I have always heard that in a starvation situation, a human would die of thirst before lack of food. What if the person had a food source, just no water? Are there any types of food that would also provide enough water to survive? What if only meat were available? Or fruits and vegetables - would they provide the necessary water? If I had a month’s supply of, say, grapes in the desert, would I survive?
Interesting link on water content in food.
This won’t answer your question, but it might help.
Most foods will give you enough water to survive, if not necessarily thrive, so long as you’re not working up a sweat. And most fruits are almost entirely water, with just a few trace impurities, so if you’ve got a good supply of juicy fruit, there’s no problem at all.
Since the OP specifically mentioned grapes, I’d point out that eating a boatload of grapes will…uh…well, you won’t keep a lot of that water. They have a laxative effect in large quantities, don’t they?
The consensus seems to be that unless clean drinking water is available, one should not eat anything. The digestion of food consumes water. Eating loads of fruit (or berries here up north) seems like a good idea, but will result in diarrea, greatly increasing dehydration and hastening death.