A waiter should serve food to guests from the left side with the left hand. This is because it is the standard etiquette in the food service industry. It is believed to have originated from the French court where it was customary for servers to serve from the left side of guests. This is also consistent with the sequence of service in a multi-course meal, where food is served and cleared from the left side. Serving with the left hand also allows the waiter to hold and adjust the plate with the right hand if needed.