This review outlines a role for saccharides in the brain and offers predictions about how saccharides might influence cognitive performance. Animal studies provide a biological mechanism by which saccharides affect brain function and, in turn, cognition. Furthermore, recent intervention studies suggest that saccharides may have an effect on the cognitive performance of humans. Because the effects of saccharide supplementation on cognitive performance are likely to be subtle, future investigations will face various methodological challenges, not the least of which is the need for sensitive outcome measures.