Oh, come on. Essentially you’re saying that if I 'm outside on a cold day and I eat some ice cream, my core temperature could drop enough to kill me?
Generally, no matter how cold the outdoor temperature is, I think most of the ice cream that’s basically melting in my mouth is pretty much above 32 degrees F by the time it hits my stomach.
Then again many animals eat their food while it’s still warm from a fresh kill.
Cold is cold, it doesn’t matter whether it’s coming from inside you, from outside you, or a little of both. The warmth of your body core is what matters most to survival, and cold foods go straight to the core. No, a bowl of ice cream on a cold winter day won’t kill you. But if there’s no external heat, and you eat quite a bit of frozen low-energy food, it can help you reach hypothermia faster. This is why all the survival manuals say be very careful about eating snow to hydrate yourself. However, I would say ice cream is somewhat better than snow, because it has a lot of energy that your body will convert to heat.
Re: Frozen food - when seriously winter camping, people will sometimes carry what they plan to eat close to their body during periods of high activity to warm it up before eating.
No, I’m not saying ice cream on a cold day will kill you, just that you have to be careful of hypothermia if you were eating frozen food all day every day in the middle of winter with no heat in a van down by the river.
If you’ve got plenty of food and your core temperature is normal then eating frozen food is probably fine. If you’re freezing and starving and borderline hypothermic already and all you have is a big stack of frozen food it would be a good idea to try to heat it up before you eat it. And especially important would be to melt the snow rather than eating it, since of course you don’t get any calories from water.