In cognitively healthy older adults, reduced cortical thickness in the frontal and temporal lobes is associated with poorer performance in recognition memory and delayed recall of visual information, and smaller hippocampal volume is associated with worse performance in recognition memory, delayed visual recall, and verbal learning.

Excess body fat causes the body to become less responsive to insulin, which reduces the brain's ability to use sugar for energy. Without enough energy, brain cells in areas responsible for memory start to shrink and lose connections. This shrinkage in the front and side parts of the brain and the memory center directly weakens the brain's ability to store and recall visual and verbal information.