If you delay having a meal, it also presses pause on your body clock, scientists have discovered. The finding could help cure some of the symptoms of jet lag.
The body clock is the daily rhythm of many biological processes in the body that follows a roughly 24-hour cycle. It's known to be influenced by light exposure, but a study published in Current Biology is the first to find that at least part of it is also controlled by when you eat.
In the study, a group of 10 men took part in a 13-day trial, where they were given breakfast, lunch and dinner at 5-hour intervals.
They were given breakfast half an hour after they woke up for six days. After that, they were given breakfast 5 and a half hours after they woke up.
"A 5-hour delay in meal times causes a 5-hour delay in our internal blood sugar rhythms," said study author Jonathan Johnston of the University of Surrey. "We think this is due to changes in clocks in our metabolic tissues, but not the 'master' clock in the brain."
There are many components to the body clock, and how each of them is regulated is not fully understood.
"We anticipated seeing some delays in rhythms after the late meals, but the size of the change in blood sugar rhythms was surprising," Johnston said. "It was also surprising that other metabolic rhythms, including blood insulin and triglyceride, did not change."
As a result, eating meals to coincide with your destination could help avoid jet lag. For example, if you are flying from New York to London, eating meals five hours earlier than normal the day you travel would help you adjust on arrival. Flying from London to New York, eating meals five hours later than normal would help.
Cure for 'shift work syndrome'?
Jet lag can be unpleasant, but working shifts at night is much worse for your health because of chronic disruption to the body clock. It has been linked to higher levels of stress and conditions such as diabetes, stroke, heart attack and early death.
Understanding what controls the body clock could lead to treatments to tackle some of these problems. Correct timing of meals could be part of the answer. But exactly how shift workers should adjust their meal times will need to be studied in further research.