Study explains how trend of protein-heavy meals and snacks is inducing more ‘food comas’

It’s a well-known phenomenon, the post-lunch slump.

At around 2.30pm, many office workers report feeling sluggish, tired, and unmotivated.

And now, in a first-of-its-kind study, scientists have pinpointed the culprits: protein and salt.

According to scientists at The Scripps Research Institute (TSRI), the body appears to shut off other functions to maximize gut absorption of these vital nutrients. 

The more you’ve consumed, the more deep a ‘food coma’ you will experience.  

It is an interesting finding amid a surge in popularity for protein in snack bars, smoothies, salads, and sandwiches on the high street.

In a first-of-its-kind study, scientists pinpointed the culprits for food comas: protein and salt
In a first-of-its-kind study, scientists pinpointed the culprits for food comas: protein and salt

In a first-of-its-kind study, scientists pinpointed the culprits for food comas: protein and salt

‘The protein link to post-meal sleep has been mostly anecdotal, too, so to have it turn up in the study was remarkable,’ Dr William Ja, who led the study, said.

Until recently, there has been little more than anecdotal evidence to suggest that ‘food coma’ is an actual physical condition – and the scientific evidence that does exist is unable to explain why some people fall asleep immediately after eating, some later and some not at all.

‘Different foods play different roles in mammalian physiology, but there have been very few studies on the immediate effects of eating on sleep,’ said Dr William Ja in the online journal eLife.

Ja and his colleagues used fruit flies as a model.

Fruit flies have a well-documented sleep-metabolism system – they suppress sleep or increase locomotion when starved.

The scientists created a small plastic chamber that allowed them to monitor the fly before and after feeding.

As expected, they found that after a meal, flies increased sleep for a short period before returning to a normal state of wakefulness.

Flies that ate more, slept more.

And to their astonishment, their study confirmed the widely-received – but untested – theory that protein is a key factor contributing to food comas. 

They found that protein, salt and the amount eaten promoted sleep.

Conversely, sugar did not.

‘In humans, high sugar consumption provides a quick boost to blood glucose followed by a crash, so its effect on sleep might only be observed beyond the 20 to 40 minute food coma window,’ Dr Ja said.

Dr Ja insists the findings are applicable to humans. 

Previous studies have shown that electrical activity increases in the brain according to meal size and during certain stages of sleep.

Humans also get sleepy after consuming a lot of salt. 

‘Using an animal model, we’ve learned there is something to the food coma effect, and we can now start to study the direct relationship between food and sleep in earnest,’ Dr Ja said. 

‘This behavior seems conserved across species, so it must be valuable to animals for some reason.’