This is like a boxing match going on thirty-something rounds, with the same guy getting knocked out in every round! The number of studies comparing low fat diets to low carbohydrate diets is ever growing, and the results seem to repeat themselves. The low carb diet just about always wins.
My silly boxing analogy aside, let’s not underestimate the importance of studying diet and its result on weight and cardiovascular risk factors, thoroughly and repetitively. As the CDC words it, “Obesity is common, serious, and costly.” About a third of US adults are obese. Obesity costs money ($147 billion dollars in 2008), and kills people. Obesity is associated with hypertension, high cholesterol, heart attacks, cancer, and death.
In May of 2003, two studies comparing low fat to low carb diets were published in The New England Journal of Medicine. Both showed that the participants on the low carbohydrate diet lost more weight, more quickly. One of them also demonstrated that the low carbohydrate group had a greater reduction in triglycerides and blood sugar.
Since that well known May, 2003 issue of the NEJM, scores of other studies have been published. For example, in 2007, a group from Stanford University Medical School compared a handful of trendy diets (Atkins, Zone, Ornish, LEARN). Wouldn’t you know it, once again, the low carbohydrate group came out on top (at least for the first six months).
Now let’s look at the most recent study together. The paper is titled Effects of Low-Carbohydrate and Low-Fat Diets. A Randomized Trial. It was published in the September 2, 2014 issue of the Annals of Internal Medicine, a well-respected medical journal published by the American College of Physicians. The study, funded by the NIH, came out of Tulane, Kaiser Permanente, and Johns Hopkins. The authors’ gripe, so-to-speak, is that previous trials were either too small, too short, or did not include a diverse and healthy population. So, in this study, participants included black people, white people, men and women. Interestingly, the participants were relatively healthy compared to those in previous trials. That is, they did not have diabetes, cardiovascular disease, or kidney disease. The results? Once again, in every single measure, low carbs won. The low carbohydrate diet beat the low fat diet in weight loss, fat mass, HDL/Chol ratio, HDL increase, and triglyceride decrease. Most of the differences, by the way, lasted for the full twelve months of the trial.
I would like to propose the following practical conclusions from this study:
1. By avoiding excess carbohydrates in your diet, you can help prevent heart disease.
2. Despite previous anecdotes, low carbohydrate diets, with relatively liberalized fat, will not raise your cholesterol. In fact, you can expect it to decrease.
3. Low carbohydrate diets are not just for diabetics. Non-diabetics too derive significant cardiac risk reduction.
4. The old adage that red meat and chicken soup clog your arteries is probably wrong. It was the rice and potatoes!
I hope that’s helpful.
Dr. Van Dam