If you adjusted for race the gap would be significantly less. Also, California just seems to attract fit people. I noticed this when I took our kids to Lego Land in Carlsbad. Took a walk along the beach, and 100% of the people looked healthy and fit. In the South, you have a lot of folks whose exercise consists of climbing up a tree stand.
The beach people in Carlsbad are well-educated, high income people, they take care of their physical appearance and health.
The coast and especially the more expensive coast, is not representative of all of California, visit a grocery store on the coast and look at the wives, versus the wives at inland grocery stores.