Evolutionarily, it makes sense. Ever feel hungry? It’s caused by a hormone named ghrelin. Apparently it’s multi-use, as Clare Wilson reports in NewScientist (29 April 2017):
But there is also evidence that ghrelin can enhance cognition. Animals fed reduced-calorie diets have better mental abilities. Injecting ghrelin into mice improves their performance in learning and memory tests, and seems to boost the number of connections in their brains.
Now Jeffrey Davies at Swansea University, UK, and his team have found further evidence that ghrelin can stimulate brain cells to divide and multiply, a process called neurogenesis. When they added the hormone to mouse brain cells grown in a dish, it switched on a gene known to trigger neurogenesis.
So if your immediate problem is a lack of food, you get sharper; but once you’ve satisfied that, you go into drowse mode. And then the tiger takes you.
So far, it’s not clear if fasting helps protect the brain, but it’s an interesting thought. Personally, I find “hunger headaches” to be blinding.
