On reading the question do you have much brown fat; you are probably thinking I really hope not. However, you should be thinking the reverse.

So why on earth would you hope to have some brown fat? We nearly all hope for less fat, and brown fat sounds pretty yucky.

When we are born we have quite a bit of brown fat, or as it is also known, brown adipose tissue. The main purpose of brown fat is to make heat. Newborn babies are not able to move much, have little surface body fat, usually not able to shiver and their nervous system is not fully developed. Therefore, newborns use brown fat to help keep them warm in cool conditions.

White fat, the “regular” fat, has two purposes, one is protection and cushioning, particularly of our organs, the other is to store energy.

Putting out heat means using lots of energy, which of course, is using lots of calories. So brown fat uses calories, whereas white fat stores calories.

It was thought until recently that as a baby developed it lost all its brown fat. However, it has been shown by activity and biopsy that most adults do have some brown fat. Not a lot, but some.

Now it has been shown that the brown fat is activated when somebody is in cool conditions for an hour or two. This makes sense when the body is cold, it tries to heat itself. One way this happens is by shivering. Shivering is using your muscles to move, which generates heat. Activating brown fat is another way to heat your body.

So, generally, who has the most brown fat? Thinner people tend to have more than fatter people – less of an insulating layer of white fat. Younger had more than older. Those with lower glucose levels. Women had more than men.

This raises some interesting questions. If you kept yourself slightly cold how many extra calories would you burn? Would it be enough for weight loss? Are people who live in cold climates or cold houses likely to be thinner? If you keep brown fat activated, will the amount you have increase?

Should we all turn down the thermostat and take a blanket off the bed?

photo credit: Kimmie M

[tags]brown fat, brown adipose tissue, non-shivering thermogenesis, calories, baby[/tags]