KANSAS CITY, Mo. -- The Dark Knight has his own kryptonite, to use a Superman term.

In a feature in which he mostly rails against the media, New York Mets ace Matt Harvey told the Observer about a recently discovered food allergy.

“I’ve been struggling pretty much my whole life with a lot of stomach issues, energy levels and things like that,” Harvey said. “I always thought it was just me. My dad always says his side of family always had stomach issues. This and that, things you really don’t want to discuss with people. I’ve had bad stomach issues from when I was a kid. I went gluten-free one time, but that didn’t really work.”

He told the Observer he underwent testing in January while working out at Scott Boras' facility in Newport Beach, California.

“It came back that I had a severe allergy to eggs. And that was something that I was eating pretty much every day that was basically poisoning my body,” Harvey said.

Harvey since has dropped eggs from the diet. He noticed “big-time changes in my energy level, in my sleep."

He added to the Observer: "I don’t feel bloated all the time. I was constantly feeling bad and I kind of got used to it over the years. But now that I’ve been off of eggs, now I know how feeling good feels.”