Not sure about the law in the US, but I suspect serving free food could be a way to pay employees tax free? That is, the costs for the food will be losses for the company, but not taxed as earnings for the employees?

I think in Germany at least there is a limit as to how much a company is allowed to pay for food per employee, but I am not sure if it would also apply if food was completely free (I only know models where the company subsidizes the food).