It is interesting that high food prices effects convenience stores (CVS) and restaurants differently. High prices hurt restaurants and the empty tables you might have noticed attest to that. If you still are not convinced, Denny's has just announced that it will be reducing some prices which is always a sign of poor sales.
At the same time, all CVS chains are reporting around 11 percent increased sales over last year. Prices at CVS are not cheap, but they are cheaper than at restaurants. People appear to be making that calculation.