This plus abundance of bad food. It's easier to stay thin if your diet is what we evolved to eat. That norm would take most people incredible will power to stick to with all the high carb food. Harder than not drinking.
Make a shopping list, stick to that, ignore and don't buy from the "bad aisles". If you have nothing "bad" at home and in your fridge you can't eat badly, and personally I have found that it is much easier not to buy than not to eat what you already have.
The problem, again, though is if the food you were eating was fulfilling an emotional need that you don't try to address after you start to make changes like this. That's why it's hard to sustain for a lot of people. You buy better food for a few weeks, and then suddenly you find that you're eating takeout every day again.
Having high carb food around at all does basically make it impossible. If you live on your own, clean out your cupboards and change what you buy. If you live with any other people... well, good luck getting them to also diet with you?