There are only few things that are really sensitive towards low temperatures - cookie doughs, soufflé and maybe bread. For any other food preheating the oven ia just a waste of energy.
Food companies only write it on the instructions because the time the food needs in the oven is not valid when they have to count in the speed your oven needs to heat up.

[–] schmidtster@lemmy.world 16 points 10 months ago (1 children)

Element is on max while preheating the oven, this can overcook the surface of the food before cooking even starts.

[–] nul9o9@lemmy.world 3 points 10 months ago (1 children)

A simple example is a frozen pizza. The crust will overcook and burn before the toppings brown.

[–] Raxiel@lemmy.world 1 points 10 months ago

As I type, I'm eating previously frozen pizza I put in a cold oven then turned on fan mode at 180. By the time it reached temperature it was evenly cooked