A new study revealed that delaying a person's meal time could disrupt one of the so-called peripheral clocks in the body.
The study, published in the journal Current Biology, showed that the time a person eats breakfast, lunch and dinner could reset at least one of the peripheral clocks, without affecting the so-called "master" clock in the brain.
"A 5-hour delay in meal times causes a 5-hour delay in our internal blood sugar rhythms," said Jonathan Johnston, from the University of Surrey and one of the authors of the study, in a press release. "We think this is due to changes in clocks in our metabolic tissues, but not the 'master' clock in the brain."
For the study, the researchers recruited 10 healthy, young males. During their 13-day lab experiment, the participants were given three meals at 5-hour intervals. The researchers made sure that all meals served to the participants contain the same amount of calorie and macronutrient content.
After being used to meals given 30 minutes after they woke up, the researchers switched the participants breakfast to five hours after waking for six days. Upon completing their meal schedules, the participants underwent 37 hours of a specialized laboratory routine that removes sleep and environmental rhythms while replacing meals with hourly isocaloric snacks.
The researchers observed no changes in the participants' actigraphic sleep parameters before circadian rhythm measurement. Moreover, the delayed meal time did not affect the participants' feeling of hunger sleepiness. The master clock' biomarkers, which include rhythms of melatonin and cortisol, in addition to plasma triglycerides or clock gene expression in whole blood, were not affected by the delayed meal.
However, the researchers found that the delayed meal significantly affected the blood sugar levels. A 5-hour delay in meal time caused a delay of over 5 hours on average in the body's blood sugar rhythm. Additionally, the rhythmic expression of a gene known as PER2, which encodes a core clock, in fat tissues were also affected by the delayed meal time, having a delayed effect of about an hour.
Interestingly, delayed meal time have no effect on other metabolic rhythms, such as blood insulin and triglyceride.