After concluding his "X" Tour in 2015, the singer said on "The Breakfast Club" radio show Thursday that he "doubled in size."
"I got home and sweatpants were the only things that fit and I just thought everything had shrunk in the wash, but it hadn't," he added.
Sheeran, whose new album "Divide" is out March 3, said that he "didn't realize how much I burned on stage. I stopped touring and I just ballooned instantly."
Still, it was also one guilty pleasure that packed on the pounds: beer.
"Well, I'm back on beer now, because I'm fine, but I cut out beer for a bit and started exercising, which was quite weird," Sheeran, 25, explained.
During the interview, Sheeran also opened up about what he did during his yearlong break from social media.
The "Thinking Out Loud" singer had announced on Instagram in December 2015 that he needed a break after touring.
"I bought an iPad that has roaming on it so you can get internet on the iPad," he explained. "And then I spend the whole day having conversations with people."