To give them a frame of reference, you could say "I'm 63 kg, so I would take 1.26 grams" (or whatever the numbers are).
I suggest you complain to the professor's boss about her. Anyone who does not know his body mass in kilograms (if he knows it at all) or the number of milligrams in a kilogram is seriously behind the times. I was 36 kg sometime in the 70s and I have never known my weight in any other unit. phma
