That's simply not correct.
If you take in more calories than you need right now, your body will simply store them away for later, and you can eat a little less later on.
Given that it's a lot easier to overeat than to undereat in today's USA, the rest of chain proceeds as follows:
While you can eat a little less later on, you probably won't. Rather, due to eating while already full, your stomach will expand, and you will thereby overeat at subsequent meals (because food is plentiful). Eventually you will be at risk for health complications due to weight. An early death due to weight-related causes is surely a great waste of those extra calories.
Who said this was going to be easy? Why is everyone always looking for the "easiest" solution? We're talking about doing the right thing (TM), not the easiest.
I see what you're saying, I don't think that line of reasoning has to be true.
You're saying that if I choose to fill my gas tank instead of my weekly $40, I'll drive more and more and more. Not true. By filling my tank today, I'll still drive the same amount as normal, I just won't need to visit the gas station as often as usual.
Often when I'm cooking dinner, I'll say something like "I don't need a lot, I had a huge lunch" etc. The opposite works well too. i.e. "It's only 11am and I'm starving, because I had a tiny breakfast."
Limiting how many calories you eat by throwing out the "extras" is like limiting how far you drive by pumping "extra" gas onto the ground.