We all love indulging in a bit of fast food every now and then, but some pretty disgusting things can go on behind the counter that we don't know about.
Anonymous employees from fast food restaurants have divulged the kitchen secrets on Reddit, and you'll certainly think twice before chomping down on a burger.
The employees have warned what foods to steer clear of and McDonald's and KFC were seriously criticised by employees.
So here is what you should avoid next time you're ordering.
The gravy drizzled on the KFC mashed potato has always been a crowd favourite, but apparently it may not be what we think.
Employees have warned us to steer clear of the gravy, because it's made with the dregs from the bottom of the fryer.
"I recommend that you don't consume the KFC gravy," a former cook said.
"It is primarily made of the filthy oil that stores up on the bottom of the cookers over the day and is then served to customers the next day.
"Also the 'potato' in potato and gravy is literally just flour, there is no potato at all whatsoever."
So have we been living a lie this whole time?
A former employee at KFC in Australia also said to avoid the gravy.
"It's kind of technically made how gravy should be, leftover chicken and stuff, but it's actually the bottom of the fryers cleaned out once a week, then frozen," the former employee said.
"Instead of throwing out all the chunks that drop into the fryer's reservoir over time, they make it gravy.
"The reservoirs are 90 per cent oil, the rest flour, and a few pieces of well burnt chicken."
When contacted by news.com.au, KFC replied, "KFC Australia is passionate about serving our customers freshly prepared, great tasting food. Our gravy is made in our restaurants using a traditional method, which ensures an authentic and unique flavour."
You may try to go for the healthy option at fast food restaurants, but a McDonald's employee warned against ordering the side salad.
"The side salads are an item that rarely moves. So re-stickering them is a daily routine," the employee said.
It's not the most popular item on the McDonald's menu anyway, but a number of employees recommend avoiding it.
A current McDonald's employee said the fish fillet usually sat on a tray for at least an hour.
Another employee agreed and said the fish sat there for hours and became "absolutely disgusting".
"Do no order a fish fillet unless you ask for a fresh one," the employee suggested.
"This goes for any fast food place, never order anything so close to closing time, there's a good chance it won't be fresh."
How bad can ice be? Apparently, pretty gross.
Fast food workers said customers should order soft drinks without the ice because the machines aren't always kept clean.
"Can't tell you the number of ice machines I've seen with mould and dead flies in the bottom," a McDonald's employee said.
Another fast food worker also warned people to stay away from ice cubes.
"Those machines contain more mould and slime than you want to guess at," the employee said.
Everybody loves a bit of chocolate with their ice cream, but apparently it's not the best idea.
A former McDonald's employee said the chocolate was left out all day.
"The top layer will congeal and they just mix that s*** back up and still use it," the former worker said.
"Not to mention, at the McDonald's I worked at, we sprayed the trays off next to the chocolate, so God knows how much chemical gets into it."
A former Australian McDonald's employee shared a couple of hacks on how to get the best quality food possible.
The worker recommended not ordering new and limited edition menu items.
"Nobody knows how the make it and I can guarantee you it will be made wrong or missing ingredients," the former employee said.
Customers were also given advice on what to do if they wanted fries or burger patties cooked fresh.
"A common myth is that asking for extra salt on fries or seasoning on meat will get it cooked fresh. Usually the person just gets an old patty and sprinkles more on it, same with fries," the former worker said.
"If you want fresh meat you have two options. Ask for it fresh directly or ask for no salt. Tell the cashier you're allergic or something and they will communicate it to the kitchen."
The former employee also shared tips on how to get free food if you leave your wallet at home.
"You can ring a store half an hour before you go in and make up a complaint. Say something along the lines of 'I just got a Big Mac earlier and the lettuce was brown and I had to throw it out'. Just be creative. They aren't going to check the cameras or ask for a receipt unless you either ask for (a lot) of food or say something that seriously violates health code," the former worker said.
"They will generally offer a replacement, if they don't, just ask for one."
Also, want to get more ice cream for less money? Of course you do.
The former employee said instead of ordering a Sundae, customers could order two cones, without the cone.
"It only costs $1 and will have more ice cream. It gets delivered on Sundae lids," the former worker said.
- McDonald's Australia has been contacted for comment