The Melbourne scientists behind the low FODMAP diet, which brings relief to millions of people with irritable bowel syndrome, fear they are losing control of their eating plan to Instagram influencers and celebrities using it for other, scientifically-unproven goals.

Associate Professor Jane Muir and Professor Peter Gibson from Monash University carefully developed and tested the plan, which has quietly become one of Australia's most successful science exports in the past few years.

Dr Jane Muir and Professor Peter Gibson from Melbourne's Monash University invented the low FODMAP diet. Joe Armao

FODMAPs are sugars in foods like onion, garlic, honey, dairy and wheat. In people with irritable bowel syndrome, they can cause bloating and pain. The low FODMAP diet reduces those sugars, which is proven to cut the symptoms of IBS.

But online, their diet has warped into something very strange.

One website warns FODMAPs are "dietary villains" that cause acne breakouts. Their solution? Yoghurt, cheese and sauerkraut juice to rebuild your gut bacteria so you can eat them.

Some bodybuilders are promoting their own low FODMAP diets, which can supposedly help them pack on huge amounts of muscle.

The actress Blake Lively reportedly used a low FODMAP meal service to help lose her baby weight. AP

Gossip Girl actress Blake Lively also reportedly used a low FODMAP meal service to lose her baby weight.

One social media user has taken to testing food on his rabbit, insisting that if the animal eats it, that means it’s low FODMAP.

“He had a whole list,” said Dr Muir, shaking her head. “It’s a real mess.”

“There is all this inaccurate information out there. It’s extraordinary. We have spawned an industry."

Monash's official FODMAP app has been downloaded in more than 130 countries. There are now more users in the United States than Australia. The program is earning the university millions of dollars, all of which go back into diet research.

The diet, says Professor John Furness, one of Australia’s leading digestive scientists, is “a major advance ... a major Australian science contribution”.

Before Gibson and Muir invented the diet in 2002, there were few effective treatments for irritable bowel disease. The condition affects between 10 and 15 per cent of Australians, but we did not have a strong handle on what caused it, or how to diagnose it.

Scientists knew that diets excluding foods such as onion, garlic, baked beans, lactose, fructose or gluten could help some people with IBS, but not everyone.

Professor Gibson and Dr Muir changed all that with an idea that seems so simple you wonder why nobody thought of it before.

“All these things do similar things in the gut,” says Professor Gibson. “So why don’t we add them all together?”

It seems to work. Patients with IBS using the diet see their symptoms improve by about 50 per cent on average, a 2016 review found, although long-term effects remain unclear.

FODMAP stands for Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols.

This group of sugars is not well digested by the gut, so reach the small intestine largely intact. Bacteria feed on them, generating gas, which causes the walls of the intestine to stretch.

FODMAPs are in just about everything. But luckily – and for reasons we still don’t really understand – most people only have problems with a few FODMAPs.

The current form of the diet reduces all FODMAPs and then slowly adds them back in, one at a time, to find the real culprits.

While its benefits are clear for IBS sufferers, it seems to have suffered the fate of all diets in becoming a fad.

Monash's FODMAP diet, intended to ease the symptoms of Irritable Bowel Syndrome, has been adopted by millions of people worldwide. Supplied

“We quickly gathered this could turn into an epidemic like gluten-free, which we did not want,” says Dr Muir.

Most scientists move on after they finish a project. But fearing what would happen to their diet if they did not fight for it, Dr Muir and Professor Gibson decided to stick around.

Money from the official FODMAP app has allowed them to assemble a large team, which now spends much of its time fighting disinformation on social media, or battling fake FODMAP apps that contain bogus food databases.

“To keep on top of it is massive. But we are trying our best to make sure we get good information out there, so we are credible sources of reliable info," says Dr Muir.

"That’s all we can do."