(Possobly the same for like Lapland and folks on the same equatorial line up in the permafrost.) I think it feels comforting to humans to eat a packet of grain, veg and protein (dairy optional), soothing because you can hold everything you need in your hand. Also deliciousness.

I can picture early humans, practicing endurance hunting, with little packets of food, perhaps wrapped in an edible leaf, to keep their strength up following the mammoth herd, and someone having an idea.