Container base cup having reduced heat gain

1. Field of the Invention Base cup for receiving a container body bottom and for reducing heat gain to fluid contents in the container body. A passive base cup is made of foam and has a reflective layer on a majority of the outer surface thereof, or made of plastic, with an outer reflective layer, and optionally a foam layer. An active base cup serves to actively cool the fluid in the container, by including a compartment therein with a fluid that can be frozen. Again, a reflective layer and an optional foam layer extend over a majority of the outer surface of the cup. The reflective layer materials have a density different than the cup materials to facilitate recycling.