Another option for a scoring system is based on thresholds (e.g., FSA XYW model/Ofcom). This type of system uses a cutoff or threshold nutrient level to assign points for negative and positive attributes, subtracts the positives from the negatives to get a continuous score, and then categorizes or dichotomizes the score. For the XYW model/Ofcom, there are a series of 11 thresholds (0 to 10 points) for the negative nutrients that include energy, saturated fat, total sugar, and sodium, and there are 6 thresholds for positive nutrients/components that include the percentage of fruits, vegetables and nuts, fiber, and protein. This algorithm is unique in that it contains food groups in addition to nutrients as a positive component. However, the selection of thresholds to assign points is not necessarily clearly justified.
Using an overall score employing thresholds to assign points, potential modifications to test include the following:
- unit basis (e.g., per 100 kcal or per RACC serving instead of per 100 g)
- nutrients (e.g., include a fat-quality indicator such as saturated fat as a percentage of total fat; replace total sugar with added sugar in the model; remove energy from the model; or include vitamins or minerals such as vitamin D, iron, potassium, or calcium)
- food groups (e.g., with or without percentage of fruits, vegetables, and nuts; include low-fat dairy)
- weighting (e.g., assigning more weight to negative nutrients as positive nutrients)
- conversion of overall score to categorical rankings (e.g., categorize final score into two [healthy or not] or three [low, medium, high] categories using one set of cutoffs or food category-specific cutoffs)