>>420897257
Bluetooth being blocked by your body is pretty normal and more or less the biggest flaw of the technology.
Put the dongles to a better place and it'll work out fine. If you put it directly on your PC, it'll cause interference as well. Get 20-30cm of cable and put it somewhere else.
I'm not super thin, but not fat and I also have no problems with the signal going "around me".
[spoiler]Sorry for assuming. Had low blood sugar.[/spoiler]