How Many Calories Can the Brain Burn by Thinking?
In 1984, the World Chess Championship was called off abruptly, due to the worryingly emaciated frame of Anatoly Karpov, an elite Russian player who was competing for the title. Over the preceding five months and dozens of matches, Karpov had lost 22 lbs. (10 kilograms), and competition organizers feared for his health.
Karpov’s wasn’t alone in experiencing the extreme physical effects of the game. While no chess competitor has experienced such profound weight loss since then, elite players can reportedly burn up to an estimated 6,000 calories in one day — all without moving from their seats, ESPN reported.
Is the brain responsible for this massive uptake of energy? And does that mean that thinking harder is a simple route to losing weight? To delve into that question, we first need to understand how much energy is used up by a regular, non-chess-obsessed brain.
When the body is at rest — not engaged in any activity besides the basics of breathing, digesting and keeping itself warm — we know that the brain uses up a startling 20% to 25% of the body’s overall energy, mainly in the form of glucose.
That translates to 350 or 450 calories per day for the average woman or man, respectively. During childhood, the brain is even more ravenous. “In the average 5- to 6-year-old, the brain can use upwards of 60% of the body’s energy,” said Doug Boyer, an associate professor of evolutionary anthropology from Duke University. Boyer researches anatomical and physiological changes associated with primate origins.
This glucose-guzzling habit actually makes the brain the most energy-expensive organ in the body, and yet it makes up only 2% of the body’s weight, overall.
Most of the energy used up by the brain is devoted to enabling neurons in the brain to communicate with each other, via chemical signals transmitted across cell structures called synapses, said Harrington. “A lot of the energy goes towards firing a synapse. That involves a lot of transportation of ions across membranes, which is thought to be one of the most expensive processes in the brain.”
In addition, the brain never really rests, she explained; when we sleep, it still requires fuel to keep firing off signals between cells to maintain our body’s functions. What’s more, servicing the brain are fleets of cells that exist to channel nourishment toward neurons. And these cells also need their share of the body’s glucose in order to survive and continue doing their job. The huge resources devoted to building a brain also help to explain why during periods of intensive development, when we’re 5 or 6 years old, our brains scarf up almost three times the amount of energy that our adult brains need.
Here’s the kicker
Since the brain is such a big energy-guzzler, does that mean that the more we put the brain to work, the more energy it’ll slurp up — and the more calories we’ll burn?
The answer is yes, for cognitively difficult tasks. What counts as a “difficult”‘ mental task varies between individuals. But generally, it could be described as something that “the brain cannot solve easily using previously learned routines, or tasks that change the conditions continuously,” according to Claude Messier, a professor of psychology and neuroscience at the University of Ottawa in Canada, who has studied cognition, diabetes and brain metabolism. Such activities might include learning to play a musical instrument or plotting innovative moves during an intense game of chess.
“When you train to learn something new, your brain adapts to increase energy transfer in whatever [brain] regions are activated by the training,” said Messier. Over time, as we become more skilled at performing a particular task, the brain no longer has to work as hard to accomplish it, and so doing that task will eventually require less energy, Messier explained.
And there you have it. The reason why so many lard-arses vote for the left.