He's having a go at you, and he's basically called you fat, and you have doubts about his honesty and YOU HAVEN'T EVEN STARTED DATING YET?
Lass, the hills are over there ===>
^This.
Look, you've said you're fragile, so block him. You're not even boyfriend/girlfriend, yet he's already angry at you. He's a liar, and the reason he's getting angry, is that you called him out on his lie. He wanted you to meekly accept what he told you. He wants a woman he can bully around and abuse. If you have low self esteem because of your weight, he will tell you that you're lucky to have him, as no-one else will want you, and you will start to believe him, and won't leave him.
This man is clearly showing you what he's like, and you'd be a fool to continue talking to him, let alone start dating him.
Do the Freedom Programme before you start dating anyone, and work on your self esteem. If you've had a string of dickhead boyfriends, you obviously don't recognise the red flags.
Block him now, and don't have any more to do with him.