Increasing knowledge of how the diet composition and socio-demographics of vegetarians have changed over time can help us to understand changes in the health and nutrition status of vegetarians. The objective of this study is to examine the shift in diet composition of self-perceived vegetarians over the past forty years, as well as the demographic and socioeconomic characteristics of being a self-perceived vegetarian in 1977 and in 2010. Using OLS regression, the probability of being a vegetarian by key demographic characteristics was examined for 1977- 78 and 2007-2010. Consumption of key nutrients, including total daily kilocalories, ounces of meat, added sugars, whole grains, servings of fruits and vegetables were compared by vegetarian status in 1977-78 and 2007-2010. In doing so, the final goal is to compare the overarching picture of the diet of vegetarians over the past forty years in the United States.