I suspect most economists have a hard time with this sort of reasoning. The decision to discard food is a decision like any other economic decision. Deciding to discarding food is "bad" only to the extent that there is some sort of market failure. To be sure, there may be some un-priced externalities associated with waste, but these aren't often well articulated by advocates of food waste reduction. Even still, it isn't the decision to discard that is "bad", what is "bad" is the lack of a market to price the externality.
A useful starting point is to go back to first principles and understand the economic factors that "reasonably" or "rationally" lead people to discard food in the first place. That is precisely what Brenna Ellison and I have tried to do in a new short paper that was just published in the journal Applied Economics Letters.
The paper constructs a mathematical model of consumer behavior based on the notion that people take prices and wage rates as given and then choose how much time to spend working, how much time to spend in food preparation, and how many raw food ingredients to buy so as to maximize their well-being (which is defined by the meals they eat and the amount of time in leisure). In this so-called household production model, consumers are also producers: they combine their time with raw food inputs to produce meals, which are the ultimate source of value for the consumer.
It is actually hard to conceptualize "waste" in a model like this (or any economic models of optimization). I've heard heated debates between some of my fellow agricultural economists over this matter, and there is a camp that would argue (quite persuasively I might add) that there is no such thing as waste. In that view "waste" really would represent a mistake or an arbitrage opportunity. If someone valued my trash more than I did, they ought to be willing to pay to take it from me; if no one does, then (as I actually do) I pay someone else to remove it, who finds no other economical use for it other than to bury it and let nature take its course. In this more strident view, we might "discard" items, but a well functioning economy doesn't "waste" items.
All that is to say, in a mathematical model like ours, one has to have some way of defining waste. We define it as the the inverse of the amount of meals produced per unit of raw food input. A cynic might say: you've just redefined the marginal productivity as raw food inputs as waste. Guilty as charged. If you have a better solution, I'm happy to hear it.
In any event, this set-up allows us to view waste as a function of economic variables. We show that: