to think that no one has any idea of reasonable portion sizes?

[Mallorie]

The amount of food I see people eating at work is just mind-blowing. I batch cook most Sundays - nothing special or particularly healthy, just stuff like veggie pasta bake or sweet potato chili with rice, and I see people in the office microwaving similar food at lunch - but they're eating the amount I make for 5 meals over the week in one go! The guy sitting next to me will bring in 4 entire ham sandwiches and eat them at noon - AFTER having a sausage butty at 10am.
No one I've noticed ploughing through this food is obese, no more than I am, so maybe they don't eat much at home? If I ate those portions I'd be sick but if I got used to it I'd be the size of a house in no time.
Interestingly, I rarely see the people at work who ARE obese eating much of anything, which is odd.

I know quite a few of those 'greatest achievement is being slim' types and they are such judgemental bores!

I put them in the same category as those adult weirdos who are still bizarrely proud of their A-level results (those ones come out every year at results time to be all 'but in my day they were much harder, my BBC is then equivalent of AAAAAA now!') - they're very strange, and I just think, 'is that really all you've ever done?'

I just knew some bellend would come on and tell the OP to 'get a hobby'.

YANBU. When I go to a restaurant I can't believe the portion sizes they serve for one person. If I'm with my mum we just order one thing between us and even then we often end up leaving some. I have some old vintage dinner plates and they're much smaller than contemporary ones. We definitely eat more than we used to.

When I was big I would never eat infront of anyone. My eating was done alone behind closed doors!
And I agree that most people know what a portion size is, they just ignore it.

I think it's odd that the likes of Jamie Oliver bang on about obesity but he has NEVER mentioned restaurant portion size (probably because doing so could directly affect his own business.) Meals in restaurants tend to be way bigger than what I think most people (OP's colleagues aside) would plate up for themselves. And in the UK we don't have much of a culture of asking for dog bags although I tend to ask for one.