Science
Our gray matter requires a lot of energy, which means we need food to fuel our brains. But why, in this case, don't we lose weight just by sitting at the table.
So how many calories can you actually burn using your brain alone?
To understand how many calories we're burning at any given time, it's worth understanding the costs of physical activity.
Walking burns about 4 calories per minute, which is more than 1,300 calories a day that most people need to survive.
More intense physical activity, such as kickboxing, burns 10 calories per minute.
How many calories are burned during mental work
The brain, on its own, burns only one-tenth of a calorie per minute. In percentage terms, this is quite high for tissue that is at rest.
When we're actively thinking about something, the brain can start burning up to 1.5 calories per minute.
Considering that this is an inert mass, which is only 2 percent of a person's weight, this is quite an impressive figure.
When we think, millions of neurons trigger messages to each other and to different tissues in our bodies.
These neurons need fuel and consume about 75 percent of blood sugar from the liver and 20 percent of all our body's used oxygen.
This is how neurons feed: special cells suck glucose out of the blood and turn it into a form that neurons can consume. Neurons then use this to produce a neurotransmitter, a nerve impulse transmitter, and eventually to create a conscious thought.
The more energy an area of the brain needs, the more glucose this part of the brain breaks down.
If you think hard and struggle with your thoughts, neurons in the frontal lobes of the brain will burn more glucose. Unfortunately we don't use this part all the time.
Although the brain takes about 20 percent or 300 calories from the 1,300 calories in our resting body, experts estimate that active thought can increase the number of calories burned by the brain, by 20-50 calories per day.
But we don't usually do this kind of activity for long.
What conclusion can we draw from all this? An enhanced thought process is not the best way to lose weight and therefore it is worth exercising.