A good food blogger focusing on the US/High GDP audience can get CPMs from $1-4[2]. Where it gets interesting are the RPM numbers. If you can manage multiple ad networks, execute 100% fill rates, bid between networks and become a preferred partner, you can rake up to $12-15in RPM [3]. Here’s more of multiple revenue sources for a successful blog [4]
Caveat: Things take off once you cross around 700—800K US traffic. Until then it can be frustrating.
[1]: https://alittlebitofspice.com/
[2]: http://d.pr/i/bIBobD
[3]: http://d.pr/i/Qvk1M
[4]: http://d.pr/i/dEqpvA