Food isn't good or bad, and you aren't either for eating it. The trouble starts with the story that follows: one unplanned thing means the day is ruined, so you may as well finish the packet and start again Monday. That loop costs far more than the original food ever did.
Planned treats break the loop. Decide that dessert is happening on Friday, or that there's chocolate after dinner, and it stops being a test you can fail. Restriction is what makes food feel loud.
The mechanics still work in your favour: eat it after a meal with protein rather than instead of one, put the portion on a plate instead of eating from the bag, and sit down for it. Same food, completely different afternoon.
If a food genuinely can't be in the house without disappearing, that's information, not a moral failing. Buy the single serving instead of the family pack for now.