User blog comment:IamJakuhoRaikoben/Chapter 245: The Unbranded Man, Review./@comment-3987368-20110730184547/@comment-3290324-20110730184915

Actually he did it eat, if you look on the page after Laxus did it Natsu clearly states Thanks for the meal. He can use another element, but he can't eat one. If he learns an elemental Magic naturally then i'm sure it would have no effect, but not if he ingests the element because it was already stated earlier in the series that he can only eat fire.