# The Naked Scientists Forum

### Author Topic: do we burn calories when we think?  (Read 8333 times)

#### Emilio Romero

• Sr. Member
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##### do we burn calories when we think?
« on: 16/12/2008 19:00:31 »
Hello, I’ve heard that intellectual activity (such as deep thinking while playing chess) burns calories. I even read once that grandmasters actually loose weight after a chess game due to the calories burned.
However, I have not been able to find sound scientific back up for the claims.
So, do we burn calories (if so at what rate) when we think?
Thanks
emilio

#### DoctorBeaver

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##### do we burn calories when we think?
« Reply #1 on: 16/12/2008 19:02:41 »
The brain uses a lot of energy so I would imagine the more of it is being used, the more calories we would burn.

#### RD

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##### do we burn calories when we think?
« Reply #2 on: 16/12/2008 19:27:35 »
I'm quoting myself here  [:I] ...

Quote
The consensus is that the human brain uses energy at a rate of 20 Watts.

Energy consumption of 20 Watts is 20 Joules per second.

A Kilocalorie = Calorie = 4184 Joules.

So a human brain uses a (Kilo)Calorie of energy in about 3.5 minutes.

http://www.thenakedscientists.com/forum/index.php?topic=18589.0
« Last Edit: 16/12/2008 19:31:00 by RD »

#### Emilio Romero

• Sr. Member
• Posts: 224
##### do we burn calories when we think?
« Reply #3 on: 16/12/2008 19:38:43 »
Great, but do we burn the same amount while reading than we would when putting together a puzzle or playing chess???
Is there any difference?

e

#### DoctorBeaver

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##### do we burn calories when we think?
« Reply #4 on: 16/12/2008 19:43:26 »
We use different parts of our brain for different things. Whichever activities use more of the brain will use more calories. I am not aware of any direct studies, but there are plenty of illustrations of scans of brain activity on the net.

#### RD

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##### do we burn calories when we think?
« Reply #5 on: 16/12/2008 19:54:22 »
Not much difference in energy consumption between maintenance-mode (e.g. when asleep) and active (e.g. performing a task)...

Quote
Brain Signal Persists Even in Dreamless Sleep        02.10.2008

Neuroscientists at Washington University School of Medicine in St. Louis have taken one of the first direct looks at one of the human brain's most fundamental "foundations": a brain signal that never switches off and may support many cognitive functions...

"The brain consumes a tremendous amount of the body's energy resources—it's only 2 percent of body weight, but it uses about 20 percent of the energy we take in," says Raichle. "When we started to ask where all those resources were being spent, we found that the goal-oriented tasks we had studied previously only accounted for a tiny portion of that energy budget. The rest appears to go into activities and processes that maintain a state of readiness in the brain."
http://www.innovations-report.com/html/reports/medicine_health/brain_signal_persists_dreamless_sleep_119473.html

#### The Naked Scientists Forum

##### do we burn calories when we think?
« Reply #5 on: 16/12/2008 19:54:22 »