Letters Section Editor: Jody W. Zylke, MD, Senior Editor.
Author Affiliation: University of Washington School of Dentistry, Seattle (firstname.lastname@example.org).
To the Editor: The study by Dr Ebbeling and colleagues1 contributes to the understanding of dietary modulation for energy expenditure and may have implications for the prevention and treatment of obesity. However, in the accompanying Editorial,2 Bray asserted that “Resting energy expenditure (REE) and total energy expenditure (TEE) declined with all diets, but the decrease was significantly greater with the low-fat diet than with the other 2 diets.” In fact, the pairwise energy expenditure comparisons between the very low-carbohydrate diet and the low-fat diet were not reported, and the footnotes in Table 3 in the article indicated that differences in REE and TEE were not significant when comparing either the low-fat vs the low–glycemic index diet or the low–glycemic index vs the very low-carbohydrate diet. Rather, the main finding, based on statistical adjustment using a complex regression model followed by tests for linear trend across diets ordered by hypothesized but unmeasured effects on glycemic excursions, was simply that “ . . . weight loss resulted in decreases in REE and TEE that were greatest with the low-fat diet, intermediate with the low–glycemic index diet, and least with the very low-carbohydrate diet.” This conclusion is a good deal more nuanced than one permitted by identification of reliable pairwise differences among the diet groups.
Kaiyala KJ. Dietary Composition During Weight-Loss Maintenance. JAMA. 2012;308(11):1087. doi:10.1001/2012.jama.11617