As a rule of thumb, I tell myself that it’s better to throw away food than to overeat. (Preparing just the right amount is even better, but more difficult.)
What about saving for the next day, composting or donating?
As a former professional cook it burns me to see such a casual suggestion to waste food. I’ve worked for people who would weigh the food you swept up off the floor at the end of the day to illustrate waste.
Oh, for each stickler I’ve worked for who cared about waste, I’ve still worked for 3 others who couldn’t care less. I’ve seen heartbreaking amounts of perfectly edible food go in the trash can. Not even employees could eat it, they had to buy their own meals afterwards.
Totally, it’s fun to learn just how much our bodies can use! I use broccoli stems make broccoli cheddar soup :) If nothing else, freeze raw veggie scraps and meat trimmings/fat/bone for stock and turn them into soups or sauces. I freeze stock in ice cube trays, store in a gallon ziplock and throw one or two into rice, quinoa, etc.
Both professional and personal cooking vary widely depending on who’s doing the work. I’ve seen careful and careless practices in both.
You might be surprised though how leftovers are recombined to form new dishes, even in large scale operations. Working with what you got can be just as important as food safety, foundational knowledge or technique.
It helps to have a few go-to recipes that can accept a wide variety of ingredients in small portions. For me, I usually go to either omelettes, veggie burgers or fried rice / stir fry.
Donating is the hardest one for sure due to laws and logistics. I’ve taken to giving out my extra sourdough bread or cinnamon rolls to friends and neighbors, or have my wife take them to the office; there’s always one or two that we know we won’t get to before they go bad (if we want to maintain our physiques anyways).
For myself at least, saving food for the next day is rather difficult. Mainly because nowadays I very seldom cook food for myself, a lot of my food consumption is through ready made meals that I can just put in the oven or microwave. The packaging almost always warns that this type of food cannot be reheated so I don't save it. I think a lot of people do this.
Even if I do cook for myself I am often unsure whether it is safe to reheat the food, and for how long.
As long as you keep the food in the fridge and heat it properly when you reheat it (so it gets boiling hot) the vast majority of food keeps for several days in the fridge.
I leave pea soup and pot currys at room temp (19-23c) for 24-48 hours before I eat them; after that they keep for several days in the fridge.
If you live in a warm climate and/or leave food uncovered all day then you're asking for problems. In those cases I wouldn't reheat them..
The packaging is lying to you. Reheating is not a danger. Leaving food out for too long is a danger.
The worst case is that reheating doesn't reset the timer. If you put the leftovers into your fridge within a few minutes of eating, you have tons of time left on the timer, and don't need to worry at all.
As a former professional cook it burns me to see such a casual suggestion to waste food. I’ve worked for people who would weigh the food you swept up off the floor at the end of the day to illustrate waste.