We can’t really give you any advice on how to be more intelligent—hell, scientists even have a hard time defining what exactly intelligence is—but we can tell you how you might improve your working memory and clarify your thinking: lose some weight.
A study published in the Journal of Neuroscience has found that obese mice had reduced neural plasticity compared to normal sized mice, due to the presence of a chemical called interleukin 1. Normally, it shouldn’t be able to pass the blood-brain barrier, but in the obese mice, it did, causing inflammation in the hippocampus, which is responsible for memory and learning.
Researchers then put the mice through a series of cognitive tests. One tests measured novel object recognition—basically, mice really like new things, so to measure how well they remember something, you put two objects in their cage, one new and one they’ve seen before. Normally, mice spend more than three quarters of their time inspecting the new object, usually after they’ve worked out that the old object is familiar to them. The normally sized mice did this—but the obese mice didn’t. Rather, they spent about half their time on each object, because they’d forgotten that they’d seen the old object before.
Just to make sure that it was the extra fat cells mucking things up, scientists then had their mice lose the weight (with mini-liposuctions), and then repeat the tests. After losing weight, the mice did as well as their normally sized brethren.