This chapter investigates estimated energy equations essential to individuals’ factors that need to be considered before use. Due to the large number of possible equations, practitioners will need to determine which equation might be most appropriate. Additionally, for certain populations, estimation equations may under- or overestimate energy/calories needed due to the limited accuracy for individuals who are not within the “average” healthy population. Therefore, assessing patient-specific factors and understanding the equations strength to account for body composition, ethnicity, and possible disease states will increase the effectiveness of the equation. The more individual data points and combining the strength of an equation will allow for a more informed decision-making process for the nutritional assessment.