Fitness experts have warned that the viral 75 Hard fitness challenge is ‘a recipe for burnout an injury’, after TV presenter Paddy McGuinness revealed a dramatic transformation following the regime.
The 75 Hard challenge, a military-style programme combining exercise, diet and rigid self-discipline, is trending once again as thousands embark on New Year’s resolutions to get fit.
McGuinness, 52, is the latest celebrity to jump on the bandwagon, revealing his dramatic transformation and chiselled abdominal muscles over the weekend.
But experts warn that while some people may see impressive results, the programme is not suitable for everyone, requiring strict adherence to a set of seemingly arbitrary rules.
Launched in 2019 by American entrepreneur – and self-styled ‘certified dominator’ – Andy Frisella, the 75-day high-intensity regime claims to offer a holistic approach to health and often results in significant weight loss.
There are five crucial elements to the programme: following a non-specified but ‘clean’ and challenging diet with no cheat days; drinking at least 3.79 litres of water a day; completing two 45-minute workouts daily – one of which must be outdoors; reading 10 pages of a non-fiction book; and taking daily progress pictures.
Crucially, if you compromise on any one of these rules – for example, by reading nine pages instead of 10 – you must start again from day one.
Alcohol is strictly prohibited, as are ‘cheat meals’, and participants are not supposed to modify the programme to make it easier – regardless of their baseline fitness.
Paddy McGuinness showed off his ripped abs on social media after his incredible weight loss transformation
The TV presenter, 52, who has taken on a 75-day fitness challenge, 75 Hard, proudly displayed his results in a before-and-after photo
For the TV presenter, this meant kicking a two-month binge-eating habit that saw him gorging on cakes and biscuits, washed down with beer.
McGuinness proudly showed off his ripped abs on social media in a before-and-after photo, describing the results as ‘amazing’.
Looking back, he said: ‘It really is incredible what can be achieved in such a short period of time… if you’ve got the willpower.’
He admitted the challenge might not be for everyone, but added: ‘If you’ve got even an ounce of willpower, why not give something a whirl?’
That mindset closely mirrors Frisella’s own philosophy. ‘In life, conditions are never going to be perfect,’ he has said. ‘You are always going to have to do things you don’t want to do.’
Those who successfully complete the challenge are promised they will be in the best physical shape of their lives, alongside improved mental wellbeing.
However, despite building an army of health-conscious supporters who rave about the programme online, experts say there are several serious downsides when it comes to fitness, transformation and long-term self-improvement.
One issue is the relatively short duration of the challenge, which can be completed in less than two and a half months.
Paddy said that he couldn’t believe ‘how much he let himself go’ after over indulging on beer and sugary snacks (pictured in March)
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While most people will see some results if they adhere to all of the constraints, experts warn there is only so much the body can achieve in a fixed time frame – and results cannot always be ‘supercharged’.
There is also a strong risk that once the challenge ends, people revert to old habits as work, social and family life inevitably take over.
McGuinness himself admitted he ‘couldn’t believe how much he’d let himself go’ after over-indulging on beer and sugary snacks earlier this year.
According to Emma McCaffrey, a personal trainer and founder of Move With Emma, beginners and middle-aged women may be particularly vulnerable to the downsides of the 75 Hard.
‘While 75 Hard is marketed as a mental toughness challenge, for most women – especially those over 40 – it is a recipe for burnout and injury,’ she said.
‘True, sustainable transformation doesn’t come from a 75-day sprint. It comes from progressive overload on your own terms, in a way that is nourishing and realistic for your life.’
McCaffrey warns that the regime allows for zero recovery time, increasing the risk of physical breakdown.
‘Two 45-minute workouts a day with no rest leads to systemic inflammation and overuse injuries,’ she said.
75 Hard is all the rage among influencers, but experts have warned against the potential harms – and Ireland-based Aoife Clauson (pictured) said she ended up in hospital during the regime
‘For beginners, the musculoskeletal system hasn’t adapted to handle such high volume. Without recovery days, the body cannot repair the micro-tears in muscle tissue, leading to chronic fatigue, tendonitis or stress fractures rather than strength.’
She also highlighted the hormonal impact. ‘For women over 40, our physiology is more sensitive to stress. Extreme caloric restriction combined with overtraining can spike cortisol.
‘High cortisol levels are counterproductive – they lead to muscle wastage, sleep disruption and creeping weight gain, particularly around the midsection. We should be training to lower our stress response, not heighten it.’
The challenge has also raised concerns around hydration. Personal trainer and midlife weight-loss coach Rachael Sacerdoti warned that forcing yourself to drink more than 3.5 litres of water a day is not appropriate for everyone.
‘Drinking a gallon of water daily might sound healthy, but it can lead to hospitalisation for severe sodium deficiency – a condition known as hyponatraemia, or water toxicity,’ she said.
‘In rare cases it can cause seizures, coma or even death. How much water you need depends on body size, activity level and climate.’
Ireland-based influencer Aoife Clauson said she ended up in hospital while attempting the programme last year, sharing a TikTok that read: ‘This is your sign not to do 75 Hard. Ended up in ED on day three.’
Elsewhere, Australian TikToker Mikayla Ann said she was forced to stop the challenge on day 18 after falling ill.
‘I’m currently sick as a dog in bed,’ she said at the time. ‘I physically can’t do anything.’
Sacerdoti also warned of the risk of disordered eating, describing the ‘no cheat meals’ rule as a breeding ground for orthorexia – an unhealthy obsession with ‘clean’ eating.
‘Eliminating flexibility around food can foster a damaging relationship with eating,’ she said. ‘Would you want your children following this approach? If not, why would you?’
Eating-disorder specialists have previously warned that taking daily progress photos can fuel harmful self-criticism for some people.
Ultimately, experts agree the biggest issue is sustainability.
‘What happens on day 76?’ Sacerdoti said. ‘Progress made through extreme restriction and overtraining is often undone because no sustainable habits have been built.
‘Instead, people white-knuckle their way through 75 days of misery. The restart rule creates toxic pressure and reinforces an all-or-nothing mindset – the very thing that keeps people trapped in the yo-yo cycle.’
