Practice is never as interesting to watch as real competition. There’s a lot of inglorious repetition in getting ready for a competition, whether you’re a linebacker or a pole vaulter. Boxing may seem like an exciting exception to the rule, what with the speed bag, the punching, and all those other get-pumped-up training montage scenes.

Still, boxing has one huge piece of prep work that’s easy to forget about: staying in your weight class. Weight is everything in boxing, and maintaining that number is a slog. “I eat bread only once a week,” says Saúl “Canelo” Álvarez via a translator, “or maybe a serving of rice. But no more than once a week.”

Álvarez is the former middleweight and light middleweight champion of the world, and pound for pound considered the best boxer alive. He’s also one half of the most anticipated fights in the boxing world right now, a long-teased match-up against Gennady Golovkin, the holder of multiple world middleweight titles. Earlier this year, after Álvarez knocked out Amir Khan, he proceeded to challenge Golovkin from the ring, but now that fight likely won’t happen until some time in 2017. (Alvarez needs to work up to 160 pounds for the fight and Oscar De La Hoya, president of Golden Boy Promotions which represents Álvarez, says he needs work up slowly but, hey, the extra time for promotion sure doesn’t hurt.)

Right now Álvarez is preparing for a September 17 fight against Liam Smith, the undefeated light-middleweight world champion. For the fight Álvarez has to keep at a trim 154 pounds, which is why in the two months leading up to the fight he only gets to have bread once a week. The rest of the time, Álvarez is pretty much starch-less. And it’s as thrilling as a protein shake for dinner.

Between meals Álvarez snacks on things like cucumber and jicama, fruits and vegetables that deliver water and fiber without much of a calorie bump that help to fluff off hunger. But like his former opponent Amir Khan, Álvarez won’t go well-fed into a fight. “Feeling full can be a disadvantage,” he says. “You can have the best training but just feeling full can make you sluggish and cause you to lose.”

But as soon as the fight’s over, the muzzle comes off. “I do two months of strict dieting,” he says, “so after fight night I go for whatever my body is craving. It’s usually sushi. But after that I go home to Guadalajara and indulge in a lot of tacos before I have to start getting in shape for another fight.”

BreakfastEgg whites with ham and orange juice

LunchChicken with carrots, squash, broccoli and cauliflower

SnacksApples, cucumbers, grapes, jicama

DinnerProtein shake with no carbs

Luke Darby is a contributor to GQ, covering news, entertainment, and the environment. A Louisiana native, he now resides in Cleveland, and his writing has also appeared in Outside, the Dallas Observer, and Marie Claire.