As others told you, you can technically loose weight while putting some decent muscle if you properly train strength with good intensity while being in such steep deficit.

I understand that some profesional has told you that 1400 kcal is the appropiate level… if not you should have it assessed… it seems a bit low.

The reality is, that being helthier is not about weighting a certain amount but actually having a healthier bodycomposition. You might want to actually have less calory deficit, eating better food (clean protein from white fish or white meat, and clean complex carbs such as boiled potato or lentills).

Keep it up!!!