Bränner hjärnan mer energi vid "ansträngning"?

[sjowtajm]

Har en liten fundering:

Jag studerar nu under våren mycket hårdare än under hösten vilket gör att jag kräver mer fika i form av sockerspetsat kaffe och nege..., ehm, chokladbollar. Kan detta extra intag uppvägas av den klart mer krävande "process" som pågår i dumburken? Jag baserar denna teori på att jag har fått uppfattningen om att hjärnan bränner ca 10 % av den totala energin och att vid aktivitet borde det strömma mer blod till hjärnan än vid standby ...

... eller kommer jag bli fet !?!?!

[Spridis]

http://en.wikipedia.org/wiki/Brain:

Brain energy consumption
Although the human brain represents only 2% of the body weight, it receives 15% of the cardiac output, 20% of total body oxygen consumption, and 25% of total body glucose utilization.[80] The need to limit body weight in order, for example, to fly, has led to selection for a reduction of brain size in some species, such as bats.[81] The brain mostly utilizes glucose for energy, and deprivation of glucose, as can happen in hypoglycemia, can result in loss of consciousness. The energy consumption of the brain does not vary greatly over time, but active regions of the cortex consume somewhat more energy than inactive regions: this fact forms the basis for the functional brain imaging methods PET and fMRI.[82] These are nuclear medicine imaging techniques which produce a three-dimensional image of metabolic activity.

80.^ Clark & Sokoloff, 1999
81.^ Safi et al., 2005
82.^ Raichle & Gusnard, 2002