Why does my feet get numb when i sit in bad positions?i am currently over weight is this the cause or does it have anything to do with bad circulation

Doubtful: Numbness is usually nerve mediated. Sitting in certain positions will compress a nerve leading to neuropraxia, a temporary numbness. Dont sit in those positions and lose some weight.

No: More then likely a nerve is getting compressed or compromised in those positions leading to tingling in your feet. If it continues or gets worse, see your doctor.

Unlikely vascular: Easy to check pulses and pressures to be sure it is not vascular a spinal- disc, or local nerve pressure with the weight seem more likely as a starting point.

Circulation: if your symptoms only occur with sitting its not a circulatory disturbance but more likely low back problems with nerve compression