicitly that the percent of calories from fat in the typical American diet went down over the years, but total fat intake did not. This leads inexorably to only one conclusion: total calorie intake went up, diluting down the percent of calories coming from fat.
So, we never really cut our fat intake-we simply diluted it as a percent of total calories by eating more sugar and starch. We kept the saturated fat, replaced some of it in time with trans fat, and applied a generous icing of starch and high-fructose corn syrup. And yet, amazingly, we didn’t wind up healthier. Well then, yes, clearly saturated fat must be good for us! Or not.
The world’s best diets, associated with the world’s best health outcomes, encompass both higher and lower levels of total dietary fat. But all such diets are relatively low in saturated fat, as our native Stone Age diet was thought to be. There is no need to obsess about cutting saturated fat. If we choose wholesome foods, we will wind up with better diets and better health. Incidentally, our saturated fat intake will not be more than moderate.
Demonizing saturated fat never helped us much. Canonizing it now won’t help us any either. All who share a concern for eating well and the health advances that can come from it must band together to renounce the perennial branding of this, that, or the other food component as scapegoat, or saint.
It is, and always was, the big picture- the overall dietary pattern, and for that matter lifestyle pattern- that matters. We could cut saturated fat and eat better, or worse, depending on what we eat instead. A bounty of science along with an application of sense points very reliably to variations on the theme of optimal eating for Homo sapiens. We could all get there from here, and by so doing, add years to life, add life to years, and love food that loves us back. None of this will happen though if we replace the follies of history with old mistakes in new directions.
Dr. David L. Katz