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Why preheat oven? Answered

I rarely bake. 
I understand preheating a pan when cooking somethin like eggs- so they dont stick. 
When I toss a squash or somethin in oven, it seems like preheat is silly. Y? N? M?


To put it simply, if you put food into a cold oven, it will not cook. Baking is quite different than stovetop cooking and relies heavily on timed cooking at specific temperatures. Really though, you should heat your pans before adding your ingredients as well. Food always cooks better in evenly heated surfaces, and heating a pan with your cold food in it will not achieve that result.

Ovens are variable, and take different amounts of time to reach the optimum cooking temperature, which would be impossible to account for in a single recipe.

Too slow, things will dry out before cooking. Too quickly, you might burn them.

its a time thing, your food cooking time has been optimized to deliver constant results.

If you got a pizza that takes 16 minutes to cook at 400F then you have to start with an oven at 400F. if you oven takes 10 minutes to preheat to 400F then your pizza was only cooking for 6 minutes.

your microwave oven does the same thing. It wont start the countdown clock until the magnetron is at 100% but that is only like a couple sec difference.

same thing when the directions say to thow in frozen vs to let it sit on the counter while the oven is preheating.

now if im cooking something that is going to take around an hr to cook or more, then to me the time to preheat is negligible, and ill throw that bad boy in at the start .

It's the humane thing to do to food. Would you stick a lobster in a pot and then bring it up to a boil?

I think it depends on what you are cooking. The elevated temp is needed to set certain foods like you need the heat to activate the gas/yeast/leavening in baked products to get something fluffy. It has an effect on the texture of the food. You try that with a lasagne or maybe squash, it comes out mushy. But I think to a frozen dinner, heat is heat. Oh, and to a pizza, it would get soggy in the defrost phase, I think you want to sublimate out the ice.