I have a somewhat complex method to avoid giving the fish an all-you-can-eat buffet. I use 1/2 of a Scop patch (I now know that you aren't supposed to cut them in half, but before I knew that I cut them and didn't have any bad effects), which i replace every 2 days.
For breakfast I eat a bagel with cream cheese, or some kind of fruit, and drink water. (Definitley avoid acidic things like OJ or coffee) Be sure not to overeat, eat just enough to last until lunch.
On the boat I've found that as long as what you drink is not acidic, it doesn't matter. One thing I've learned (the hard way) is that rapidly drinking water will cause hurling no matter what.
What you eat after the day's dives shouldn't matter the next day, as long as you don't overeat.