I agree with Jerz. Lying to adcom is a bad idea. Remember, you have to interview at many of these schools as well, and it's much easier to argue your case if you're actually passionate about what you want to do. If you're in non-profit and want to go to IB, that's fine - just make a strong argument for why you're uniquely qualified to make that switch and why you'll be successful at it.
I think being as specific as you can in writing about your goals will also help. Instead of just saying you want to do consulting, say "I want to do consulting in x industry at companies like ABC, because of my background/interest/passion in Y." That indicates your interest, your level of research into your desired field, as well as your own understanding of how you, with your background, can break into that field.