"I can't even get through one and a large fry what the hell"
If you drink beyond a certain amount of pure water without sodium and potassium then it can kill you
But one way to gradually increase how much food you can eat is to drink a little bit more water in a meal every day but not so much water that it makes you feel sick
And make sure you have the right amount of sodium and potassium with the water for it not to kill you