If a food has a long list of ingredients that you don’t recognize, don’t look them up. Put it back and walk away! Buy as many one ingredient foods as you can. Consider going to a Farmer’s Market or local farm. Shop the perimeter!
I’m not suggesting that if you go to your Mom’s for Thanksgiving and she’s made her favorite Jello Salad and pie and you see the can of Crisco on the counter, that you become a food militant and refuse to eat it. Either eat it and really enjoy it, or find a way to discreetly dispose of it. But don’t give it to the dog! It’s not good for him either!