I want to discuss a couple of interesting follow ups from the Israeli low-carb study that I posted on a couple of weeks ago. But before I do, I’ve got to apologize for the lack of posting and comment answering for the past week or so. Since we got back from our trip our computers have been acting up. Our internet connection keeps drifting in and out. With the blogging software we use, if we try to save during a time that the internet isn’t connected, everything new gets lost. MD didn’t know that, so she actually managed to put up a post in between outages, which, I suppose, is the luck of the ignorant. I haven’t because I didn’t want to take the risk. Instead I’ve been beating my head against the ground trying to solve the problem. I finally gave up and called the cable company. The guy came out today and discovered that it was a faulty cable modem. He replaced it, so I’m back in business with a lot of catching up to do on all fronts.
One of the questions many people had about the Israeli study was why the recommendation to follow a vegetarian low-carb diet instead of a more meat-heavy low-carb diet? And, in view of this recommendation, what was the final diet the subjects on the low-carb arm consumed? [full text of the study]
Eric Westman, M.D. from Duke University corresponded with the lead author of the paper and asked these questions. Here is the response:
This is kind of funny that some could think of a “vegetarian low-carb” diet. Is it a new suggested strategy? could be interesting idea but this wasn’t the case here. Our low-carb diet was based on Atkins, the participants read the book and the recipes were more or less comparable to what you know in the states. Beef is the main red meat. What could be different? People here would not mix in the same meal meat and butter, a salad is considered a very rich one and not a lettuce based, and the main dressing is olive oil. As for beverages, same industry that makes money everywhere.
For example, a plate could include : fish or fried/not bread coated chicken/or red meet, broccoli and mushrooms coated with eggs, roasted eggplants, vegetable salad (peppers, cucumber, green leaves, not lettuce) with olive oil dressing. I understand that some of the low-fat people find it hard to believe that such a low-carb diet was tremendously favorable within 2 years in a well designed study, but these are the facts and the science of tomorrow, with the next long term studies in the pipeline, may confirm or not these findings.
Best regards, Iris [Shai]
As I mentioned in my previous post, I figured it had something to do with the dietary restrictions followed by observant Jews. For those who don’t know, one of the major dietary restrictions is the avoidance of mixing meat and dairy products. Observant Jews go to great extremes in adhering to this tenet of Jewish law. They have separate dishes, silverware, and pots and pans for meat and for dairy. Those who can afford it have two dishwashers – one for meat, one for dairy. Kosher restaurants are either meat or dairy. If you go to a dairy kosher restaurant you can have all the milk, butter, cream, ice cream, cream sauce, etc. you want. You can have pasta, fish (not considered meat), and pretty much anything not made of meat. Cheese, although obviously a dairy product, is often missing because cheese is made using rennet, which is an animal product and considered meat. At a kosher meat restaurant you can eat all kinds of meat (as long as it’s kosher), but you can’t have butter or cream for your coffee or any kind of cream sauce. Or anything made from milk or cream. You can have faux dairy products, i.e., margarine and trans fat-laden non-dairy creamer for your coffee or in desserts. There are pretty high rates of heart disease in Israel, and many believe one of the causes is the large amount of trans fats Israelis consume in an effort to follow Jewish law.
John Tierney in his New York Times blog posted an interviewed with Gary Taubes about the findings of this low-carb study with respect to saturated fats. Here is what Gary had to say:
These trials are fundamentally tests of the hypothesis that saturated fat is bad for cholesterol and bad for the heart. They’re not just about which diet works best for weight loss or is healthiest, but what constitutes a healthy diet, period. (This is the point I made in my Times Magazine story six years ago). Specifically, these low-fat/low-carb diet trials, of which there are now more than half a dozen, test American Heart Association (A.H.A.) relatively low-fat diets against Atkins-like high-saturated-fat diets.
In this last test, the A.H.A. diet was about 30 percent calories from fat, less than 10 percent calories from saturated fat; the low-carb diet was almost 40 percent calories from fat, around 12.5 percent saturated fat. In this particular trial, as in all of them so far, the high-saturated-fat diet (low-carb or Atkins-like) resulted in the best improvement in cholesterol profile — total cholesterol/H.D.L. In this Israeli trial, the high-saturated-fat diet reduced L.D.L. at least as well as the did the A.H.A. relatively low-fat diet, the fundamental purpose of which is to lower L.D.L. by reducing the saturated fat content.
So here’s the simple question and the point: how can saturated fat be bad for us if a high saturated fat diet lowers L.D.L. at least as well as a diet that has 20 to 25 percent less saturated fat?
It could be argued (and probably will be) that the effect of the saturated fat is confounded by the reduction in calories, but the A.H.A. diet also reduces calories and in fact specifies caloric reduction while the low-carb diet does not. It will also be argued, as Dean Ornish does, that the source of the saturated fat was not necessarily meat or bacon, but beans or other healthy sources.
But the nutritional reason why meat has been vilified over the years, is that it’s a source of unhealthy saturated fat. It’s not that meat per se is bad — unless you buy the colon cancer evidence, which has always seemed dubious — it’s that the saturated fat in meat makes it bad. So the argument about the source of the saturated fat is irrelevant.
The question hinges on whether saturated fat raises cholesterol and causes heart disease. One way or the other this trial is a test of that hypothesis. It’s arguably the best such trial ever done and the most rigorous. To me that’s always been the story. If saturated fat is bad for us, then these trials should demonstrate it. They imply the opposite.
Why does the A.H.A. continue to insist that saturated fat should be avoided, if these trials repeatedly show that high saturated fat diets lead to better cholesterol profiles than low-saturated fat diets? And how many of these trials have to be done before the National Institutes of Health or some other august institution in this business re-assesses this question? After all, the reason the food guide pyramid suggests we eat things like butter and lard and meats sparingly (and puts them high up in the pyramid) is that they contain saturated fat. This is also the reason that the A.H.A. wants to lower even further what’s considered the safe limit for saturated fats in the diet.
It’s nice to know that at least one person at the New York Times has good sense (nutritionally, at least). Tierney had a piece in today’s Science section that debunks a handful of what he considers scientific myths that people spend time worrying about. I don’t know if I agree with him that all these ‘myths’ are really myths, but I completely agree with his take on the hot dog.
Killer hot dogs. What is it about frankfurters? There was the nitrite scare. Then the grilling-creates-carcinogens alarm. And then, when those menaces ebbed, the weenie warriors fell back on that old reliable villain: saturated fat.
But now even saturated fat isn’t looking so bad, thanks to a rigorous experiment in Israel reported this month. The people on a low-carb, unrestricted-calorie diet consumed more saturated fat than another group forced to cut back on both fat and diet, but those fatophiles lost more weight and ended up with a better cholesterol profile. And this was just the latest in a series of studies contradicting the medical establishment’s predictions about saturated fat.
If you must worry, focus on the carbs in the bun. But when it comes to the fatty frank — or the fatty anything else on vacation — I’d relax.
On a you’ve-just-got-to-shake-your-head note, go back to the Tierney piece containing the long quote from Gary and read through the hundred plus comments that follow. Doing so gives you an idea of the total nutritional ignorance out there. These are the misinformed people that politicians and bureaucrats pander to when establishing the nutritional guidelines. A sorry state of affairs indeed.