Formerly svelte Brit-ex now food engorged blimp boy!

Amazingly, K-Fed‘s been Over-Fed!

Britney Spears has put ex-hubby Kevin Federline on a diet because he’s chowed down so much fatty food, he’s gained a whopping 85 pounds.

The 5-foot-10 former backup dancer weighed just 150 pounds when he married the singer in 2004. Now he tips the scales at about 235 pounds.

Back when they were married, Kevin used to chide Britney about her weight, but now the dinner table has turned. These days, it is Britney who is making the jokes – calling him K-Fatter-line and other names. "She’ll ask him, ‘When is the baby due?’" revealed a source.

Kevin, who cares for their two boys, isn’t working and rarely exercises – which infuriates the sexy entertainer. "Britney called him ‘a fat housewife,’ and he just laughed," said the source. "He says he’s gained weight because he is happy and content, but Britney says he is just fat and lazy."

While 27-year-old Britney is in her best shape in years, Kevin just keeps packing on the pounds. When he and their kids joined her during European concert stops, the singer was appalled that he fed them so much fast food.

"Britney insisted he go on a diet and stop showing their kids that it is OK to be fat and sloppy," said the source. "She’s worried his eating habits are setting up the kids to make poor food choices.
"Kevin was more than irritated by Britney’s diet demand, but he’s going along with it for now."

The 31-year-old dad feasts on fried foods and sweets, which Britney fears is becoming a pattern for sons Sean, 3, and Jayden, 2.

"Kevin loves pasta, burgers, fried chicken – and graham crackers loaded with jelly and chocolate," revealed the source. "He also drinks a lot of alcohol. Kevin loves to pig out."

The stay-at-home dad can afford to eat well. He’s receiving more than $40,000 a month in child and spousal support.

"And Kevin says he doesn’t have to worry about his looks," said the source, "because women still love him."

And not just for his semi-fame and bulging wallet.