Presumably, if you have X food being produced by farms across the country, and people eating it, but split between restaurants (Y) and home (Z)... I would expect X to roughly equal Y + Z.
I would also expect Y + Z = total food eaten and not see any change in the value of Y + Z regardless of how food shifts between the two.
So how can you take away Y, but not increase Z at the same proportion?
Guesses: 1) Restaurants use a lot more ingredients? Seems unlikely since margins are so low.
2) Consumers reduce waste because they are not balancing getting food from two sources and are more likely to eat everything in their fridge? (My wife, son and I experienced this after we found out our son has food allergies to more than nuts and we basically only eat home cooked food), but I don't know if that is big enough.
3) Something else?
My gut tells me we are seeing a reduction in food waste which is due to less supplies, people being more careful. IDK.