This dream is a warning to take care of our health.
Dream dictionary: Slimming dream meanings
Seeing weve lost weight in dream is a warning that we must take care of our health, as diseases are around us. If we dream we are very thin, it means that the risk of disease is very close, and the thinner we see us, the more important it will be.
If in the dream, the dreamers abdomen is fat, then it usually means hopes of wealth, honors or professional success. On the contrary, if in a dream, the dreamers abdomen is slimming down, then such dream almost always is a symbol of poverty.