Is it a MUST to have whey ? NO! But can you really get that much protein through food ? I prefer to get at least 2 gramms per kg of pure protein..Of course not on all days. But you need to figure out what your goals are,how much kcal do you spend etc...And honestly if you want to get the same amount of protein as "animal" protein ( chicken etc) and whey protein powder ,getting raw and real stuff is much more expensive. So the best thing to do is to get a combo of those two... 
of course you can get enough protein through food. as MrBig said, sort of, a good rule of thumb for minimum protein intake if you're working out regularly is one gram per pound of lean body mass, or 2.2g per kg of lean body mass. say you're 175lbs at 11% bf. oh, hey, that sounds like me. that's 155lbs of lean body mass.
breakfast: 4 eggs, 2 cups milk = 67g protein
lunch: chipotle burrito with chicken, beans, cheese, sour cream = 60g protein, 100000000g of deliciousness
dinner: 8 oz. beef, 2 cups milk = 66g protein
total protein = 176g, you've met your requirement for the day
also, whey protein
is animal protein. it comes from a fucking cow. whey is nothing more or less than a convenient and inexpensive way to add more protein to your diet. i rely on it more than i should, personally.
also, don't bother with whey protein isolate or fancy shit like that. plain old whey protein concentrate is fine.