Tiny piece of damn near useless advice: you can eat wood for 1/4 of a heart. Use bombs to blow up all the trees (twice) and cook the wood at the pot. Just don't make the mistake of throwing in four pieces thinking you'll get a full heart. It's time consuming (I had 55 at one point), but you never know what'll save you in the end. I finished the middle trials w/a measly 2.5 hearts left, so those wood dishes saved my ass.
Also, some stuff like acorns and wildberries don't add anything to your dish. You can throw them at fire (or make fire w/torches and some wood) and go from 1/4 of a heart to 1/2 of a heart if you're having a heart emergency. Of course, you can save them until you get to a pot and get the same result, IIRC.