While he says he's been given a clean bill of health by the surgeon, Liam had to reassess his strict diet and alter his vegetable intake.
"Once you get one kidney stone, you have a 50 per cent chance of getting another one if you continue eating the way you were eating," he explained.
"Well, my particular kidney stone was a calciumoxalate kidney stone. It forms from having too much oxalate in your diet. Oxalates are really high in a lot of vegetables, specifically spinach, almonds, beetroot, potatoes. Every morning, I was having five handfuls of spinach and then almond milk, almond butter, and also some vegan protein in a smoothie. And that was what I considered super healthy. So I had to completely rethink what I was putting in my body."
During his chat with Men's Health, Liam also revealed how he coped with the fallout from his eight-month-long marriage to Miley, admitting he's been working hard to regain balance in his life.
"This last six months, honestly, for keeping my head level and just staying balanced, I’d say exercise has been big for me,” said the actor, who is currently training intensely and getting into shape for his new flick, Most Dangerous Game.
Then, when asked if he's in a "rebuilding" phase of his life, he said, "yeah, that's a good way to put it."
His subtle reference to the 'Slide Away' singer comes two weeks after an insider revealed Liam's new girlfriend, Gabriella Brooks, made him realise he's never felt better, safe or more comfortable in a relationship.
"He feels more at home with Gabriella than he did with Miley [Cyrus]," a source told US Weekly. "He feels like he can be his complete self without any drama."
The insider continued: "Gabriella helped Liam boost his confidence and played an encouraging role in his life after his split with Miley. They are very happy together and it's comfortable and easy."
But what does Miley think of his new romance?
"Miley is not asking their mutual friends about Liam’s new relationship. She doesn’t want to make anyone uncomfortable. She is not checking in on Liam" a source close to the pop sensation turned Black Mirror actress told Hollywood life.
"When they first broke up, a lot of their closest friends were in disbelief and thought they’d get back together. They were always fighting and breaking up and making up and everyone thought they’d get past this, but it got too deep.
"Liam just realised he wanted a different kind of wife, one who was more traditional and reserved, and his family really helped him take the step in divorce. He’s happier, but he does miss Miley. The divorce really divided some of their close friends."
Thankfully, Miley has also moved on from all the drama and recently celebrated her six month anniversary with Cody Simpson while in isolation!