The former dancer - who was married to the pop star for two years - claims he was so depressed following their split in November 2006 that he began gorging on food and at least 24 cans of fizzy drink every day until it got out of control.
Speaking to US talk show host Bonnie Hunt, he said: "Anybody who goes through a divorce is obviously going to be depressed. I hit 30 years old, I stopped dancing, I'm sitting around on the couch playing with the kids here and there, getting lazier and lazier and getting fatter and fatter and fatter.
"I drank 12 to 24 cans of soda a day - not diet. That was all that I drank. That was my coffee, that was my candy - that was everything. I ate pizza and macaroni cheese. The combination of the two just added up real fast."
Kevin, 32 - who is currently trying to lose weight on the US reality show 'Celebrity Fit Club: Boot Camp' - claimed it was paparazzi pictures of him sporting a bulging stomach at a hotel pool which gave him the push he needed to get back into shape.
He said: "That was a breaking point for me. I was in Miami, I didn't even know paparazzi were up in the hotel - I was out at the pool with the kids. A week later I see that picture and my Mom's telling me I'm at an unhealthy weight."