Cancer incidence and mortality are growing in the US; however, the dietary contribution to the increase in cancer cases has not yet been elucidated. The Insulin-like Growth Factor-I (IGF-I) pathway is a hormonal pathway that connects diet and cancer. Nutritional studies have shown that IGF-I levels are dependent on nutrient consumption in a persons' diet. The IGF-I protein is the most reliable nutritional biomarker in malnourishment and fasting. Furthermore, the IGF-I levels in blood depend on nutrient intake characteristics and the amount of nutrients consumed. IGF-I protein influences several metabolic processes, including normal and malignant cell growth. Previous studies have shown that increased IGF-I levels are related to a higher risk of breast, prostate, and colorectal cancer. Although efforts have been made to clarify the role of dietary components in cancer, researchers have failed to determine with accuracy its impact on cancer risk. Furthermore, prevention strategies to improve current cancer risk have failed, possibly due to inappropriate strategies to inform the public. This dissertation has the following objectives: to provide an overview of previous research in the form of a literature review to identify current research gaps; to investigate the association between a previous history of cancer and adherence to dietary patterns in the US; to examine the relationship between dietary patterns and IGF-I levels in the blood; and to investigate the association between dietary patterns, total mortality, and cancer mortality.