Specify the NoData pixel from 255 to a lower value pixel value

I have a series of raster files (tif) that extracted using a particular shapefile.

However, the output files became much larger (from 2 MB to 200MB). The NoData is now equivalent to pixel value of 255 instead of 0 (maybe this is the reason). Is there a way to specify it through this code?

 import arcpy
 from arcpy import env
 from arcpy.sa import *
 arcpy.CheckOutExtension("Spatial")
 env.overwriteOutput = True

 #Set the current workspace
 env.workspace = ("C:\Users\Brent\Documents\JO_GIS_Analyst and PA")

 #This is for extracting the forest areas of hansen percent treecover
 for raster in arcpy.ListRasters("lossyear*", "TIF"):
     print raster #checking the presence of raster
     outputRasterExtractbyMask = ExtractByMask(raster, "NAMRIA.shp")
     outputRasterExtractbyMask_Name = "forest_only"+raster
     outputRasterExtractbyMask.save(outputRasterExtractbyMask_Name)

Thank you!