Want to eat pancakes? Eat a small amount. With butter. It's fine. Don't eat a stack that is shown in ads.
Want fries? Eat two normal potatoes fried in beef fat. Not potatoes the size of a human head.
It is conscious work to retrain your stomach, but it is possible. I'm saying this as somebody who just ate 2 slices of bread (1 sandwich) and now feels like I can't move, where before I'd easily eat 6 slices. That was my breakfast (at lunch), I haven't even had an earlier meal.
No bodily exhaustion, no pain, no excessive time commitments, no money (you even save money!), no feeling the need to punish and taking revenge on yourself, just being conscious.
Works well with alcohol consumption, too. Ask me how I know how those big red wine glasses which fit 25% of the bottle are bullshit, same as pints. Those are two portions, easily. Look at old photographs: The glasses are tiny.