I grew up at a time throwing away food leftovers was akin to sacrilege. It could earn one a thorough beating or unplanned fasting. Fridges existed, yes, but I never really touched one until I visited a relative in the city.
There was no room to pack that little food you were too full to finish. One was reminded of that child sleeping hungry in the streets, or people who only had a meal a day, or none. The guilt trip made us clear everything we served. It taught us to serve only what we could consume, and add only if necessary. Today’s parent is more tolerant; if a child does not feel like clearing their plate, that food can be discarded. So, we throw food that has gone bad, that we think has gone bad but hasn’t, or what we do not feel like eating. Some food ends up in the bin without passing through the table.