rez said:
I was weighing myself on the tantia scale and he walked passed and saw that my bf% came in at 15%. He started hasselling me saying that it was too low blah blah blah...
I dont really care about what he says, but he did say that if it goes lower I could suffer from low bone density and oesteoperosis...is this true?
"Too low" depends on the individual, and what they're doing to get to or stay at a certain level of bodyfat. There is no magic bodyfat threshold that fits all women, and it certainly can't be based solely on a Tanita scale reading.
If your bodyfat is dropping because you're training hard, eating well, you feel great, your performance is steadily improving, and your bodily functions (e.g. menstrual period) are working, then Great! - pay him no mind.
But if you're killing yourself for the sake of low bodyfat: overtraining, crash dieting, experimenting with suspect supplements, you feel like shit, your strength is dropping, etc., and this same guy has been watching this happen, then he should say something.
It's one thing to diet down for competition, because it's just temporary. It's something else to force your body to be something it's not, or before it's ready. Bodies all have a way of paying us back when we take things too far or too fast. Only you know what your situation is, so only you can interpret what he meant.