Once he has the PEG tube, it will be a lt easier. Each 259 ml can of formula counts as 200 ml of fluids. Yu will also have to flush the feeding tube before and after the formula, and that can easily be another 240 or 180 ml of fluids. If he takes six cans of formula a day, he will easily exceed the 2 liters he needs every day. This is the plan John's dietitian has worked out for him. We have been doing this for the last 3 weeks and John has been able to maintain his weight except for the couple of pounds he lost when he suddenly developed thrombosis. The dietitian advises against drinking too much plain water as it will cause an imbalance of the electrolytes in the body.