Research paper
Ravussin E, Beyl RA, Poggiogalle E, Hsia DS, Peterson CM. Early time-restricted feeding reduces appetite and increases fat oxidation but does not affect energy expenditure in humans. Obesity (Silver Spring). 2019;27(8):1244-1254. doi:10.1002/oby.22518
Why we cite it
A whole-room indirect-calorimetry crossover trial — 11 adults with overweight, 4 days per condition — testing whether early time-restricted feeding acts through energy expenditure or through intake, with food intake and meal frequency matched. That matching is what makes it worth citing.
*Corrected 2026-09-02 (card 6NM98H): this section said the trial ”definitively showed” the mechanism and was ”directly demonstrating” hunger adaptation. Eleven people for four days does not license definitively, and the paper’s own title carries its central null: ”…but does not affect energy expenditure in humans.” The design is strong and the sample is eleven — those are both true and the section had only the first.
The Extracted knowledge below is careful and should be preferred over this section wherever they differ. It gives the N, the crossover design, the hunger amplitude with its P value, and the non-significant results in the right register — ”tended to increase fullness (p = 0.06–0.10) and decrease desire to eat (p = 0.08).” A page reaching for this record should read past the Contribution. The headline finding for the project: despite a longer daily fast (18 hours vs. 12 hours), eTRF decreased* ghrelin by 32 pg/mL and made hunger more “even-keeled” — directly demonstrating that the hunger system adapts to a consistent eating window. The null result on 24-hour energy expenditure (Δ=10 kcal/day, p=0.55) is equally important: it refutes the popular claim that fasting “boosts metabolism.” Together with Natalucci et al. 2005 (csh02, showing ghrelin maintains meal-related patterns during fasting) and Cummings et al. 2001 (csh01, showing preprandial ghrelin surges), this paper completes the hunger-adaptation evidence base: hunger is scheduled, adapts to new patterns, and stabilizes with consistency.