Although it makes up only 2% of body weight, the brain uses approximately 75% of blood glucose, making it by far the most metabolically expensive organ in the human body brain (Dunbar, 1998; Kahn, 2005). Glucose (the main type of sugar in the blood) is the main source of energy for the brain and the rest of the body. When glucose levels are high, excess glucose is converted and stored as glycogen, which can later be metabolically converted back to glucose and used for energy. The energetic cost is especially high for mental tasks that recruit the “central manager” or areas of the brain that regulate cognitive and emotional control. These tasks reduce blood glucose levels at higher rates than other mental tasks that do not recruit the executive (Galliot & Baumeister, 2007). Furthermore, many tasks that would appear to require self-regulation and executive function suffer when glucose is depleted and may show improved performance if glucose levels are restored. Such tasks include avoiding prejudicial or stereotype-driven behaviors (Galliot et al., 2009), being willing to help strangers (DeWall, Baumeister, Galliot, & Maner, 2008), attention monitoring performance in a dual-task situation ( Scholey, Sunram-Lea, Greer, Elliot, & Kennedy, 2009) memory (Meikle, Riby & Stollery, 2004), complex decision-making processes (Masicampo & Baumeister, 2008); and persistence on difficult tasks (see Galliot, 2008 for a review). Most previous studies have used social cognition procedures that intuitively appear to require executive processing, but which do not have a direct, controlled comparison between executive and nonexecutive conditions. Therefore, it is unclear whether glucose has its main effects on the regulation and value of word imagery on human memory. Behavioral Neuroscience, 113, 431-438. Scholey, A. B., Sunram-Lea, S. I., Greer, J., Elliot, J., & Kennedy, D. O. (2009). Glucose administration before a divided attention task improves tracking performance but not word recognition: Evidence against differential memory enhancement? Psychopharmacology, 202, 549-558. Scholey, A. B., Sunram-Lea, S. I., Greer, J., Elliot, J., & Kennedy, D. O. (2009). Memory enhancement by glucose depends on initial thirst. Appetite, 53, 426-429.Scholey, A. B., Harper, S., Kennedy, D. O. (2001). Cognitive demand and glycemia. Physiology and Behavior, 73, 585-592. Sunram-Lea, S. I., Foster, J. K., Durlach, P., & Perez, C. (2002). The effect of retrograde and anterograde glucose administration on memory performance in healthy young adults. Behavioral brain research, 134, 505-516.