Sunday, May 2, 2010

Saturated Fat and the Popular Press

The May issue of the mainstream magazine Scientific American had an article saying that dietary carbohydrates are more important than fats in terms of heart disease risk.


Many people thought t
he news would never reach the mainstream press. But it finally has. The article cites the recent meta-analysis by Krauss and colleagues that suggested that the amount of saturated fat in the diet is not related to heart disease.

I would note several caveats. First, although some of the studies in the meta-analysis used food diaries to assess intake, others used the ubiquitous "food frequency questionnaires," which may not be accurate, as discussed here.

Second, Krauss et al. suggested that the effect of saturated fat may depend on what people substitute for the saturated fat. (This assumes that no one would want to decrease calories by simply eating less saturated fat, which is what makes the most sense to me.) Eating more unsaturated fat may decrease heart disease rates, whereas eating more carbohydrates may increase heart disease rates. Not everyone agrees with this, however.

Finally, the Scientific American article says it's mostly highly processed carbohydrates that are the villains, and the author writes, "some high-fiber carbohydrates are unquestionably good for the body." Many people do, in fact, question that statement, especially in relation to people with diabetes.

The author of the Scientific American article is not urging people to pig out on saturated fats. She says that current studies "do not suggest that saturated fats are not so bad; they indicate that carbohydrates could be worse."

It takes a long time for generally accepted ideas to be thrown out. Further studies may convince people that the "healthy whole grains" that people (including those with diabetes) are currently being urged to make the focus of their diets are just as bad as white bread, pasta, and sodas.

But for now, every little nail hammered into the brittle saturated fat hypothesis of heart disease helps. Saying that high-glycemic-index carbohydrates may increase heart disease risk is a step toward accepting the idea that all carbohydrates may do the same, especially in people with a genetic propensity to insulin resistance.

Publicizing the evidence in a mainstream popular magazine will help to spread the news, because the popular press operates with a herd mentality. If one mainstream news outlet carries a story, everyone else has to report on it too.

In fact, just today I got in the mail a copy of the Harvard Medical School Focus, which included a brief comment
titled "For Heart Health: More Polyunsaturated Fat, Fewer Refined Carbohydrates." This discusses both the Krauss paper cited above and another paper that supports the idea that substituting polyunsaturated fat for saturated fat instead of carbohydrate will reduce heart disease risks.

Perhaps the brittle saturated fat hypothesis of heart disease it will soon be shattered.


  1. Okay, carbs sort of take a hit but come on, this is a terrible paper. It suggests that whole wheat pancakes fried in margarine will decrease mortality. It suggests that riding on car hoods is dangerous, you would be safer riding on top of trains.

  2. I'm not sure I get your point. First, which paper are you referring to? I cited several. Second, whole wheat isn't a low GI food. Whole grains are considered such. Finally, Mozaffarian al. probably do think that a whole wheat pancake fried in trans-fat-free margarine would be better than a white-flour pancake fried in butter.

    I think you can have a healthy low-carb diet (reasonable amounts of meat/fish and low-carb vegetables) and an unhealthy low-carb diet (enormous amounts of fatty meats, eggs, and cheese with no vegetables, or meat and lots of low-carb junk food). If you don't have diabetes, the same could be said of low-fat diets.

  3. Gretchen,


    The following quote and response from you describes your spunk...

    One of the researchers said, "This is the first study to show that a high fat meal increases airway inflammation." No it didn't. It showed that a high-fat, high-calorie, high-carbohydrate, commercial junk-food meal increased airway inflammation.

    I agree with your statement 100% It's time we started eating more natural foods, and less processed junk. That's the real problem.

    Somebody needs to tell it like it is. You just did. Is anybody listening?

    It was good to meet you and David today. In case you forgot my blog is:

    Keep up the good work,

  4. Thanks, Patrick. Nice to meet you in Florida.