If anything, Americans should be throwing out even more food. With the astronomical obesity rates, I don't think we should be encouraging people to finish what's on their plate.
If that seems wasteful to you, then I assert you're not looking at the big picture. Habitual overeating causes even worse portion control in the future, which causes even more food waste in the long run.
Portion control means serving yourself less, but failing that, it means stopping when you're full, not continuing to eat what you've served yourself in the name of preventing food waste. Once you start doing that, you reinforce the behavior of serving yourself too much and eventually begin to crave more food than you should be eating. Portion control is unrelated to how much food you make, assuming you have a refrigerator and don't think yourself too good for leftovers...
> not continuing to eat what you've served yourself in the name of preventing food waste
You could also cover your plate and put it in the fridge. Doing that requires the same amount of self-control as your prescription of clearing your plate in the trash once you're full. Both are hard for many people to do.
It's easier to exercise restraint when serving than when eating. For example, Google successfully reduced food consumption and food waste by reducing the plate size in cafes. [1]
> Portion control is unrelated to how much food you make
Not entirely. Even in the fridge, food will only stay good for a certain amount of time. Most people won't want to eat the same thing more than 3 meals in a row. These are also reasons for overeating or throwing food out.
If that seems wasteful to you, then I assert you're not looking at the big picture. Habitual overeating causes even worse portion control in the future, which causes even more food waste in the long run.