An NBA basketball is 9 inches in diameter. I've included two cross sections of ball, which overlap across Sean May's waist. As you can see there is slight overlap, probably about an inch and a half. This leaves us 16.5 inches across the front of Sean's waist.
If we assume that the back of his waist is the same as the front, we're currently at 33 inches. Since Sean is a three-dimensional being, we have to account for his sides. If we conservatively estimate his thickness at 2/3rds of a basketball, we have 6 inches on both sides.
Front (16.5) + back (16.5) + right side (6) + left side (6) = 45 inches
Which in turn, explains why this happens:
When the first suggested result of your name is that your fat, rather than that you play professional basketball, it's probably time to re-examine your eating habits.