Eat this meal plan to cure your chronic health condition. Follow this exercise regime to balance your hormones. Is your face puffy? That’s due to cortisol; it can be rectified by completing these workout regimes.
Such messages are shared across social media platforms by health and fitness influencers, often referred to as “fit-fluencers”. These are people who use their fitness knowledge to gain an audience online, providing exercise and diet tips and tricks, or video workouts to which people can follow along.
In some cases they are people who have simply found a love for the gym or who have been on a weight-loss journey they wanted to share online; in others, they have done a course in personal training or a diploma in nutrition.
But are any of these backgrounds enough to ensure the advice they are sharing is supported by science?
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Researchers say a growing amount of health misinformation is being shared in these spheres. This was highlighted in 2022 when Stephen and David Flynn, the twins behind the Happy Pear food company, suggested mushrooms reduce the risk of breast cancer and included comments in their podcast about how antibiotics can increase depression. They later apologised for the comments, which were criticised for being misleading.
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David Robert Grimes, an assistant professor at Trinity College Dublin and medical disinformation specialist, said that often such health claims are “hitting into someone’s deepest fears and problems”.
“You have people that are very vulnerable and because we have this para-social relationship with these influencers, there’s a level of trust afforded to them that they actually don’t deserve,” he said.
We would have people coming into us because they saw a video on TikTok that if they put shampoo on their face it would clear their acne, but they break out in a big rash
— Victoria Jones
Dr Grimes said the problem was “two-fold” because these people are selling items that are not evidence-based but it also “fosters distrust” with their clinicians or medical team.
“A lot of these conditions are really complicated. They take a lot of time with specialised teams to get to the bottom of them and that’s so frustrating for people,” he said. “And then you have someone saying: ‘If you just take my vitamins, or do my training course and you’ll be cured’, you can understand the allure. But it’s exploitative and cruel.”
In recent years, the Advertising Standards Authority has cracked down on influencers, requiring them to label paid-for content and ensure that any health claims are factually correct and based on evidence.
But for posts that are not commercial in nature, the ASA has confirmed that “it is not within the remit” of its code to monitor, meaning people can largely post whatever they want.
Victoria Jones, owner of Bonnybrook pharmacy who shares women’s health information online under the name “the menopause pharmacist”, said it was important to follow people who share only “evidence-based information”.
“We would have people coming into us because they saw a video on TikTok that if they put shampoo on their face it would clear their acne, but they break out in a big rash, ” she said.

However, this trend of health disinformation is not something new, Jones added, citing the slogan popularised by English model Kate Moss – “Nothing tastes as good as skinny feels” – as an example of poor health knowledge around the disease of obesity.
“So we’ve always had negative space for health information. It used to be in paper format, but it has now moved online,” said Jones. The pages of teenage magazines, she recalled, often contained terrible advice.
Another issue that has emerged is various diets or “challenges” promoted online, such as only eating steak and eggs to lose weight, or doing juice cleanses.
Barry Murphy, research and policy officer at BodyWhys, a charity supporting people with eating disorders, said tying diet, health and weight information into a “simplified message” was “not good for anyone”.
“You can’t shortcut a lifestyle change,” he said. “It all comes down to the source, credibility and qualifications of the information or person sharing the information.”
Murphy referred to a social media challenge called “75 Hard”, which encouraged participants to fulfil a number of tasks each day for 75 days, including exercising twice daily for 45 minutes at a time, one session of which must be outside.
“But if you fall short, you have to start all over again from day one. When you build rigidity into this, that’s when there’s a problem for sure. Rigidity to me means unbendable,” he said. “And in this mindset, exercise has to be the same every day.
“Rest days are supposed to be built in; a healthy exercise regimen has rest days. But in these instances, people are encouraged to ignore body signals, and self-worth can be caught up in it, which is a concern.”
Research conducted by Dublin City University in conjunction with MyFitnessPal, an app that allows users to monitor their calorific intake, found 87 per cent of millennial and Gen Z TikTok users used the platform for nutrition and health advice rather than consulting friends, family or medical professionals.
The study, based on responses of 2,000 people across the United States, Canada, the UK and Australia to a survey by the app, found that 57 per cent of respondents were influenced by or adopt nutrition trends they have seen on the platform, with 31 per cent stating they have experienced adverse effects from them.

Sandra Wilkinson, spokeswoman for the Irish Nutrition and Dietetic Institute, said one of the problems was that a lot of people were self-proclaiming themselves as experts.
In Ireland, dietitian is a protected title, requiring registration with CORU, the regulatory body for health and social care workers, but nutritionist is not regulated meaning “people can use it very loosely”.
“There are some really qualified nutritionists who have done a lot of academic training and they work within public health arenas. There’s no way to distinguish between that or someone who has self-proclaimed they’re a nutritional expert,” said Wilkinson.
Anything that promotes that foods are good or bad, often it’s not establishing the nuance. No one food that has been regulated and complies with legislation is toxic
— Sandra Wilkinson
However, Grimes said an individual having qualifications didn’t automatically mean “what they’re selling you on social media is valid or evidence-based”.
“The mere fact that someone is qualified does not mean they have your best interests at heart. Once they’re on social media, they’re not your doctor, they’re not your trainer. They are someone looking for your attention,” he said.
One of the other issues that has emerged in recent months is a focus on ultra-processed foods. Wilkinson said this was “an area of concern” for her.
“We have very good regulation within Ireland and the EU about what is allowed be used in food and what ingredients are not. I have seen terminology be used like ‘toxic’ or quite negative terminology around foods available and there is a risk that could lead to anxiety among the general public,” she said.
“Anything that promotes that foods are good or bad, often it’s not establishing the nuance. No one food that has been regulated and complies with legislation is toxic.”
Another trend among those sharing content on social media is the promotion of macro-friendly diets – balancing protein, carbohydrates and fats, with a higher level or protein than the other two. But often the individuals promoting this diet don’t include fruit or vegetables, stating there is no need to consume these items, which is contrary to public health guidance.
“It’s detracting from the other public health messaging; our need to increase our intake of fibre [for example] – we’re far away from meeting our intakes of fruit and vegetables,” said Wilkinson. “We have excessive intake of saturated fats. They’re all very established links to the high incidence of chronic disease in Ireland.”
But with all of this in mind, how can anyone know what they can or cannot believe when it comes to nutrition or fitness advice on the internet?
You should ask yourself a number of questions, Wilkinson said, including, will the person profit commercially from you? And are relying only on their own experience?
“To make a very definitive claim about an aspect of nutrition – I would interpret that with caution,” she added.
Grimes agreed: “You shouldn’t trust anything online, not even me. You should be going to a qualified professional.”