With an appropriate workout/cardio regime then it won't hurt you (assuming your metabolism isn't so ****ty that you get fat just by looking at a McDs), but it's far from an optimum way to get extra calories in.
There's a host of better options: nut butters, olive/flax oil in your protein drinks, whole milk by the gallon, hell, bigger portions of home cooking..
Oh, and as for not wanting to cook, I say get off your lazy ass. Gaining quality weight isn't easy, you have to work for it. And I've just given you several options.
