A social media star who undertook a two week fast has revealed the brutal impact the challenge had on his body. 

Justin Dorff has built a following of 24,000 subscribers on YouTube by tackling a variety of elaborate health and fitness challenges. These include trying out longevity expert Bryan Johnson’s $2 million anti-ageing regimen and following extreme diets such as consuming only eggs or butter for a full 72 hours.

But the 42-year-old health coach embarked on a new feat, drinking only water and not consuming food for seven days. 

The influencer and entrepreneur, based in Pennsylvania, was already in good shape, weighing approximately 148.1 pounds (67.2 kg) with a waist measurement of 32 inches (81.3 cm).

Now, in a recent YouTube video, which was been viewed almost 100,000 times, he told how the challenge shockingly had a ‘God mode’ effect on his body.

After suffering four ‘fantastically rough’ days ‘feeling hollow’, on the fifth day he awoke with ‘tons of energy’ and ‘crushed’ his workouts. 

The week-long feat, instead, gave him the ‘opportunity to reset the body, mind, and spirit’. 

Although numerous studies have supported intermittent fasting—which became popular in the early 2010s—as effective, experts continue to debate its efficacy and the potential long-term effects on health.

Justin Dorff’s YouTube popularity can also be attributed to showcasing high-profile challenges, like the $2 million anti-ageing routine of longevity expert Bryan Johnson, and unique diet tests over a short span.

Hollywood stars, including Jennifer Aniston, Chris Pratt, and Kourtney Kardashian, have embraced fasting trends since they gained traction in the early 2010s. However, despite plenty of research suggesting it works, experts are still divided on its success and possible health implications over time.

Some claim that people who fast often eat a substantial amount in one sitting, potentially negating calorie reduction, a conventional method for weight loss.

They even warn that it may raise the risk of strokes, heart attacks or early death. 

Scientists have also urged caution over fasts that last more than a day because of their ‘short-lived’ effectiveness, advising that they could trigger chronic health issues like digestive conditions. 

Mr Dorff said: ‘For the past two months, I’ve been feeling tired. I’ve got nagging injuries. I’ve got this low-level stress. I crave junk food. I feel kind of sad and not really myself.

To combat this, he said he would be tracking his mood, ‘cravings, hunger, and energy’ throughout the seven day fast, which he dubbed the Great Reset.

The first 20 hours were ‘fairly normal’, while ‘nothing really dramatic’ occurred, he added.

He had ‘no real cravings not much hunger, plenty of energy.’ 

During this time, it is believed that the body burns through its stored glucose called glycogen and once that runs out, you start burning body fat. 

By the end of the challenge, he had lost over 10lbs and 10.5in around his waist, while his cravings for junk food disappeared

It was only on day two that the challenge became far more difficult. 

‘I felt tired, foggy headed, kind of nauseated,’ he said. 

In an effort to cope with such symptoms, he took multivitamin tablets, electrolyte capsules and salt water—specifically to combat the headaches. 

‘But my motivation and energy quickly disappeared,’ he noted.

‘My goal was to reset my mind and my body but I feel rundown, physically and mentally. I’m trying to distract myself and keep busy until bedtime.’ 

Days three and four were also ‘fantastically rough’.

‘I woke up feeling hollow, like someone scooped out my insides, and I’m just withering away. Also, my hands and feet were cold and white,’ Mr Dorff said. 

‘I drank an absurd amount of salt water, and spent an hour just staring out the window.

It comes as an illuminating video posted online in May garnered thousands of views for its alarming display of exactly what happens to the body—hour by hour—when fasting 

‘The evenings were brutal, hunger and cravings were at their highest, energy and mood were at their lowest.’

On day five, however, Mr Dorff told how ‘everything changed overnight’, switching from ‘zombie to God mode’. 

By day six he had lost over seven lbs, dropping from 148.1lbs (67.2kg) to 139.6lbs (63.3kg). 

‘But more important than the physical results was how I felt,’ he added.  

‘I wasn’t white knuckling it through hunger and cravings. I had tons of energy and crushed my workouts. I could focus, waking up however was difficult.’

By the end of the challenge, he had lost over 10lbs and 10.5in around his waist, while his cravings for junk food disappeared. 

It comes as an illuminating video posted online in May garnered thousands of views for its alarming display of exactly what happens to the body—hour by hour—when fasting. 

The four-minute gut-wrenching simulation claimed the body stops digesting food after just four hours, entering what is known as the catabolic phase—when muscle and fat is used for energy.

By 12 hours, it has hit a ‘fasted state’ depleted of blood sugar. Here, the liver begins to break down stored fat into fatty acids called ketones to use as fuel.

But ketones can be dangerous—high levels of them in the blood can lead to a condition called ketoacidosis, when blood becomes too acidic. If not treated promptly it can be life-threatening.

Studies have also found that prolonged exposure to ketones can be detrimental to the heart, increasing the risk of heart attacks and strokes.

Fasting up to 16 hours can then stimulate autophagy— where cells break down and remove damaged or unnecessary components like old proteins—it is claimed. 

Research has long warned, however, that excessive or prolonged autophagy can lead to cell death, potentially harming organs.