Sugar can cause an increase in delat, alpha and theta brain waves, which can alter the mind's ability to think clearly. Sugar can cause depression. Sugar can increase insulin responses in those consuming high-sugar diets compared to low sugar diets. Sugar increases bacterial fermentation in the colon. Sugar can cause hormonal imbalance.
Sugar can increase blood platelet adhesiveness which increases risk of blood clots.
Sugar increases the risk of Alzheimer Disease. A. Sanchez, et al. F. Couizy, C. Keen, M.E.Gershwin, and F.P. Mareschi. Nutritional Implications of the Interaction between Minerals. D. Behar, J. Rapoport, Berg C., Adams, and M. Cornblat.