If there is no apparent leaks, then you ave another possibility.ne is you burning it, which means your piston oil rings are gone, or you have "internal" leak. Possibility from the block to antifreeze, check there, but Toyota engine normaly do not burn oil. I have 107K and it holds from oil change to oil change (5K mi) with no losses. Also emission test will tell you if your engine burns oil.
I hope it helps.