Is there anyway that you can pivot your data?...so that "Food Type" is a dimension, and not have a measure for each type (Tableau has this functionality built in on the Connect to Data screen). This would let Tableau re-sort the order, and you'd only need one calculation.
If that means nothing to you! let me know and I'll go into a bit more detail and work up an example
Hi Simon, thanks for getting back to me so quickly! Unfortunately, the way my actual dataset is structured, each food has to be a separate variable and each rate has to be a measure. Any ideas?