I don't eat to the point where I feel stuffed.

I am not sure what you mean because the combination of "don't" with "until" is confusing. Here's what I think you mean. Here are three different ways to say it. a) "I eat until I feel full." b) "I stop eating when I feel full." c) "I don't stop eating until I feel full." The phrase "I don't eat until I feel full" is strange, because it means that you don't begin eating until after you feel full (which is impossible).

I don't overeat when I have a meal. I prefer to stick with the suggested portion sizes. Or, you can go with a colloquial expression: "I don't stuff myself when I eat."

Maybe you could say “I prefer to eat in moderation.”

Do you mean: "I don't want to eat if I am feeling full"? If so, you could also say: "I don't want to eat if I am full."