ET sat down with the 30-year-old singer to talk about his new music, where he also discussed his time in at the facility and his healthy 45-pound weight gain.
"Well, I struggled from an eating disorder, so I had seven ulcers," Carter notes about his former physique. "I was, like, 115 pounds, super malnourished."
"It was tough, you know, it was tough a bit on myself, but the Alo House where I went was incredible," he says, praising the facility in Malibu, California. "They helped figure it out for me what was going on with me, and there are other things going on, like, I suffer from PTSD. I have a lot of trauma from my past and a lot of loss, so that's something I have to deal with on a daily basis."
Carter says he was able to gain the weight in less than 50 days by going through detox.
"I did detox and through that detox, I gained, like, two pounds every day," he reveals. "Twenty-eight percent of body weight I gained. ... I took a break, and figured out what was going on in my mind, and the things that were really festering up and bothering me. I'm still figuring those things out."
Of course, Carter is happy with his noticeable progress so far.
"I had body dysmorphia too, because I was so skinny," he shares. "So, I would use those face-tuning apps and things like that to just to try to like make myself look bigger. I finally looked at these two [before and after] pictures and it was crazy the amount of weight [I gained]. I can even flex my abs right now."
Still, the singer is honest about what substances he continues to partake in.
"Of course, I am an addict, I don't have to feel like it, I am," Carter says, before explaining that he was truthful at the facility about his habits.
"I mean, I told everybody where I was at, I was like, 'You know, when I finish here, I probably will be smoking weed,' and that is just something that is a part of my ... it is my ritual kind of, it's not just something you use to smoke, it is kind of like how the Marleys did it. Like, I am in love with the Marleys."
"They said it was like their spiritual touch and that's how they found their spiritual self, so that is kind of how I use it," he continues.
As for alcohol, Carter says he has a glass of wine occasionally, and also says he's taking medication for PTSD. Carter stresses that he takes full responsibility for his issues.
"No, it's not a product of my environment, that is bullsh**," he says of the problems he's experienced. "Naw, it's up to the person."
"What does sobriety mean to me? I will have to say staying off of certain things, like, staying in what I am doing right now," he notes.
These days, Carter is all about his new music. Earlier this month, he released his new song, "Don't Say Goodbye," and he's also releasing an upcoming album titled LøVë in February.
"For me, I just need to, you know, stay focused and get back onstage, because you've never even seen me onstage," he teases. "I will blow your mind."
"I'm a big fan of, I don't know, urban culture," he also says of his new music. "I have a lot of urban in me. ... There's shades of EDM, dub step and dub trap, so I call it dub trap because of the kind of snares and instrumentation that I use to make these beats are trap music."
"I'm telling you, it is what I grew up on," he adds with a smile. "Come on, I'm a white boy riding around in my trucks when I'm 15 and 16. You don't think I wasn't listening to Juvenile and Trick Daddy?"