Time-restricted feeding entrains daily rhythms of energy metabolism in mice.
Level 5 - mechanism / opinion, no new human data
Preclinical animal model (mice)
PubMed 16384858 · doi:10.1152/ajpregu.00775.2005
What was done
Researchers continuously measured energy metabolism, oxygen consumption rate (VO2), and respiratory quotient (RQ) in mice under 12:12-h light-dark cycles before, during, and after time-restricted feeding (restricted to daytime/light phase). They assessed metabolic parameters, core body temperature, and liver clock gene expression in mice fed standard or high-fat diets ad libitum or restricted to daytime hours. The abstract did not state the sample size.
What was found
Mice fed ad libitum exhibited standard daily rhythms for VO2 and RQ (high during the dark phase, low during the light phase). Daytime-only feeding reversed these energy metabolism rhythms beginning at the first fasting night and reversed core body temperature rhythms within a few days. Six days of restricted feeding shifted hepatic clock gene expression phases by 8–10 h. Ad libitum high-fat feeding caused the RQ rhythm to disappear by day 6 without shifting liver clock genes, whereas daytime high-fat feeding reversed both VO2 and RQ rhythms and significantly shifted liver clock genes. Specific quantitative values for metabolic rates were not reported in the abstract.
Why it matters
The findings demonstrate that food timing, rather than diet composition alone, entrains peripheral circadian clocks and whole-body metabolic rhythms in mice, establishing oxygen consumption rate as a sensitive, noninvasive indicator of hepatic entrainment.
Limits
The investigation was conducted exclusively in a nocturnal rodent model, limiting direct applicability to diurnal humans. Sample size, numerical metabolic measurements, and confidence intervals were omitted from the abstract. Central circadian pacemaking in the brain was not evaluated.
Cited by
- contradicts The term 'time-restricted feeding' (or time-restricted eating) was discovered and coined in Dr. Satchin Panda's laboratory publication.