The relationship between nutrition and behavior is bi-directional in nature, with nutritional factors capable of affecting activity and disposition and behavior impacting diet and food intake. This book reviews these links, starting with their complex, neurobiological basis such as in the case of folate deficiency and cognitive decline. It also illustrates how behavior may determine nutritional choices or status through peer modeling and poor dietary habits. Micronutrients and eating disorders are then critically addressed with a review of current research methods and results before extra-nutritional influencers on behavior such as caffeine, herbal supplements, and alcohol are discussed in the final section.