This depends on the car, however in general.
If you use the heat alone to fog the windows: Yes but only slight.
You will create a slight load on the engine due to increased electrical demand from the blower fans on the Alternator ~probably sub sub 100W and likely un-noticable.
If you use the heat with A/C activated:
Yes but how much depends on the car design.
Depending on the Car and A/C Design, some may not activate the A/C and would be the same as above.
However as described by @sweber most will run the air first through the A/C to help remove moisture from the air, then through the heater to help evaporate the fog from the glass. In this case, it because the A/C is in use, there will be an increased load on the engine by the A/C Compressor.
This can be quite significant (up to 10HP+ in some cars).
So yes in your case, you will likely see an increase in parasitic load on the engine, causing slight fuel economy decrease and slight loss of power.