I totally relate! I am using a meal delivery program for most of my daily eating and it was a real eye opener as far as portion control goes. These meals are generous, they fill one of my dinner plates. But, when it's gone there are no seconds. And guess what---I'm full. So, eating more than one plate full was a bad habit. Sure it was tasty, but I really didn't need more food. It was available and it was a bad habit.
I applaud your approach. I think getting a firm grasp on this issue is an excellent way to start!. Here are a few things that have helped me:
I sit down and eat dinner with my husband. I focus on enjoying what I do allow myself to have. No more unconcious eating.
If I eat out, I only eat half of what I ordered. Again, I'm full but if it were all there I'd eat it anyway. Just ask for a to-go box when you order your meal and immediately put it away.
I have a couple of favorite dishes that just make eating enjoyable. I have invested in a few smaller snack or appetizer dishes. When I do have a snack I only take out one serving (check the back of the bag, box,etc.) and put it on one of these pretty plates or bowl. I no longer grab a cereal bowl and fill it to capacity with ice cream. I measure out a serving and put it into a custard bowl. It would look so pathetic in a regular bowl but in that little custard cup it looks just right! That's just an example but it really helps on every level.
Measure out what a serving of whatever you going to eat. Most of us have no idea what a 'serving' should be.
Make the calories you eat count! Add fiber rich veggies, whole grains, sensible portions of protein to each meal.
Stay away from the kitchen after you're done eating!
If after 20 minutes you are still hungry (and it takes awhile to recognize true hunger) then allow yourself a small snack --not seconds!
Say out loud to yourself--I'm full. I don't need anymore.
That's all that's coming to me but this has helped me alot. I'm sure you'll get lots of good advice.