There's actually a great way to track that - look at the cost of a Chipotle burrito in different cities. The price for a burrito in San Francisco went up with perfect correlation when the wage increased in San Francisco. The reason it's particularly useful for Chipotle is because they are entirely corporate owned, which means there are no franchise owners distorting the data (or rather, franchises are independently owned and many are not well run, and restaurants with lower prices would be used as data points to justify the wage increase when that restaurant may in fact be failing).

Not too long ago it was part of my job to analyze the minimum wage hike and how it will effect fast food restaurants. Like most things in the real world, the nitty gritty details are complicated. The gist of it is that fast food restaurants in the United States are going to become even less profitable as the minimum wage increases. And in an industry where it's considered great if your margins are 5%, that can be pretty bad.