Poor Glucose Control harms region of the brain involved in memory formation

Poor glucose control, or excessive consumption of sugar, can lead to disastrous ramifications for a brain region that helps form long-term memories, probably by reducing insulin sensitivity and causing poor mitochondrial function.

The Dentate Gyrus, which is a region of the hippocampal formation, helps the brain store memories. The Dentate Gyrus is also a brain region which creates new neurons through a delicate process called neurogenesis, in which progenitor stem cells specialize into fully functional neurons. Exercise has been shown in studies to boost neurotrophic factors which help form new brain cells in this region of the brain.

http://www.nytimes.com/2009/01/01/health/31memory.html

Conscientiousness is a personality trait that is associated with the Big Five personality model. It is characterized by exceptional organizational skills, cautiousness, neatness, rigidness, detail-orientedness, and scrupulosity. People who score high on conscientiousness tend to be neat, prudent, and organized in their daily lives and are less likely to engage in risky behaviors which may jeopardize their ultimate fruition and wellbeing. People who score higher on this trait are admittedly susceptible to developing OCD or OCPD. However, studies demonstrate the positive role that conscientiousness may play on maximizing happiness throughout one's life. (1) Another study suggests that conscientiousness is associated with a reduced risk of developing dementia because of its positive effect on slowing down brain atrophy that is associated with normal aging. (2) The Big Five Trait associated with higher rates of dementia and brain atrophy is neuroticism. (3) (4)