New York, Nov 22 : Higher protein and salt content in our food, as well as the volume consumed, can lead to longer naps, suggests new research.

Researchers at The Scripps Research Institute in the US created a system that can measure both the sleep and feeding behaviours of individual fruit flies and discovered that, in much the same way as humans, the insects sleep for longer periods following larger meals.

Further studies also revealed that certain types of food can promote post-meal sleep.

To better understand this relationship, William Ja and his team created the Activity Recording CAFE (ARC), a system for flies that enables visual tracking of food consumption and insect motion.

Recordings of fruit flies\' behaviour from this system revealed that after eating a meal, the insect sleep more before returning to a normal state of wakefulness.

The sleep period generally lasts around 20 to 40 minutes, with flies that eat larger portions generally sleeping more.

To determine if individual nutrients could modulate post-meal sleep, the team gave the flies food consisting of protein, salt or sugar.

The study, published in the journal eLife, found that only protein and salt were effectors of post-meal sleep, suggesting that this form of sleep can indeed be regulated by specific food types.

\"The ARC provides a starting point for future studies aimed at uncovering the exact genes and circuits that enable meal size, protein and salt to drive sleep,\" Ja said.

\"As sleep is a vulnerable state for animals in nature, it will be interesting to discover why post-meal naps are necessary,\" Ja added.

Salt and protein in food lead to post-meal sleepiness