According to a recent research, over weight has an impact on intelligence and this impact is dubbed the "Homer Simpson effect".

This 5-year study has established that people with higher body mass index (BMI) scored lower on average in cognitive tests within a sample. This research was published in Neurology, the journal of the American Academy of Neurology.

In the meantime, another study conducted by Scot researchers, was published in the same journal, according to which, there is an association between physical and mental fitness.

Dr Maxime Cournot, of Toulouse University Hospital in France, led the research on the impact of weight on brainpower. 2223 healthy people, aged 32 - 62 were included in this study. They had taken up 4 cognitive tests like word learning in 1996 and again in 2001.

The results of the word memory test revealed that an average of 9 out of 16 words were remembered by people with a BMI of 20, which is in the healthy range, whereas, an average of only 7 words were remembered by people in with the BMI of 30, which is in the obese range.

"While those whose BMI changed over the five years did not appear to see any change in their cognitive function, those who started out with a higher BMI did appear to show higher levels of cognitive decline", Dr Cournot said. "The findings may be due to a host of factors including the thickening and hardening of cerebral vessels because of obesity or possibly the development of insulin resistance," he said.