A junk food tax that excludes meat?

A new study proposes a tax on unhealthy foods that would exclude meats and many dairy products. If the point is to try to take cost pressure off public health, I would have thought a tax on meat and dairy would be a priority.

Article: https://www.theguardian.com/australia-news/2017/feb/15/australia-would-save-34bn-if-junk-food-taxed-and-fresh-food-subsidised-says-study

Study: http://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.1002232#sec008