A food delivery system for use in a hospital or other institution is disclosed. The system comprises a portable cart having compartments for receiving stackable food trays therein. A platform operated by a lever mechanism is provided on the cart for stacking the trays in intimate contact with each other to form a vertical thermal column for retaining heat or cold during transporting of the trays. During loading and unloading the platform is lowered to permit the trays to rest on ''''L'''' brackets which are spaced such that each tray is out of contact with every other tray.