Many biological processes follow a set timetable, with levels of activity rising and dipping at certain times of the day.
Such fluctuations, known as circadian rhythms, are driven by internal "body clocks" based on an approximately 24-hour period - synchronised to light-dark cycles and other cues in an organism's environment.
Disruption to this optimum timing system in both animal models and in humans can cause imbalances, leading to such diseases as obesity, metabolic syndrome and fatty liver.
In studying the role of circadian rhythm in the accumulation of lipids in the liver in mice, Yaarit Adamovich from Weizmann Institute of Science and colleagues quantified hundreds of different lipids present in the mouse liver.
They discovered that a certain group of lipids, namely the triglycerides (TAG), exhibit circadian behaviour, with levels peaking about eight hours after sunrise.
The scientists were astonished to find that daily fluctuations in this group of lipids persist even in mice lacking a functional biological clock, albeit with levels cresting at a completely different time - 12 hours later than the natural schedule.
"These results came as a complete surprise: One would expect that if the inherent clock mechanism is 'dead,' TAG could not accumulate in a time-dependent fashion," said Adamovich.
"One thing that came to mind was that, since food is a major source of lipids - particularly TAG - the eating habits of these mice might play a role," Adamovich said.
Usually, mice consume 20 per cent of their food during the day and 80 per cent at night.
However, in mice lacking a functional clock, the team noted that they ingest food constantly throughout the day.
This observation excluded the possibility that food is responsible for the fluctuating patterns seen in TAG levels in these mice.