Overloading on holiday treats can have the same effect on your system as being jet-lagged, say researchers.

Researchers from the University of California, San Francisco said that a day of eating rich food and staying up late can upset the balance of your “food clock”, which they describe as a collection of interacting genes and molecules that keep the human body on a metabolic even keel.

In a series of tests with lab mice, the researchers found that disruptions in regular eating and sleeping cycles especially affect mice lacking a protein called PKC, which could provide clues into the molecular basis of obesity and diabetes, the New York Daily News reported.

Mice lacking PKC weren’t able to bounce back as quickly as mice with the protein after disruptions to their 24-hour cycle. The researchers said the findings could explain why night owls are more likely to be obese than early risers.