doctor right??

Hi, so ive been diagnosed with pcos for a few years now.. ive lost quite a bit of weight but recently ive put on a little bit.. i have a appointment today and saw a different doctor and he said to me that i should aim at eating less than 1000 calories aday... ive been told you need atleast 1200... the app which i use said that its not recommended and he also suggested getting meal replacement milkshakes... with metformin... that doesn't sound like he knows what metformins like...