According to research from Northwestern Medicine, post-menopausal women who are overweight can have a decline in memory that is in direct correlation to their extra pounds.
"The study of 8,745 cognitively normal, post-menopausal women ages 65 to 79 from the Women's Health Initiative hormone trials is the first in the United States to link obesity to poorer memory and brain function in women and to identify the body-shape connection."
On a 100-point memory test, every increase of a single point in a subject's BMI also coincided with a drop by one point in her memory score.
Pear-shaped women may have more cognitive dysfunction than apple-shaped women, because of where the extra pounds are distributed. The kind of fat carried by pear-shaped women release cytokines. Cytokines are hormones that cause inflammation and may affect cognition.
The study could be useful in identifying which women may be at risk for cognitive dysfunction, according to their waist-to-hip ratios.
http://www.sciencedaily.com/releases/2010/07/100714112832.htm