This invention relates to heterophasic copolymers of propylene and an alpha olefin comonomer having a high fill phase content (≧15%), and heterophasic polymerization processes using a single site catalyst system with a support having high average particle size (PS≧30 μm), high surface area (SA≧400 m2/g), low pore volume (PV≦2 mL/g), and a mean pore diameter range of 1≦PD≦20 nm.