Kenny Chesney and Tim McGraw are currently criss-crossing the country on the Brothers of the Sun tour, and while the best buds are without a doubt in great shape, one of them can't help but tease the other with a temptation that's almost too hard to resist.

"Tim knows I've been trying to lean my body down so I can fit in the jeans I wear onstage," Kenny tells Lon Helton of CMT's Country Countdown USA. "I think he's figured out that on Sunday, I'll eat whatever I want. So, to test my will power he'll send me a dessert every day ... He sent me a whole red velvet cake one day, and he knows I love red velvet cake. I think he's trying to do anything he can so he'll be skinnier than me."

Even if Tim is trying to sabotage Kenny's efforts to stay fit, he may have to work a little harder. In the June issue of Men's Health magazine, the "Come Over" singer details what steps he takes to ensure he can fit into those skinny jeans and put on a high-energy show for fans. In addition to not having had salt in a decade, Kenny says he rarely eats bread or dairy products.

"You think you're sprinting on this treadmill," says Kenny. "When I'm up there it's like I'm at a constant sprint at a 15 level. But the thing you have onstage that you don't have in the gym is adrenaline." Because a two-hour performance in the summer heat can be incredibly taxing, Kenny starts training the January before a summer tour, beginning with a 45-minute strength training session, adding 15-minute high-intensity interval training as the tour approaches.

While he has never smoked or abused his body with drugs, Kenny acknowledges that he can't say the same about his alcohol consumption.

"I've probably been over-served a lot," he acknowledges. "You can't spend 19 years on the road and not have a few drinks."

In fact, once the tour is over, Kenny will head back to the Caribbean and tip back a few.

"I'm gonna have a couple of cold Coronas and listen to music and watch the sun move across the sky," he says. "And I'll try to relax and turn my brain off. If I could find the light switch to turn that off ... but I'm glad it's not off. I wouldn't know what to do. I'm like a shark. I've got to be constantly moving."

Kenny may want to celebrate with a Corona or two, and a slice or (or eight?) of red velvet cake -- once his Welcome to the Fishbowl album is released on Tuesday (June 19). Kenny and Tim continue their Brothers of the Sun tour with a show on Saturday (June 16) in Philadelphia, Pa. Keep track of their tour schedule here.