Most existing algorithms have applied the same weight to all nutrients in the scoring. Few systems have incorporated weighting, probably because the evidence base for these decisions has not been strong. However, the NuVal system applies proprietary weighting to nutrients based on the prevalence of health conditions associated with specific nutrients, the severity of the condition, and the relative strength of the association (Katz, 2007). Prevalence measures were derived from NHANES. The severity and relative strength determinations were made based on epidemiological evidence and interpretation of that evidence by consensus of the expert panel that designed the algorithm. A simpler approach could be used, such as applying a greater weight to the negative nutrients than the positive nutrients. This approach was used in the design of the HEI, whereby calories from solid fats, added sugars, and alcohol were weighted twice as heavily as other components, and saturated fat was also included as a separate component (Guenther, Reedy, Krebs-Smith, Reeve, & Basiotis, 2007). The determination of weighting factors using other methods is an important topic for future research.