Yes, we all try to follow that rule, sort of. Sleeve patients have their switch, so it isn't as needed, but since they rerouted your tummy as a bypass patient, your food just passes through, and even quicker with fluids if you drink and eat at the same time. My nutritionist doesn't care if I drink before I eat, but during a meal up to 30 minutes after, no liquids. Basically, your new tummy can't handle the volume and the liquids push all your food through, not allowing you to absorb the nutrients from the food. Now, on the other hand...if I eat an Oreo...or something tasty I am not supposed to eat...I drink as much as I can to 'push' it through quicker so I can't absorb the fat from it! Anyway, just think of your new tummy as a bend in a pipe, only 4 oz. big with no room for liquid once you plug it up with food, you want to get as much of the minerals and nutrients from your meals as you can while you can. It took me forever to be able to do this! But you can get used to it and do it! Best of luck!