Here's the thing - if it has a label with ingredients - don't eat it - seriously.
Stay around the outside of the supermarket (veggies, fish, meat, some dairy).
I started doing this about 2 years ago - lost 55-60 lbs and maybe 10-15 years off my chronological age (66). I thought I was old, but I wasn't - it was just the processed c*** that I was eating (wheat, sugar, starch etc).
Here's an interesting article about cereals:
10 Grain-Free Cereal Recipes & More Breakfast Ideas | Satisfying Eats
You really can control your diet - and it's pretty simple.