The Take That star became depressed over his figure and lack of solo success following the band's split in the mid-1990s, but has managed to get to a weight where he feels "so bloody happy" since their phenomenal comeback.
"I'm at a weight that I'm just so bloody happy with and I feel amazing," he told Grazia. "I'm full of confidence. It's going to sound shallow, but being happy with the way I look makes me spring out of bed in the morning and want to live life."
Barlow also credited his wife of 11 years Dawn for supporting him throughout his weight battle.
"She has known me through thick and thin," he said. "She has known me at 17 stone, when nobody wanted to call me anymore.
"Dawn knows how weight has always been my enemy, how with every mouthful of food I have always felt guilty.
"I've actually had major problems with food for years and years. I realised that once I started to eat I couldn't stop."
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Watch the music video for Take That's 'Eight Letters' below: