Scientific study explains why you should eat at the right time


When one eats may be as important as what one eats!

Biological clock also known as the circadian clocks are found in living things from bacteria to flies and humans, controls our rhythms of sleep, activity, eating and metabolism. It is like a daily calendar, telling the body what to expect, so it can prepare for the future and operate optimally.

New research at the Weizmann Institute of Science and in Germany led by Dr. Gad Asher, which recently appeared in the Proceedings of the National Academy of Sciences (PNAS), suggests that the cells’ power plants – the mitochondria – are highly regulated by the body’s biological, or circadian, clocks. This may help explain why people who sleep and eat out of phase with their circadian clocks are at higher risk of developing obesity, diabetes and metabolic syndrome.

Dr. Adi Neufeld-Cohen, of Asher’s group, in collaboration with Dr. Maria S. Robles and Prof. Matthias Mann of the Max Planck Institute of Biochemistry in Germany, looked for circadian changes in the mitochondria that, by creating peaks and dips in the cells’ energy levels, would also help regulate their day-night cycles.

The group identified and quantified hundreds of mitochondrial proteins, finding that the quantities of a whopping 40% peak once a day. Further research identified the proteins making up the mitochondrial circadian clock that regulates these activities. Surprisingly, most of the circadian proteins in the mitochondria peaked four hours into the daylight part of the cycle (in mice, which are active at night).

Among the essential proteins the researchers uncovered was a key enzyme that determines the rate of sugar use for energy production. This protein reaches its maximal amount four hours into daylight, suggesting that the mitochondria’s capacity for burning sugar peaks around this time, as well. To check, the researchers provided mitochondria with sugar and found that at around hour four, respiration and glucose utilization were indeed at their highest.

They also found that the protein responsible for the entry of fatty acids into the mitochondria only peaks at the eighteenth hour and, again, tests showed fat processing was optimal at the same time.

In mice with a genetic mutation that interferes with their overall biological clocks, the amounts of these proteins did not change over the course of the day, and the decomposition activity of fats and sugars was steady throughout.

“These findings support previous findings in our lab in which we showed that if mice eat only at night, when they are active, rather than throughout the day and night, they will eat the same amount of calories but their liver lipid levels will be 50% lower,” says Asher.

In other words, the outcome depends not only on what you eat but also on when you eat it. If we could be more aware of the timing of our cellular activities, we might be able to take advantage of various nutrients in a healthier way.


The above article is based on the press release.


  1. Thank you for the article! Fascinating.
    Wondering if we know the right times for humans to eat, be more active, etc.? For example, the peak at 4 hours of daylight is for nocturnal mice, so I’m not sure if we can extrapolate from that what the same time of day would be for us?

    • Dear Kat, that is a great question. Thank you!

      The normal feeding time for mice is night and that is how their circadian clock is wired. So yes, this study says if you extrapolate it to human beings, it should be likewise. Several scientific studies have linked disruptions of the body clock to weight gain too. But you are right, most of these studies are done on mice and we may have to wait for more studies on humans. For now, this should give us a rough idea. A good way to confirm this, would be to see if these proteins are conserved across species.. in humans too, that way we could tell with more surety.. I am sure some group must be pursuing this line of research on humans..will keep you updated if I find more info! 🙂