Brain A 2002 study conducted at the University of California, Los Angeles, stumbled upon a frightening link between excessive sugar consumption and brain health. The study found that diets high in sugar affected the neuronal and behavioral plasticity associated with a chemical known as brain-derived neurotrophic factor (BDNF). This leads to decreased function in the ability to efficiently form new memories and store new information. Other research has also linked low levels of this chemical to depression and dementia.