As kids at a buffet we would all load up on way more food than we could eat. Naturally, we would just play with that food, mixing up all the things we could in cups and dare each other to take a sip. I bet we weren't the only ones who did that.
Rightly so, food waste is inexcusable when we have people going hungry.
EDIT: With the planet being used up people are perfectly happy to just waste edible food. We're doomed.
How would that food in the buffet get to the hungry?
And really this would depend on a rich freeze drying industry. Imagine people driving around in trucks collecting all the uneaten scraps from children and adults plates. Sure we would not be able to handle to food safely, but we will be exporting it to countries that do not have as stringent laws on human consumption.
If the food hadn't been ordered, it wouldn't have been shipped, it wouldn't have been grown...
It's silly to directly relate the exact food a kid didn't eat on a buffet in Los Angeles to a starving family in Detroit, but that doesn't mean there are zero lines to draw.