Dark secret every influencer knows goes on... but will never admit: Insiders have told me hidden shame of trick so many stars exploit. It's truly damaging: MOLLY CLAYTON - suong

Regular social media users will be all too aware that it's impossible to scroll through TikTok or Instagram without being bombarded with videos about food. Videos by 'influencers' recommending restaurants, recipe ideas or showing off what they eat in a day can rack up millions of views within hours.

Some even go further – to capitalise on social media algorithms that reward extreme or bizarre content – gorging on up to 5,000 calories in one sitting or seeking out 'the most calorific foods' they can find.

But this raises a troubling question. How do these influencers – apparently gorging on fatty, fried foods daily – maintain their stick-thin figures?

Like many other corners of the internet, there is a dark underbelly to the world of food influencing.

I can reveal that many 'food influencers' spit out their food off-camera – or simply starve themselves before and after filming.

'People don't understand that a lot of influencers just taste the food and never actually eat it all,' one source said.

'That's how they don't gain weight. They just bite and spit it out. If you look closely, many of them edit the videos so that you never see them swallow.'

Since the launch of TikTok, videos with the hashtag 'mukbang' – an online phenomenon that began in Korea, where a person films themselves eating – have skyrocketed to more than six million.

The internet is now flooded with videos of super-fit influencers apparently stuffing their faces – and experts warn it is warping the way people eat.

A quick search on TikTok for 'What I eat in a day' produces hundreds of videos of young, slim women dressed in super-tight gym clothing filming the food they eat over 24 hours.

TikTok itself even flashes up a warning: 'If you or someone you know has questions about body image, food or exercise – it is important to know that help is out there and you are not alone. If you feel comfortable, you can confide in someone you trust or check out the resources below.'

One industry source tells me that many of these influencers shoot weeks' worth of content in a single day – then fast for days afterwards and work out vigorously.

Some even take appetite stimulants (like antidepressants or steroids) to make them hungrier for a few hours on filming days, my source tells me. Others will pretend to eat on camera and then spit each mouthful into a bin once filming stops.

'Food influencers only eat a small portion of everything and eat very light and clean on 'off' days,' they say. 'Some also don't actually swallow the food they're eating, they'll take a bite and then cut the cameras so they can spit it out.'

Take New York food influencer Tram Tran – aka 'babydumplingg' – who boasts 2.1 million followers on TikTok. She has been accused by her followers of not swallowing any of the food she claims she eats.

In a recent video, the svelte Tran shows what she eats on a regular 'day in the life'. She claims to eat 65 pieces of sushi for breakfast, a Sprite, a BLT sandwich, pasta, ice cream, a burrito, a roll with sausage, egg and cheese, two slices of pizza and a Chinese takeaway.

Another video shows her eating 10lbs of food for breakfast – the equivalent of a sack of potatoes.

Fans have now begun to question how she's able to eat so much without gaining weight.

'Why don't you ever show yourself swallowing any of the food?' one comment asks.

'This is about 7,000 calories: how are you the size you are?' asks another.

In January, TikTok users in the United States faced an unexpected blackout as the app was temporarily shut down due a threatened 'ban' on the Chinese-owned app. Terrified that their careers would soon be destroyed, TikTokers started a trend in which they shared 'confessions' about themselves.

Going along with the trend, Tran released a video admitting to not eating all of the food she says she does. Yet once TikTok revealed it would be resuming its services in the US, she claims the video was a 'joke'.

Another content creator Tasmin Dhaliwal, who has 1.5million followers on TikTok, said in a video: 'Some of your favourite influencers buy a box of cookies, eat them, spit them out, and get paid for the views from that video.'

The influencer, who usually posts videos of herself eating junk food, then showed a plate of fruit and vegetables. She said: 'This is what I eat on a day where I am not filming.

'I do swallow all of my food, but a lot of influencers don't,' she said.

'I work out five days a week and almost every day I go to the gym. I eat like this, 80 per cent of the time. And the other 20 per cent I will post a video of me eating like s***.

'So many influencers have told me they spit out their food. They do anything to make money. Stay vigilant.'

Indeed, there is plenty of money to be made in food 'content creation'.

But experts are concerned that junk foods in particular are being 'normalised' online – encouraging viewers to eat an unhealthy diet themselves. Studies have found that social media strongly influences teenagers and their eating habits.

An insider says: 'People need to know it's all about what will get the most views. There's such a high chance that after eating these big meals, they're not eating before or multiple days after that.

'It's a very toxic industry.'