Even the homeless advocate orgs will tell you not to give money directly to the homeless. Most are addicted to something or other, or dumped out of the mental institutions to live on the streets, or occasionally a scammer (like well-heeled suburban teenage kids that dress in rags and go to the city to beg for fun... truly). Lost in the mix is the rare legit and recently homeless person for whom none of this applies, to be sure, but you never have a way of knowing that.
If you care, find a local org that cooks meals, has beds, or provides other services and give to them instead. You can even charge it on a recurring basis, usually. I'm atheist so it's a little weird to give to a local evangelical Christian church with a big "JESUS SAVES" neon sign that is the only option providing meals, but nothing is perfect...