Thinking could lead to weight gainEver wondered how many calories you burn thinking hard? Well I have, so I consulted my good friend Google for some answers. I did not like what found: Not only does it burn pitifully few calories, but thinking might actually make you fat.

In a Canadian study published in Psychosomatic Medicine, scientists had students either relax, take memory and attention tests or memorize text for 45 minutes at a time. They burned a paltry 3 more calories using their minds than relaxing — enough to burn a small stalk of celery, or one-and-a-half M&Ms.

Then, the students were treated to an all-you-can-eat buffet (where do I sign up?) And get this — they ate 203 more calories after memorizing text than after relaxing, and a whopping 253 extra calories after taking tests. Hmmm, helps explain why I can’t stop snacking during my writing days.

Why the post-thinking pig-outs? Researchers tested blood samples, and found that mental activity causes fluctuations in blood glucose and insulin, making you feel hungrier. It makes sense, because glucose is your brain’s main fuel source — that’s why low-carb diets can impair your brain function (your body gets its glucose from carbohydrates in food).

But wait, it gets even worse. Not only does thinking make you hungrier, but most people do their thinking sitting behind a desk, where they aren’t burning very many calories. Said the study authors, “caloric overcompensation following intellectual work, combined with the fact that we are less physically active when doing intellectual tasks, could contribute to the obesity epidemic.” Crap.

But Will You Really Get Fat if You Think A Lot?

Well, I’m certainly not going to stop thinking (I’d have to change the name of my blog, for one thing). This was a very small study with only 14 participants — and I’ve never seen any epidemiological evidence that brainy folks are any fatter than than the drones of society.

Even if thinking does make people splurge at lunchtime, the solution seems pretty simple: exercise more. Research shows that exercise keeps your mind sharp anyway, so it’s great for thinkers. Hey, I run every other day and haven’t gotten fat yet, so at least one case study says it works. Though knowing the science, maybe now I’ll tack on an extra mile on my heaviest brainwork days.