Ed Sheeran shed four stone after trolls branded him "fat".
The 'Perfect' hitmaker slimmed down from 16 stone to 12 stone after people pointed out he had piled on a few pounds, but he believes they only did so because they were feeling "insecure" themselves.
He said: "I never had insecurities and people pointed them out - your brain starts thinking about them.
"It all stems from other people's insecurities. So many people have things they're insecure about so it makes them feel better to point out someone else's.
"Because half the people that would point out that I'm fat are probably fat themselves."
However, Ed admits he used to eat too much and didn't exercise enough, leading to his pals nicknaming him "Two Dinners Teddy".
He said: "My problem was I'd go to the pub, have bangers and mash, a pie, maybe a pudding and then loads of pints. And then not exercise.
"My friends used to call me Two Dinners Teddy. On tour, it's very easy to drink every single day because there's always someone visiting.
"I had to make a real effort on the tour. I'm 12 stone now. I started running. I've got into cycling as well."
The 28-year-old star admits one of the reasons he wasn't in his first three or four music videos was because he didn't have six packs like his One Direction pals and the likes of Justin Bieber.
Speaking on the 'Behind The Medal' podcast, he added: "I wasn't in my first three or four videos.
"I was the same sort of age as the One Direction boys and Justin Bieber and all these people who had six-packs and I was kind of like, 'Oh, should I look like this?' "
However, Ed has appeared in a number of music videos since then, including one alongside his wife Cherry Seaborn for his latest single 'Put It All On Me', which features Ella Mai.
The footage was filmed in their London apartment and it features a string of couples including Ed and Cherry, with the caption under their segment reading: "Back in high school, Ed and Cherry were crushing hard. They made out at the castle on the hill. A few years ago they reconnected, there were fireworks. They married in January 2019."