Brown Fat, Triggered by Cold or Exercise, May Yield a Key to Weight Control

NY Times ^ | January 24, 2012 | GINA KOLATA

[neverdem]

Fat people have less than thin people. Older people have less than younger people. Men have less than younger women.

It is brown fat, actually brown in color, and its great appeal is that it burns calories like a furnace...

--snip--

The brown fat also kept its subjects warm. The more brown fat a man had, the colder he could get before he started to shiver.

Brown fat, Dr. Carpentier and Jan Nedergaard, Dr. Cannon’s husband, wrote in an accompanying editorial, “is on fire.”

On average, Dr. Carpentier said, the brown fat burned about 250 calories over three hours.

But there is another type of brown fat. It has been harder to study because it often is interspersed in the white fat and does not occur in large masses. Investigators discovered it in mice years ago. Now, in a recent article, Bruce Spiegelman, professor of cell biology and medicine at the Dana-Farber Cancer Institute, and his colleagues report that, in mice at least, exercise can make it appear, by turning ordinary white fat brown.

When mice exercise, their muscle cells release a newly discovered hormone that the researchers named irisin. Irisin, in turn, converts white fat cells into brown ones. Those brown fat cells burn extra calories.

Dr. Spiegelman said the brown fat he studies is different from the type that appears in large, distinct masses in rodents, the type Dr. Carpentier was examining in his subjects. That brown fat is derived from musclelike cells and not from white fat.

Dr. Spiegelman suspects that humans, like mice, make brown fat from white fat when they exercise, because humans also have irisin in their blood. And human irisin is identical to mouse irisin...

[aimhigh]

Grrrraaaaavvvvyyyyyyyy

Amen. I like gravy as salad dressing!

[wolficatZ]

I’ve had weight issues in the past, it’s always a struggle.

Is there a **FAT FREEPER PING LIST**?

Someone should start one..

“Don’t forget the gravy!”

http://youtu.be/BmtEI9NWuz0

[RegulatorCountry]

Brown fat is fat that burns calories? Sounds to me as if brown fat is fatbeing burnt for calories. Big difference there, and one that comports with the layman understanding with the latter, but an interesting headline and potential grant money generated by the former.

[neverdem]

Brown adipose tissue oxidative metabolism contributes to energy expenditure during acute cold exposure in humans FReebie

Yes, even human brown fat is on fire!

FReepmail me if you want on or off the diabetes ping list. Comment# 1 links an abstract too.

[grey_whiskers]

Like, *PING*, dudes and dude-ettes.

Thanks, neverdem.

[LucyT]

Brown Fat, Triggered by Cold or Exercise, May Yield a Key to Weight Control

Thanks, grey_whiskers.

[Myrddin]

Irisin injections.

As long as introducing external irisin doesn't result in suppressing normal generation in your body. That may well suppress levels making it harder to derive a benefit from exercise.

[LibertyRocks]

Hmmm... They say it’s triggered by cold, huh? I wonder if I go stand outside for 10 mins. a day up here in Northern Wisconsin without my coat on if I can develop some brown fat that way? (My guess is that I’d only end up with black fingers, toes, ears and nose! It was -15 the other day! LOL)

Another hmmm... if cold triggers this “good fat” to be produced then why are so many of us up here in Wisconsin, on average, so heavy? (Oh, yeah... I guess it could be the beer, and cheese, and beef, eh! LOL)

Well, anyway, I’ll be sure to let you know if I figure out a way to make it work! I promised my doctor to start walking more though, so maybe if I walk in the cold it will be like walking twice or something!?! LOL

[aruanan]

Mice given irisin lost a few grams in the first 10 days after treatment, the study shows, and certain genes involved in powering the cell were turned on. Irisin also appeared to reduce the damage done by a high-fat diet, protecting mice against diet-induced obesity and diabetes, according to the paper, whose first author is Pontus Boström.

Here's a scenario: a lab mouse weighs about 20 grams. We'll take "a few grams" to be at least 3 grams. Over the course of 10 days, the mouse lost 15 percent of its weight, replaced by a smaller amount of brown fat that is so metabolically active in a futile cycle that it was able to burn up 15% of the mouse's weight in body fat. So for a 200 pound guy, this would be equivalent to 30 pounds of fat. At 3500 kilocalories per pound, that's 105,000 kilocalories, or 10,500 kilocalories/day.

Unless someone finds a way to up or down-regulate the futile cycle in these brown fat cells, they will continue to metabolize fat at that rate. Given that the majority of the body's metabolic energy for basal and resting metabolism (including that of skeletal muscles) comes from fat, those brown fat cells will be competing for dietary fat once stored body fat is depleted. So in order to have enough fat to fuel BMR and RMR, the guy would have to consume his normal amount of fat in about a 2,000 kilocalorie diet (and a lot more if he's physically very active) plus another 10,500 kilocalories of fat to fuel the futile cycle of the brown fat cells, lest they rob him of the fat needed to maintain basic life function.

This would mean that his energy costs (food) would increase by over 500% (10,500/2,000= 5.25). Depending on how many people got this as a treatment for obesity (say half the population, since about half the population is supposed to be "obese"), the nation's food industry, including farming, would have to be geared up incredibly to meet the demand.

This would have an impact on use of electricity and fuel to process, store, transport, and sell all that food. It would also have an impact on someone's food budget by increasing it more than fivefold for each brown fattie.

The increased metabolism of these brown fat cells is dissipated as heat. So this would have an impact on clothing (you'd need much less of it), on winter heating bills (it would be less since you'd feel a lot warmer since keeping the individual warm without shivering is the function of brown fat in small mammals--unless you had a mixed family in which you'd probably have to have separate, much cooler rooms for the brown fatties), in the summer, though, you'd have to have much higher cooling bills.

I'm sure there would be protest groups decrying the horrible waste involved in a 500% increase in food for a certain number of individuals only for the purpose of getting rid of some fat when people elsewhere in the world are starving.

And all for what? Just to burn stored energy in a futile cycle to produce heat so that people who already consume more than their bodies need can look like someone who does not by burning five times the amount of food energy.

[Bloody Sam Roberts]

As long as introducing external irisin doesn't result in suppressing normal generation in your body.

I know nothing of irisin but I look at it as a TypeII diabetic on insulin. It acts as a supplement for the normal or limited pancreatic production of insulin.

[MHGinTN]

Where in the mammalian body is this Irisin produced? ... The tree of life provided something (perhaps and enzyme) which caused the aging process to be suspended. Whatever was that enzyme or whatever, the human body did not produce it. At least this Irisin is produced int he mammalian body.

[aruanan]

The tree of life provided something (perhaps and enzyme) which caused the aging process to be suspended. Whatever was that enzyme or whatever, the human body did not produce it. At least this Irisin is produced int he mammalian body.

As you recall, A & E never did get to the tree of life. They were banished before that could happen.

[aruanan]

The brown fat also kept its subjects warm. The more brown fat a man had, the colder he could get before he started to shiver.

Imprecise. It should read, "The more brown fat a man had, the colder the temperature he could experience before he started to shiver" since the uncoupling mechanism in the mitochondria in brown fat results in the production of heat rather than oxidative phosphorylation.

[webstersII]

Michael Phelps, the Olympic swimmer, ate approx 11,000 calories per day when he was training.

I saw an analysis that showed even at maximal rates of training he couldn’t possibly burn anywhere near that many calories.

But when you factor in that he was losing body heat by staying in a pool for many hours a day, the caloric intake makes alot more sense.

[Pining_4_TX]

Actually, there was some guy who sat in cold(ish) water every day for 20 minutes or so and did lose weight, but I don’t know how many people could stand to do that. AND, it might not work for everyone, so I’m not tellin my fellow Freepers to go jump in a cold bath! ;-)