People left disgusted as 'gross' video demonstrates exactly how flies eat food

People have been left disgusted as a 'gross' video demonstrated exactly how flies eat their, or more realistically, our food - and well, you can't blame them.

We've all been there, wafting away pesky flies too rude to wait for us to finish our food before wanting to dine themselves, and we thought we were doing so because of how dirty they are - well, we were wrong.

Well, we weren't exactly wrong because flies can leave behind thousands of germs that can cause serious illnesses, like food poisoning, diarrhoea and even meningitis and more.

But after watching a short video on it, next time we're caught swatting a fly it won't be because of its germs - it will be what it does to our food!

A house fly digging into what appears to be a donut. (Getty Images)

So how do they actually eat?

First, we would need to look at the biology of the fly; its mouth is made up of what could be described as two sponge pads and a straw - kind of like a vacuum.

Grooving on their lips allow liquid to flow through its two sponge-like pads, which are attached to its lower lip. However, because they have no teeth it means they must somehow dissolve your burger, chicken, popcorn, or whatever else their grubby paws get on, into a liquid.

So how do you turn solids into liquid? Well in the case of house flies you simply regurgitate enzyme-rich saliva you store in your stomach and spit on it and convert it into particles measuring no more than 0.45 millimeters.

Or to put it more simply: if you catch a fly digging into your food then they are puking their guts up before enjoying their mushy, liquid feast.

One commenter on Reddit was shook by the revelation and warned those not to watch it, saying: "I want to let you all know since I have last seen this clip 3 months ago till now, my life has not been the same.

"I now hate flies and will never eat food that has been touched by a fly again. If somehow you have not seen this still, do not watch it!"

While someone else added: "Sooo...how fast will they puke on my food from the landing?"

Replying, another joked: "They spray as they land like a mofo [sic] Apache raining bullets down."

Houseflies will plant their eggs in food and maggots can hatch in as few as 24 hours. (Getty Images)

But it doesn't stop there, because houseflies actually have tastebuds on their feet meaning they have already enjoyed a taste of your meal even if they didn't get a chance to dine.

Given enough time, if it suits they will even lay their eggs in your dinner - eggs that turn into maggots that can hatch in as few as 24 hours.

Needless to say, you definitely shouldn't hesitate to swat a fly away from your dinner in future!