gdal_calc.py outputs huge files

I think this is a general enough question to apply to more than just gdal_calc, but perhaps not. When I run

gdal_calc.py -A map.tif --outfile=deforestation_00-10.tif --NoDataValue=0 --calc="A >= 7"

on a 38000 x 38000 62.5MB tif, the output is 1.37GB (and still 38000 x 38000). I feel like i’m probably missing something big here, i.e. how tif data is stored. [the same thing happens when I run it using the raster calculator in qGIS] Thanks in advance.

Bonus points–anyone know how to include and/or logic in the –calc=”…” in order to evaluate the following: (map@1 >= 7 AND map@1 <= 9) OR ((map@1 >= 10 AND map@1 <= 12) * 2)