Nope. Everything has to be saved in the game, every object you move around, every inch of map you uncover... everything. That's why it takes up so much space.
I think it's about 20mb per save.
But here's a tip: For older savegames, zip them so they only take up 4mb per save. You can find your saves in the savegames directory. Just don't zip the "BD_Act1_start" ones...