Jared Leto is known for taking his body to extreme limits to prepare for acting roles.
Normally lean and fit, he overate to put on slabs of fat for the 2007 film Chapter 27 and got down to 116 pounds for his award-winning role in 2013's Dallas Buyers Club.
In normal acting roles or when spending time with his Thirty Seconds to Mars band, Leto is able to stay healthy by living an active lifestyle, getting plenty of sleep, eating a clean vegan diet, and avoiding alcohol.
Leto has avoided putting on extra fat for roles, after having health issues from his role in Chapter 27. He now keeps a lean build, except for putting on muscle for when he needs to fight Batman, like in 2016's Suicide Squad.
The Jared Leto workout routine
Leto keeps healthy by staying active, with things like hiking, cycling, and yoga workouts. When the role requires it, he does bulk up. For his role as the Joker in the DC Films Universe, he had to bulk up to be able to take on Batman, which he shared in an Instagram post.
In most of comic book history, the Joker has never had a bulky look. While he isn't a physical match for Batman, Leto bulking up allows him to look like he can at least hold his own in a fight with the caped crusader.
The Jared Leto diet plan
When he isn't going to extremes to prepare for a role, Leto follows a vegan diet, which avoids animal foods and any of their by-products. This obviously makes the focus of his diet to be whole nutritious foods like fruits and vegetables.
Leto shared how a commitment to eating clean foods has helped to keep him healthy despite a busy schedule, according to an article on Examiner. Leto also avoids drinking alcohol.
I'm pretty healthy so I think that helps a lot. I've been that way for a long time. Twenty solid years of eating vegetarian/vegan and taking care of myself. That probably helps the preservation process.
His weight gain diet for Chapter 27 consisted of plenty of junk food, such as ice cream mixed with soy sauce and olive oil. The extra weight contributed to Leto getting gout, which put him in a wheelchair. After filming, Leto followed a liquid fast diet to drop weight quickly, which helped him drop 20 pounds in the first 10 days.
Leto felt that gaining that much weight for a role was unhealthy and that he would never do it again, saying "It took me about a year to get back to a place that I felt semi-normal. I don't know that I'll ever be back to the place I was physically. I'd never do it again; it definitely gave me some problems".