I never go to the gym - I can't be doing with it. But I run up and down the stairs, wash my feet in the basin to keep supple, and I don't eat things that have a pulse.
Even clingfilm - if it's gone over a salad bowl, take it off, use it again. I wash out carrier bags; I save brown paper from parcels. I save string; I save ribbons. I separate all my bits and pieces.