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.
Humans aren’t unique in this regard. Together with Duke University evolutionary anthropology graduate student Arianna Harrington, who studies energy usage in mammal brains, Boyer conducted research revealing that very small mammals such as the tiny tree shrew and the minuscule pygmy marmoset devote just as much of their body energy to the brain as humans do.
Boyer believes the reason is that despite brains being lightweight, human brains — and the similarly glucose-hungry brains in tree shrews and marmosets — are large relative to the rest of the body. “If you have a really big brain relative to your body size, then it’s probably going to be more expensive metabolically,” Boyer told Live Science. … [ ]