If the excesses of holiday eating have sent your system into butter-slathered, alcohol-soaked overload, you are not alone. People with jet-lag, those who work graveyard and 24 hour shifts and even late-night snackers know just how you feel.
Turns out that all these activities upset the body’s “food clock” – a collection of interacting genes and molecules which keep the human body on a metabolically even keel. Look behind the face of a mechanical clock and you will see a dizzying array of cogs, flywheels, counterbalances and other moving parts.
Biological clocks are equally complex, composed of multiple interacting genes that turn on or off in an orchestrated way to keep time during the day. In most organisms, biological clockworks are governed by a master clock, referred to as the ‘circadian oscillator,’ which keeps track of time and coordinates our biological processes with the rhythm of a 24-hour cycle of day and night.
Scientists also know that in addition to the master clock, our bodies have other clocks operating in parallel throughout the day. One of these is the food clock, which is not tied to one specific spot in the brain but rather multiple sites throughout the body. The food clock is there to help our bodies make the most of our nutritional intake. It controls genes that help in everything from the absorption of nutrients to their dispersal through the bloodstream. It’s also designed to anticipate our eating patterns. Even before a meal, our bodies begin to turn on some of these genes and turn off others, preparing for the burst of sustenance – which is why we feel the pangs of hunger just before our lunch hour.
And while scientists have known that the food clock can be reset over time if a person changes their eating patterns, very little was known about how the food clock works on a genetic level.
Until now! A new study by researchers at the University of California, San Francisco published in Proceedings of the National Academy of Sciences, is helping to reveal how this clock works on a molecular level. The study showed that normal laboratory mice given food only during their regular sleeping hours will adjust their food clock over time and begin to wake up from their slumber, and run around in anticipation of their new mealtime. But mice lacking a certain gene (PKCγ) are not able to respond to changes in their meal time and instead sleep right through it.
The work has implications for understanding diabetes, obesity and other metabolic syndromes because a desynchronized food clock may serve as part of the pathology underlying these disorders.
“It may also help explain why night owls are more likely to be obese than morning larks,” says Louis Ptacek, MD, Distinguished Professor of Neurology at UCSF. “Understanding the molecular mechanism of how eating at the “wrong” time of the day desynchronizes the clocks in our body can facilitate the development of better treatments for disorders associated with night-eating syndrome, shift work and jet lag.”