L.B.
Giving in and letting him have Cheetos or cookies is teaching him to hold out for the bad stuff.
Don't cut back on his fluids, esp if by those you mean water and watered-down juice. He needs to keep hydrated.
Don't force the food issue. Don't punish him for not eating. Just have snacks avaiilable at all times, healthy, nutrient-dense snacks. The Dr. Sears Baby Book has some great tips on this. Use an ice cube tray, fill each little square wiht a different type of snack: carrots, hummus, oranges, raisins, etc. Let him "graze" through the day. Don't let him run through the house with food in his hands, though. That's a choking hazard. Keep him company and entertain him at the table while he takes a pit stop for a nibble. And provide some toys that stay there and are his "table friends."
Forcing it won't work. But when he's hungry, he'll eat what he needs. Also, remember that his stomach is about the size of his fist!! So don't expect him to eat much at any one sitting!
L.