@thecatfromjapan
A certain type of man does this for attention. Which is very weird. In theory, it's 'negging' - they prey on female insecurity to get into a relationship. That's creepy enough - but I think some men don't even have a plan, they just follow some sort of hard-wired algorithm.
Agree with this, but don't think it's being done to get into a relationship. It's being done to keep women in their place.
@nutellafitzgerald
I reckon that comment wasn't anything at all to do with you and everything to do with him. You could have been anybody.
What he wanted was to feel dominant and in control because he knows he is neither.
I've seen this kind of behaviour so many time and it's always the self-loathing types that do it.
Agree 100%
@donajimena
fireball I've been called the same as OP too and I'm a size 10. Its just an utter dickwad default phrase designed to try and hurt/dominate and 'impress' their equally dickish mates.
Agree with all of the above. And yeah it is 'negging...' Basically trying to make a woman feel worthless, and like shit, to make himself feel better about his worthless, 'piece-of-shit' self, and to look 'big' in front of his mates. I guarantee at least one or two of his mates would have felt bad for you, but too embarrassed to say anything.
Look at at Stifler from American Pie and Jay from The Inbetweeners; gobby, rude, and obnoxious, and insulting to women, and most of their mates cringe when they speak.. None of the rest of this group in real life, ever have the nerve to challenge the vile cunt in the group though, in case they look 'weak.' (coz talking down to women and putting them in their place is a strength. 
)
Like many women here, I have been insulted by men when I have been out, and called fat, a slag, a whore, a cunt, and a hideous oxen (that was my fave moment, as the man spat at me as this car was driving by and screamed 'die you fat monster' at me as the car spend past.) I was 12 stone and a size 16 and 5 ft 4, so was 'curvy' but not huge.
I am shocked by the amount of posters here saying similar things have happened, it's actually dreadful. In some ways comforting though, to know it's not just happening to you. Still not great obviously!!!
Although it is tempting, I don't subscribe to the 'scream back at him,' 'punch him,' 'hit him in the face with a kebab and he will jolly well be taught a lesson' type of comments. These dreadful creatures already hate women and are full of self loathing. Attacking them back rarely ends well, in a situation where they are with a group of other men.
A pal of mine (around 25 years ago,) fought back, when a man said 'oy slag, suck me cock!' and slapped her arse in front of his 5 or 6 mates in a pub, and she bit back and said 'fuck off!' and shoved him back slightly, then turned her back on him.
Before she knew it, he had his hand round the back of her neck, and shoved her face into the wall, fracturing the bridge of her nose and breaking 2 front teeth, then he jerked her head back and threw her on the floor, and said 'mess with me yer fucking cunt and I'll fucking kill yer.'
3 or 4 of his mates jeered and threw their arms up in the air with glee at their mate putting this 'cunt' in her place. A couple of them looked uncomfortable and said 'fucking 'ell man' steady on..' and within 30 seconds they had all disappeared. We never saw them again, and there was no cctv where we were. We called the police but they never found them.
So, don't confront them, and try and come out with a smart put-down, or think you will be 'putting him in his place' .. this is already a man who hates women, and he is not going to think you are funny or clever, and you could find yourself in danger.
Just walk by and ignore him. People like this crave attention, and if they are ignored it will disappoint them. Hopefully they pick on the wrong person one day and they get their face smashed in.
(((HUGS))) to you @itsallgravybaby 
Please don't let this get you down. You are not fat, you're gorgeous, and as has been said, this man just need an insult to throw.
Like a few women here, I have also been insulted when I was a size 10 and 9 stone. One example is ... I was walking down the street to the beach once, with my shorts and vest top and flip-flops on, (in 90 degrees F weather,) and had some random man pull up and wind down the window, and say 'OY, you fucking fat dirty slag, who the fuck do you think you are, you filthy cunt, dressed like a fucking slag, dirty fucking slag slag slag!!' with a menacing evil sneer on his face. I was literally TERRIFIED and darted into a shop.
I know many other women who have had similar things happen to them, ranging from catcalls and insults, to blatant threats.... Including young relatives of mine, and it's so upsetting to know they have had to go through this. I really don't know why these men feel the need to be so evil, and wonder what their mothers (and other female relatives) would think of them.
Have to agree with the poster who said it never happens after you get to middle age. There are some tough things about ageing, but not getting constantly hit on or verbally attacked by random males is one of the benefits.
@Deltonia (end of previous page,) all those things that happened to you and your parents are awful. I am so sorry.
I am also sorry for all the people on here who have suffered abuse at the hands of tiny little men with low self worth...
(((HUGS))) for you all.... 
One last thing, this post by @pictish speaks volumes,.......
Successful, intelligent, happy, well adjusted, confident and fulfilled people do not shout abuse at random people passing by. They just don’t. The bitterness, stupidity and cruelty it takes to perform like that comes from an inner well of dissatisfaction and self-loathing...and on that you may be certain. It must suck to be them.