Well, this makes sense empirically. All of my ancestors came from arctic regions (if you go back far enough), none that I can recall were extremely fat, most only required one blanket for sleeping even during the coldest winters, all of them lived well into their late 80s and 90s but had brittle bones. Guess I'd better start taking more calcium and magnesium.
Swedish patriarch's first comment upon arriving in America: "Ya, sure...vell, ve go north!" ROFL! I always wondered why great-grandfather Alfred didn't bring the family to Florida.
When naturalist and explorer Alexander von Humboldt toured the Tierra del Fuego region (Southern most tip of Argentina), he described two different people who lived in the same region. One was tall and thin (...he went on to describe their abundant clothing) the other was short and stocky, almost fat.
The short stocky people were practically naked and two women rowed their canoe up to his ship to ask for supplies and he noted that both were topless and one was breast feeding an infant while the icy rain bounced off her shoulders and the babys' head.
The short stock people lived off the sea while the tall thin people lived off the land.
There were two different people living in harmony because they were not competing for the same resources.
Also, of the short stocky people, he noted that the women were in charge of the canoes and would tether them off-shore in the kelp beds and swim back to the shore when they were not in use by the men. (There was a sharp rocky coast that would destroy the canoes if tethered on the coast)
He thought this was so because women have more body fat than men and the water was icy cold.
I'm unaware of a need for magnesium supplements when a normal diet is consumed unless certain medical diagnoses are present.