The DEPTH trial is a randomized clinical trial examining how time-based energy intake goals (chrononutrition) applied within a 12-month obesity care lifestyle intervention influences percent weight loss, dietary temporal patterns, sleep regularity, and appetite regulation.
The DEPTH trial will randomize 174 adults to one of three lifestyle intervention conditions differing in timing of energy intake distribution.
All three intervention arms share five common dietary goals and a physical activity target within a 33-session obesity care lifestyle intervention.
The DEPTH-Morning arm is designed to front-load energy intake, consuming 70% of daily energy in the first six hours of the eating window.
The DEPTH-Evening arm is designed as the mirror opposite of DEPTH-Morning, adopting an afternoon/evening-loaded energy distribution.
The trial will assess four primary outcome domains at four time points across 12 months.
The study is framed within the concept of chrononutrition, positioning time-based energy intake goals as a component of obesity care lifestyle intervention.
This paper describes the design and rationale of a clinical trial called DEPTH (Daily Eating Patterns for Total Health), which is testing whether the timing of when people eat their calories during the day affects weight loss and related health outcomes. All participants in the study follow the same basic healthy eating plan — limiting calories to 1200-1500 per day, keeping fat intake low, eating within a 12-hour window, and being physically active — but one group is asked to eat most of their calories earlier in the day, another group later in the day, and a third group has no specific guidance on when to eat their calories within the window. This research suggests that not just what you eat, but when you eat it, may play a role in obesity treatment outcomes. The study is grounded in the science of chrononutrition, which examines how the timing of food intake interacts with the body's internal clock. By comparing morning-loaded versus evening-loaded eating patterns, the trial aims to determine whether front-loading calories earlier in the day leads to better weight loss, improved sleep regularity, and better appetite control compared to eating more calories in the afternoon and evening. The trial will follow 174 adults for 12 months, measuring weight, dietary patterns, sleep, and appetite at multiple time points. Because this is a protocol paper rather than a results paper, no findings on outcomes are yet available — the study is describing its plan and methods. When completed, this research could help inform whether specific guidance on meal timing should become a standard part of obesity treatment programs.
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Upload Your LabsRaynor H, Berlin K, Bond D, Cardoso C, Carskadon M, Ehrlich S, et al.. (2026). Rationale and protocol for time-based energy intake goals within an obesity care lifestyle intervention: Daily eating patterns for total health study.. Contemporary clinical trials. https://doi.org/10.1016/j.cct.2026.108356