Mikiah Kreps stands in the far corner of an old warehouse, beyond the black curtain, folding chairs and boxing ring, and sips on her second Pedialyte of the day. This one is strawberry. The first was mixed fruit. “I like that they have less sugar than Gatorade,” she says. Kreps fasted until after 11 a.m. weigh-ins to ensure she made the cut, then feasted on Greek yogurt, fruit, vegetables and pasta. She has sweet plans with friends at a local restaurant later this evening. Kreps scrolls through photos on her phone, stopping on a screenshot of a monstrous milkshake. It’s topped with a cinnamon roll. “That’s for after the fight.” Boxer Mikiah Kreps works out with Hector Alejandro at the Gonzalez Boxing Club in Niagara Falls. (Mark Mulville/Buffalo News) Kreps, 22, is a reigning national boxing champion at 119 pounds, having won the USA Boxing Elite National Championships in December in Salt Lake City. She is ranked the No. 1 female in the country in her weight class. But on this mid-April night, the Niagara Falls native moves up to 125 pounds to defeat Casey Costanzo by split decision, 3-2, in the New York State Golden Gloves championships at Buffalo…