Does being smart make you thin?

No.10900088 ViewReplyOriginalReport
Or more specifically, being an extremely active thinker?
Humans are exceptional in their brains using 20% of their energy, but that 20% figure presumably varies by quite a margin, although it's not exactly something that's easy to measure (How did people get that 20% figure anyway?).

With weight management, tiny differences in energy usage and consumption really matter; a slight excess can add many kilograms over the course of years, and vice-versa.
So if the brain were to use 50% more or less energy, that would change your energy consumption by a whopping 10%; which really counts if the difference between energy consumption and usage is rarely larger than that.

There does seem to be plenty of stupid fat people who gain a kilogram if they even look at a chocolate bar and brainy thin people who consume calories like crazy.