New research in the journal Neurology is adding to a growing body of evidence that overweight and obese adults are more likely to develop dementias such as Alzheimer's disease.
The on-going study is following more than 6,400 adults between the ages of 39 to 63.
Obesity was found to have an increasingly negative impact on performance in memory and reasoning tests.
Diseases of the blood vessels supplying the brain, and the release of proteins by fatty tissue, have been suggested by scientists as possible causes.
