Do You want the direct through and through answer? it's impossible. Because the subtlety of malpractice hides in all of us, in our nature, in human nature. Wasting is just another manifestation of that. The most hopeless and depressing thing about this is that when you try to make people understand how wasting food is bad and how it could affect us all in near future they all seem to just avoid it or laugh at our attempt or turn the whole thing into a meme. For example, African kids could have used this bla bla meme... And if you try to defend something against a meme, well, you're social networking portfolio is done, brother.

Now to address the elephant in the room, how do we solve this,? before giving a pragmatic answer ill give you a political one.

Because of a fixed demographic demand in foods, all the harvest are always sent to fixed markets depriving the other markets and thus depriving the other part of the population. And the basic supply-demand theory comes into play by making people careless about storing food as for where supply is more than demand its only natural. To stop it some extensive research and focused awareness might be able to stop these specific criteria of the food waste issue.

And the other issues are dependent on peoples lifestyle and area of living. Like when you have excess it is highly unlikely that you will be careful about storing food. Though sometimes it might depend on the way you were cared for and fed as a child. But habits can also be changed through via morale development. Though its impossible to waste food but it can be reduced if we try individual or united.