"Gorge" may be a bit drastic - I'll usually arrive at a water source with a couple of drinks left, and polish them off. Then I filter a bottle, and drink my fill from that (maybe a half liter), then refill the bottle and head out again. That routine is based on sources about 2 hours apart.

I don't cook lunch, but cooking at a source would seem reasonable (or just haul a bit extra from the mid-morning source.)

If you're drinking substantial amounts of water, you might consider carrying along some Gatorade mix, for the electrolyte replacement.