Is it permissible to take money designated for food and save it without spending it, knowing that the employer provides it in addition to the salary?

The amount given by the employer for work and food—if stipulated in the contract—is the property of the worker, who may dispose of it as he wishes, for the Prophet, peace and blessings be upon him, said: "Muslims are bound by their conditions in what is lawful." However, if the food allowance is a gift not stipulated, it is preferable to seek the employer's permission to dispose of it for purposes other than purchasing food, unless custom dictates that the worker may dispose of it as he wishes. For what is recognized by custom is as binding as what is stipulated by condition.