Ripped. Shredded. Lean. Jacked. Hench. These are all adjectives that could be used to describe Hugh Jackman’s physique as clawed mutant, Wolverine. After a dramatic transformation from his initial appearance in X-Men (2000), Jackman’s ultra-lean, pumped up look has become the thing of legend. But it comes at a cost.

After 17 years and 1,000s of hours in the gym, after Logan, Jackman will gracefully bow out and leave the role that defined a generation of X-Men. In the build up to the film, on top of the hard work of perfecting the script and leaving his own distinct imprint on the beloved character, Jackman underwent the usual strict regime.

Jackman followed the technique of Intermittent Fasting (IF) under which, an individual has to starve for 16 hours daily and survive on a diet of boiled chicken, broccoli, and cauliflower. That’s right.

Ryan revealed that he would eat six meals a day rather than three large ones, get protein from natural, unprocessed sources, drink mainly water ad avoid all processed foods.

He would up his water intake to 3-gallons-a-day-prior-to-filming, then 36-hours prior to filming he would cease drinking water completely. That’s realy not a solid idea, but it seemed to work in his favor. Mind you, this was all on top of a 3 months of hardcore working out.

“It finishes with dehydration. Don’t do this at home; you increase the water intake to about 10 litres (3 gallons) of water a day, and then you stop about 36 hours before you shoot. But because you’ve drunk so much water, you’re peeing all the time, and then you have nothing. Then, you lose about 10 lbs of water weight,” he says on The Late Show.

To celebrate the momentous occasion of Jackman ending his diet, Fallon being Fallon, had him eat a carb-laden bowl of creamy pasta made by eminent Italian chef, Francesco Batali.

“It’s sort of unbelievable to me, what I did for 17 years. The first one, I thought you could get into shape in three weeks. The director pushed all the ‘shirt off’ scenes to the very end. You stop drinking water about 30 hours before you shoot. You lose ten pounds of water weight,” Jackman said on the show. Gasp. 30 hours without water.