The shitty feeling you get straight after eating a McDonalds meal, usually coupled with a 'still hungry' feeling. Usually due to all the additives and addictive ingredients in the food.
Symptoms include bloatedness, tiredness, feeling sick, feeling ridiculously full but still wanting to pump your face full of food; We call this phantom hunger. Recent studies show that McDonalds Hangovers are most common on Sunday's, with 62% occurring on this day.
Fat Girl: Man I feel aweful after eating that McDonalds but I still want more. I think I may suffer from constant munchies(Phantom Hunger)!
Fat Boy: Nah, thats just the McDonalds hangover kicking in. You are now a Maccy junkie(education)!