As mentioned above, the restaurant has to prepare a large amount of different foods because "In every buffet there is a certain tension: will there be enough food?" Will I have to wait hours to get some?...' (Cullen 1997, p. 129-130) Therefore, the cost of food increases. As the cost of food rises, labor remains stable and the contribution margin shrinks; consequently profitability will be reduced. Because the manager not only increases the cost of food, but also reduces sales