I was pretty excited to read several links in my email feed about a study just published in The Annals of Internal Medicine. Funded by the National Institutes of Health, it was (yet) a(nother) randomized controlled trial (RCT), the gold standard of studies, showing the superiority of low-carb over low-fat dieting for losing weight. For another – and this was the hypothesis to be tested – it showed the superiority of low-carb over low-fat in improving heart disease risk, using all the classical markers for determining that risk.
The study, “Effects of Low-Carbohydrate and Low-Fat Diets: A Randomized Trial,” was performed at the Tulane University School of Public Health in New Orleans. The lead investigator was Lydia Bassano, MD, PhD. It enlisted a diverse population of 148 men and women without either clinical cardiovascular disease or diabetes. The study DESIGN: “A randomized, parallel group trial. The OBJECTIVE: “To examine the effects of a low-carbohydrate diet compared with a low-fat diet on body weight and cardiovascular risk factors. The ABSTRACT can be view here. Full access will cost you (and me) $29.95.
The study participants were randomly selected to be placed in one of two diet groups and had no restrictions on calories. They were also told to make no changes in physical activity. The target for the low carb group was to eat less than 40 grams of carbohydrate a day. The target for the low-fat group was to eat less than 30% of daily energy intake from total fat and less than 7% from saturated fat. Both groups received dietary counseling from an RD and were tested at baseline, three months, six months, and twelve months. About 80% of the participants finished the one-year study.
The CONCLUSION was two sentences. The first is declarative and absolute: “The low-carbohydrate diet was more effective for weight loss and cardiovascular risk factor reduction than the low-fat diet.” The second, “Restricting carbohydrates may be an option for persons seeking to lose weight and reduced cardiovascular risk factors,” is couched with the word “may.” Perhaps this is more palatable to conventionally trained physicians (who are not trained in nutrition) and to the nutritional professionals who are but have been misled, along with the physicians, by half a century of poorly performed research and pure propaganda from public health policy makers and the perfidious players in the processed food business.
The results, in layman’s terms, have now been broadcast widely. Jimmy Moore (Livin' La Vida Low-Carb) and Andreas Eenfeldt (The Diet Doctor) were among the first. But The New York Times, The Wall Street Journal (by subscription), National Public Radio, Time Magazine, CBS News, and the Washington Post, were quick to follow. By now the story is so widely disseminated that in some media it has been reinterpreted to the point that it is hardly recognizable. So before or in case a distorted version of this story reaches your ears and eyes, let me apprise you of the principal findings.
● Triglycerides – the type of fat that circulates in your blood – “plunged” on the low-carb diet (NYT)
● HDL – the so-called good cholesterol – rose more sharply than it did for people on the low-fat diet (NYT)
● Total Cholesterol/HDL ratio – an important maker of heart disease risk – improved (NYT)
● Chronic systemic inflammation – as measured by hs-CRP (C-reactive protein) also “plunged.” (NYT)
● Blood pressure, total cholesterol and LDL, the so-called bad cholesterol, showed little change in both groups. (NYT)
The NYT article was clearly open-minded and its view of the results positive. Dr. Allan Sniderman, a professor of cardiology at McGill University in Montreal and not associated with the study, was quoted as saying that the decrease in [heart disease] risk on the low-carbohydrate diet “should translate into a substantial benefit.” He added, importantly,
“One important predictor of heart disease that the study did not assess was the relative size and number of LDL particles in the bloodstream. Two people can have the same overall LDL concentration, but very different levels of risk depending on whether they have a lot of small, dense LDL particles or a small number of large and fluffy particles.”In contrast to the very well reported and balanced story in the New York Times, the Fox News Channel had a cardiologist on the “Fox and Friends” program in the morning who failed to mention the first four clearly beneficial outcomes of the trial, in terms of heart disease risk, listed above. He did begrudgingly acknowledge, with genuine surprise it seemed to me, that total cholesterol and LDL (the so-called bad cholesterol) stayed about the same for people in each group. Maybe the more conservative Fox News Network was interviewing a more conservative cardiologist. Frankly, it seems to me that he (and most of the conservative medical establishment) has plaque on the brain, not in their arteries.