Slack is highly underrated.
This also turns out to be a serious problem in advocating for efficiency vs. growth.
Efficiency maximises at 0% wastage. Growth is (in theory, though very rarely in practice) open-ended. At least in the short term, growth compounds, whilst efficiency tends to asymptotically approach some minimum.
I'd had this realisation years ago in various efficiency drives (energy, water usage, etc.). The region that started in a more efficient and lower-usage state often faced a greater challenge than one which was profligate, as the latter would (usually) have an easier time cutting usage.
That's not always the case --- a region might become wholly dependent on profligate wastage, say, in the form of air conditioning or heating, in ways that are difficult to substitute for or curtail, especially given infrastructure which makes limiting such activities difficult. But as a general rule, having more fat to cut should actually increase options, all else equal.
The usual figure I see is that food wastage is about 30--40%.[1] That figure's been remarkably stable over most of the past 100 years, though when the wastage happens has shifted dramatically toward the end-consumption phase, that is after a tremendous amount of additional energy has been applied in the form of transportation, processing, and cold-storage. It's much better to toss unusable food in its raw state on the farm rather than as leftovers from your fridge (harvested, transported, refrigerated or processed, merchandised, bought, driven home, cooked, refrigerated again).
There's some wastage of imperfect fruit and vegetables, yes, though you'd be amazed at how much of that actually is incorporated into processed foods (dishes, smoothies, beverages, etc.) or used in animal feed earlier in the supply-chain.
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Notes:
1. E.g., US FDA: "In the United States, food waste is estimated at between 30–40 percent of the food supply." <https://www.fda.gov/food/consumers/food-loss-and-waste>. An arbitrarily-selected 1977 citation of the 1974 growing year suggests about 30% food wastage at the time as well ("the combined [food] loss ... could have fed an estimated 49 million people"): <https://www.google.com/books/edition/Food_Waste_an_Opportuni...> Food Waste - an Opportunity to Improve Resource Use Department of Agriculture : Report to the Congress, US GAO (1977). I've seen similar figures in works on resource utilization / limits dating to the 1950s.