We all know that losing weight is merely a matter of exerting sufficient will power and self control, right? And that any failure to do so is our own moral failing? Well, quel surprise, perhaps not:

Focusing attention and using one part of your brain against another part, that takes significant energy. The brain is already our most energy-intensive organ, so adding the demands of “self control” on top of that is likely to have presented some adaptive issues in the past. Put differently, it’s unlikely to expect that we’ve evolved to be able to maintain self control over extremely long periods of time (say, months), simply because such problems rarely presented themselves in the past (there were few adaptive benefits) and because the energetic costs of doing so would have been quite high.

And as for losing weight?

Diets are often marked by periods of effortful weight loss, followed by a slide back, where weight is regained. That pattern is not simply a matter of mind over matter, of willpower so we can match a cultural and cognitive ideal. It’s hard for people to maintain sustained mental efforts, it costs energy, and there’s little evolutionary reason to expect everybody’s brains to suddenly begin cooperating with what our culture tells us we should be able to do.

I’m way out of my depth here, but if focusing attention towards will power and self control uses a significant amount of energy, wouldn’t it follow that a human being needs to take in more calories to make up for the additional energy expenditure that it costs to diet? Now put that in your Points (TM!) slider and calculate it.

From Glucose, Self Control and Evolution, posted at Neuroanthropology. Thanks to my husband, who reads blogs about neuroanthropology so I don’t have to.