Part of the show Do you burn more calories when thinking?
Haley Walsh asked:
I've noticed I am very tired after a day at uni, even though I am sitting most of the day. I have heard that brains burn approximately 20% of our daily calorie intake, but my question is: Do brains burn MORE calories when you're thinking really hard?
We put this brain teaser to nutritionist Toni Steer...
Toni - So, itís absolutely right, the brain does require round about 20% of your daily energy intake. The brain relies on glucose; it has to have glucose for energy so unlike other parts of your body, for example, other organs or muscles which can use fatty acids, the brain has to use glucose and it needs around about 120 grams of glucose a day. Most of the evidence indicates that, actually, you donít see a significant increase in energy consumption with people doing mental tasks. There have been some techniques where they can scan metabolic activity in different regions of the brain and itís looking at how the glucose moves and is utilised in different regions, and there is some suggestion that when youíre given a specific task you see more metabolic activity and glucose utilisation in different regions of the brain. But the overall impact of total energy requirement is very minimal and so the idea that if youíre going for a dayís lecture at university you need several chocolate bars, Iím afraid is not true.
Chris - Damn!
Toni - Itís not going to happen. Maybe the tiredness could be many other factors and, actually, one of them is good hydration. So tiredness and not being able to concentrate is often about making sure youíre well hydrated.
The only times I recall losing weight significantly (other than through ill health) were crosscountry skiing (despite eating 5000 calories or more per day) and during Finals.
Thinking definitely burns calories. Though, I'm not sure how much more it is than when the brain is "resting" (your brain is always working, and most of what it does is not conscious).
I also feel harrased after the long day at school or after taking an exam . But , I bet that this is just mental strain. you are emotionally exhausted and you also have an urgent desire to rest in some quiet room where no problems are confronted and no solutions are searched for . however , I will be pleased to find out that , on the contrary,the process of thinkingg does really burns calories .
I think it has something to do with what you are thinking.