A Big Mac weighs 215g but has only 25g of protein. Add the french fries and coke and you basically have a whole bunch of carbs and fat.
Even their ice creams don't contain much protein. A large McFlurry with Oreo's is 381g but has only 15g of protein (and 85g of sugar).
source: http://nutrition.mcdonalds.com/getnutrition/nutritionfacts.p...