Scientists have discovered that genetics and diet together shape the circadian rhythms of fat metabolism. A study in mice showed that fat metabolism depends on the time of day and hereditary factors.

The results of the study were published in the journal Cell Metabolism.

However, the size of fat droplets in the liver changed throughout the day only in mice with an active ESRRγ gene, a so-called non-classical circadian rhythm regulator.

In its absence, the daily connections between different DNA segments and gene activity regulators in the liver are disrupted, and fat metabolism is disrupted.

The scientists also found that diet affects gene expression rhythms, but not equally for everyone. On a high-fat diet, gene activity in the liver changed in different ways: some genes maintained their rhythm, others lost it, and still others acquired it.

Together, genetics and nutrition control more than 80% of the rhythmic interactions between enhancers (regulatory regions) and promoters (transcription initiation sites) of genes.

The study raises the prospect of personalized chronotherapy—the selection of the time of food intake, medication, or procedures in accordance with a person's genotype to optimize metabolism and health benefits. According to the authors, the principles identified for the liver and fat metabolism can probably be applied to other organs and diseases.