No matter the age, we could all do this. Whether to save money ourselves or to give the money that we save to charity, a dollar a day on food really is possible!
Think BIG when it comes to buying food... a carton of eggs, a loaf of bread, a bag of rice, a 5 pound bag of potatoes, packages of ramen noodles, etc. You get the most for your money with these.
Instead of buying 12 packs of soda, crates of bottled water, etc., buy a sports bottle from the Dollar Store and keep re-filling from your kitchen faucet. Water tastes nasty? Buy a lemon juice squeeze bottle (my local grocery store sells them for 99 cents), use a few squirts, and voila! Lemon water.
Good luck!