My baby had mostly formula, we trained him to take it room temperature or refrigerated. The bottle warmers are all crazy junk, we tried one and all it seemed to do was make the outside of the bottle uncomfortable to hold without warning the contents in an appreciable way. It's definitely worth a little more screaming early on to train to accept milk at any temperature. (Keep in mind, babies are classically conditioning you while you're conditioning them)
Also breast feeding doesn't work for all women either.
Infants have less ability to maintain homeostasis than older humans; there are good reasons to give them milk/formula at or near body temperature.
And there are bottle warmers that work quite well. (For formula, I've heard that there are devices that do measuring, mixing, and warming, do it all quickly, and do it well, but I've not personally used them.)
Room temperature feedings are really not an issue.
8 pound baby investing a less than 3oz feeding at room temperature is really not an issue. 100f vs 70f = 30 degrees * 3 oz / 128 oz ~= at most 0.7f temperature drop however this is spread out over time and a fairly extreme example to begin with.
It's about maintaining digestive track temperature to allow for proper ingestion of nutrients in which case room
temp (20c) milk or formula does hinder the process.
We didn't came up with warming it to 34-37c for no reason.
Serving it at 10-15c colder than body temp puts a lot of stress on the infants digestive system and prevents proper nutrient absorption.
> We didn't came up with warming it to 34-37c for no reason.
A lot of people do it because their parents did it. After you've trained your baby to prefer warmed bottles, they will likely throw a fit with room temperature bottles. I don't see how you could construct a sound study on this (because it's pretty hard to double blind warmed vs cold bottle), but you could probably do a correlation study on reported bottle temperatures vs miscellaneous infant maladies.
I was able to find that there are at least some studies on temperature in preterm infants (where better feeding response certainly justifies maximum hassle), but I couldn't find anything for infants that reached full term.
Nutrients are obsorbed below the stomach which releases milk fairly slowly and in plenty of time to warm up to very near body temperature. If you have some actual studies I would be happy to read them, but this seems physically unlikely because digestion is a very slow processes where temperature exchange is not.
Also breast feeding doesn't work for all women either.