Lots of things are contributing to fast food going up. Gas prices are affecting discretionary spending. People are not eating out as much. Many people have not returned to the workforce and or are now shut INS and maybe get groceries but dramatically reduced outside activities. The work from home crowd is not spending on eating out as before. Interest rates keep making it more difficult to acquire financing for short or long term funding. Trades have been busy and quadrupled their rates to be more selective in their customers. Staffing is difficult at best. Regulations have raised pay along with low available workforce having also raised pay. Groceries cost fast food eateries the same or more as you purchase if counting the high cost of delivery to the restaurant. The biggest contribution to restaurant inflation is the rapid adoption of food delivery which charge an average of almost half the cost of the order. These delivery apps used to be a small percentage of the business and could be absorbed. This is no longer the case. But restaurants are unwilling to increase delivery app prices and instead are raising prices for everything ( in person, Togo, and delivery apps).

This may not be stagflation like the 70s but everything that has been done is creating a no win situation.