SciAM on Carbs

http://www.scientificamerican.com/article.cfm?id=carbs-against-cardio


What's the takeaway?  That low fat gig you were pretty sure didn't work, didn't work in these studies either (note, several of the cited studies were observational).  Those who ate the most fat had better health markers than those eating less fat.  In short, these types of results make the government's dietary recommendations look as silly as I've thought they were for years.


But even when they get it right, they get it wrong:
Nobody is advocating that people start gorging themselves on saturated fats, tempting as that may sound. Some monounsaturated and polyunsaturated fats, such as those found in fish and olive oil, can protect against heart disease.  What is more, some high-fiber carbohydrates are unquestionably good for the body. But saturated fats may ultimately be neutral compared with processed carbs and sugars such as those found in cereals, breads, pasta and cookies.


Of you should eat veggies if you like them, but for the sake of precision, exactly what would it take to prove that 'some high fiber carbohydrates are unquestionably good for the body'?  It would take a very carefully planned and executed intervention study, one that has not been done.  As my friend David "Chef" Wallach said, "As soon as someone claims there is 'proof' in dietary science, you know they have no grasp on what the word proof means."

The finding joins other conclusions of the past few years that run counter to the conventional wisdom that saturated fat is bad for the heart because it increases total cholesterol levels. That idea is “based in large measure on extrapolations, which are not supported by the data,” Krauss says.

One problem with the old logic is that “total cholesterol is not a great predictor of risk,” says Meir Stampfer, a professor of nutrition and epidemiology at the Harvard School of Public Health. Although saturated fat boosts blood levels of “bad” LDL cholesterol, it also increases “good” HDL cholesterol. In 2008 Stampfer co-authored a study in the New England Journal of Medicine that followed 322 moderately obese individuals for two years as they adopted one of three diets: a low-fat, calorie-restricted diet based on American Heart Association guidelines; a Mediterranean, restricted-calorie diet rich in vegetables and low in red meat; and a low-carbohydrate, nonrestricted-calorie diet. Although the subjects on the low-carb diet ate the most saturated fat, they ended up with the healthiest ratio of HDL to LDL cholesterol and lost twice as much weight as their low-fat-eating counterparts.

Stampfer’s findings do not merely suggest that saturated fats are not so bad; they indicate that carbohydrates could be worse. A 1997 study he co-authored in theJournal of the American Medical Association evaluated 65,000 women and found that the quintile of women who ate the most easily digestible and readily absorbed carbohydrates—that is, those with the highest glycemic index—were 47 percent more likely to acquire type 2 diabetes than those in the quintile with the lowest average glycemic-index score. (The amount of fat the women ate did not affect diabetes risk.) And a 2007 Dutch study of 15,000 women published in the Journal of the American College of Cardiology found that women who were overweight and in the quartile that consumed meals with the highest average glycemic load, a metric that incorporates portion size, were 79 percent more likely to develop coronary vascular disease than overweight women in the lowest quartile. These trends may be explained in part by the yo-yo effects that high glycemic-index carbohydrates have on blood glucose, which can stimulate fat production and inflammation, increase overall caloric intake and lower insulin sensitivity, says David Ludwig, director of the obesity program at Children’s Hospital Boston.