I can't speak for the rest of the world, but most of the Americans I know got admonished by their parents "Don't waste food!"
I think that's bad advice.
Wasting any sort of resource isn't good and should be avoided. But, there's a lot of other things at stake when you're talking about food. For instance, your time, your energy/health, and money.
Having gotten this strong admonition to never waste food growing up, I always felt guilty if I went out and bought some fruits or vegetables that I wasn't sure if I could finish before they went bad.
The end result? No food in the house, so go out to eat. Pay more, eat worse food.
That's stupid. That's really stupid.
Much better to buy 5 apples a week and throw 1 away, than to buy no apples and eat higher-priced lower quality food.
This has been surprisingly difficult for me to mentally re-wire - it's okay to waste food. It's not good, but it's not so bad either. Certainly, wasting food shouldn't be sacred apart from other kinds of resources like time and money - and most importantly, your health.
Waste some food if it helps you reach your goals. It ain't so bad.