A rethermalization system for rethermalizing food includes (a) a food service tray having a hot dish through-opening and the through-opening having a through-opening top edge, (b) a rethermalization cart including a cart frame, a plurality of heating pads supported within the cart frame, and a plurality of vertically spaced tray supports attached to the cart frame for supporting the food service tray at a plurality of alternative vertically spaced shelf locations, and in a tray support position such that the hot dish through-opening is disposed above one of the heating pads, and (c) a food service dish positionable in the hot dish through-opening of the food service tray. The food service dish has a bottom surface for allowing heat transfer to occur from the heating pad to food in the food service dish with the tray in the tray support position, The food service dish is positionable in a heating position when the tray is in the tray support position such that the bottom surface of the food service dish is supported by the heating pad and an upper lip of the food service dish is slightly raised and out of contact with hot dish through-opening edge. This prevents heat transfer between the food service dish and the food service tray during heating of the food. The food service dish is also positionable in a serving position when the tray is supported on a planar surface such that the food service dish is supported by the contact of the upper lip with the hot dish through-opening top edge. This causes the generally vertical wall to be closely positioned adjacent to the hot dish through-opening in order to prevent excessive movement of the food service dish within the through-opening while the rethermalized food in the food service dish is being consumed.