Researchers have found that fat people have smaller brains than skinny people, there is no argument about this measurements have proven it, but argument could be mounted as to whether being fat causes brain cell loss or whether brain cell loss causes you to get fat. Mounting evidence and a pretty good hypothesis would suggest that getting fat causes brain shrinkage.Type 2 Diabetes is associated with being fat as is high insulin levels, but after accounting for this being fat was still associated with brain shrinkage.
A Body Mass Index above the desired parameters increases your rate of blood vessel clogging and a lack of blood supply to the brain is a known cause of brain shrinkage, and this is why hard exercise such as jogging improves brain function by increasing the blood flow to the brain.
http://www.newscientist.com/article/mg2032...nking-brains.ht
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