Most likely when you log into your account, the ATL-NRT leg will say "Not Upgrade Eligible". My work associate on same project is even having trouble with the GUCs on this route depending on days. (I've been on the MSP-NRT route with no luck)

Food wise after passport control, next to McDonald's there is the Tatsu udon noodle shop, but food after passport control is meager compared to before security. Lots of options.