It would depend on how much of a calorie deficit you are in, in the first place. If you've been eating to gain size as it is, then a huge 2k calorie meal is probably not going to be utilized all that well- you'll end up storing excess calories, likely as fat if you don't account for the excess calories in the following meals/days, or during your workouts. If you're coming off a long diet, that many calories at once may still be stored, but more likely stored or saved to replinish glycogen stores, etc. before storing as fat.
In general the 30 grams of protein per meal limit is considered a myth.