Answer:
First of all: Heat energy is transferred from higher to lower level.
Normally,a room temperature is about 25°C–27°C. Hot food has temperature higher than that, and (cold) drinks have temperature lower than that. So, heat is transferred from/to the atmosphere to maintain heat levels at the Normal temperature and pressure.
When kept in open, heat transfers from the food (higher level of heat) to atmosphere (lower level), decreasing it's temperature, i.e., making it cold.
Likewise, in case of (cold) drinks, heat is transferred to the drink (lower level of heat) from the atmosphere (higher level), hence making it warmer.