To the Editor In the Diet Intervention Examining The Factors Interacting with Treatment Success (DIETFITS) randomized clinical trial, the investigators concluded that there was no significant difference in weight change between a healthy low-fat diet vs a healthy low-carbohydrate diet.1 At baseline, both groups consumed a comparable percentage of daily calories from fat: 34.8% for the low-fat group and 36.0% for the low-carbohydrate group. At the conclusion of the 12-month study period, the percentage of daily calories from fat was 28.7% in the low-fat group and 44.6% in the low-carbohydrate group. Although the percentage of daily calories from fat was reduced from 34.8% to 28.7% in the low-fat group, a diet composed of 28.7% of the daily calories from fat is a high-fat diet.