It takes two weeks or more to starve to death. But you can die from dehydration in as little as two days. So it is more important to get enough to drink than to get enough to eat. This is especially true in hot weather. Staying hydrated is not just about getting enough water. You also need enough minerals. I try to eat oranges or bananas or drink orange juice or gatorade almost every day. If I don't get enough potassium, I get restless leg syndrome and can't sleep.
On a related note, I find that I am eating a lot more bread and drinking a lot more water than my normal diet just because they are fairly reliably available for free. "Bread and water" is an old form of punishment. I heard that it was done because it causes severe constipation. I have had a few days where I was very constipated, which is awful when homeless because finding a bathroom can be challenging. Since the last incident, I have tried really hard to get more free fruit and vegetables into me. So far, so good.
On a related note, I find that I am eating a lot more bread and drinking a lot more water than my normal diet just because they are fairly reliably available for free. "Bread and water" is an old form of punishment. I heard that it was done because it causes severe constipation. I have had a few days where I was very constipated, which is awful when homeless because finding a bathroom can be challenging. Since the last incident, I have tried really hard to get more free fruit and vegetables into me. So far, so good.