A new Tulane University study has sparked press reports suggesting that a low-carbohydrate diet is better than a low-fat diet for heart health. It turns out, however, that there was no actual low-fat diet in the Tulane study. The supposedly “low-fat” diet was a 30-percent-fat “chicken and fish” diet, based on the National Cholesterol Education Program guidelines. A 2005 study by the Physicians Committee had already shown that such a diet is not as effective as a low-fat vegan diet for long-term weight control.
In the new study, the “low-fat” diet group did not increase its fiber intake, suggesting that there was no increase in plant foods at all. Interestingly, the low-carbohydrate group actually reduced its reported fat intake, too, from 75.6 grams per day at baseline to 69.0 grams per day at 12 months. The study confirms that minimal changes in diet yield minimal results.
- Bazzano LA, Hu T, Reynolds K, et al. Effects of low-carbohydrate and low-fat diets: a randomized trial. Ann Intern Med. 2014. In press.