According the usual standards, body mass index (BMI) = body weight (kg) /the squared of height’ (in meters), its normal weigh is between 18.5 to 25, 25--29 is overweight, 30 and above is obese.
According the reported of British "Sunday Telegraph" on the 15th, the French scientists do a intelligence tests about a period of 5 years for 2200 between 32 years and 62 years. The results showed, the one whose body mass index below 20 will remember 56% vocabulary, but the one whose body mass index above 30 will remember 44% words.
Scientists also found that people who gained weight during the study ability reduced faster. In the end of the 5-year test results showed that weight gain can only recall the 37.5% vocabulary, but the one whose body weight remained normal the memory is without any change..
The leader of this study, Maxim • Cournaud (France Toulouse University Hospital), thought the hormones by fat secrete have some devastating effects for the cerebellum, and make the brain function decline. In addition, obesity also make the make the blood vessel wall thicken, hardening of blood vessels
  The research results of French scientists have been published in the latest Magazine of United States, called "Neurology".

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