Wash the pear and the carrots, and then peel them together with the pineapple. Pour onto it the grapefruit juice, in a blender. Add the oils and the vinegar, and finally the ice cubes. You can control the density of the smoothie with the quantity of the grapefruit juice. Blend the ingredients well so as to get a nice, silky consistency.
Enjoy your smoothie right after mixing it.