I close to eliminated sugar, and reduced carbs, and completely eliminated highly processed foods. Over the course of 14 months I lost about 23lbs. I also cut meat consumption and alcohol, but wasn't by any stretch vegetarian or tea total. That's it. Apart from that I ate anything in any quantity I wanted.

I found the combination of things I cut back on reduced cravings and overeating. I cooked a lot more, especially bean soups to take to work for lunch. That has other benefits since I work in the land of $11 sandwiches. I tracked my weight every few days with a fitness app, which, for me, helped prevent backsliding because seeing that trend line go in the wrong direction is very irritating.

I don't have experimental evidence but anecdata indicates cutting sugar and alcohol are are the low-hanging fruit (cut way back on fruit juice, too).