Did you forget to pack away your winter fat layer ?

Posted by Dr Sandy on in Vitamin D | 362 Views | 2 Responses

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Is too much “winter” the cause of obesity ?

Skinny bean poles, the few of them that still exist, are set to freeze their tushes off in winter, because they don’t have any winter clothes.

Now, we’re not taking about a shortage of winter woollies, but rather a shortage of the insulating fat layer, which helps keep the body warm and toasty.

Winter woollies

Today, being fat is frowned upon, but back in the day…………… if you were carrying a few extra kilograms, as winter set in, you would have had a distinct advantage.

You see, for our ancestors to eat…………..they had to leave their warm cozy cave, to hunt down some dinner.

And finding dinner, in the middle of winter, would have been quite a challenge.

The fat would have had a definite advantage.

The fat advantage

For starters,

the extra layer would have helped keep them warm.
And, if food supplies ran low, which was extremely likely, their fat supply could be used to sustain them, until food supplies were restored.

Now to enjoy this fatness advantage, you needed to have JUST the right body chemistry…………….. specifically, you need to be insulin resistant.

Insulin resistance required

Yes. Being insulin resistant would not have been a liability, it would have been an asset. It would have ensured the fat cupboard was well stocked and it would have increased their thermogenic capacity.

Of course this insulin resistance, would have been transient.

The perfect biochemical storm, ensuring they survived winter and by the end of winter, the fat stores would have been depleted and insulin sensitivity would have been restored.

So……how did your body know, when it was winter ?

Clearly it couldn’t tune into the evening news to get the weather forecast. They relied on environmental cues. The big sign winter was on it’s way……………………… was the amount of sun exposure decreased.

Now when the sun goes on vacation, so does vitamin D.

The sun makes vitamin D

You see, despite the sun’s bad reputation, it is responsible for a rather important chemical reaction. The zaps of UV-B radiation, energize cholesterol in the skin, so t it turns into a vitamin D precursor.

It’s quite a process, but this precursor eventually turned into active vitamin D, which circulates in the body, turning various genes on and off. The official “gene” count is around 200 genes.

So, flipping this switch creates some serious changes in body chemistry.

Mmm… like flipping on insulin resistance ? Maybe.

Being fat regulated by the sun ?

The Vitamin D is definitely one of the signals used by the body to “know” when winter has arrived and when it is over.

A drop in vitamin D levels signals it is about to get cold, really cold, so the body should put on it’s winter coat.
At the end of winter, vitamin D levels rise, so the body “knows” it is time to put the winter clothes away.

A perfect system…………”Mother Nature” is so smart. The arrangement ensures your fat cell’s wardrobe matches the seasons – it keeps you warm in winter and cool in summer.

A perfect system, provided you actually spend some time under the sun, soaking up those UV-B rays.

365 days of winter

But modern man typically avoids the sun, either by hiding indoors or hiding under layers of protective clothing and creams.

Vitamin D deficiency or insufficiency is an invisible epidemic.

But it’s not the only epidemic. Obesity is also an epidemic, just a more visible epidemic.

The big question – are the two epidemics connected ? Maybe.

Obesity caused by very long winters ?

Lots of studies have shown that fat people tend to have low vitamin D levels. It has been argued by some, that this is a consequence of being fat, others see it as the cause.