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.
The "Homer Simpson effect" is the nickname given to this phenomenon by some media in North America.
The other study establishing a link between physical and mental fitness, conducted by Scot researchers included 460 people. They had participated in a mental health survey in 1932 at the age of 11 and again in 2000 at the age of 79.
Report author Professor Ian Deary, of Edinburgh University, said: "Fitness contributes to better cognitive ability in old age.
"Thus, two people starting out with the same IQ at age 11, the fitter person at age 79 will, on average, have better cognitive function."