One thing I particularly hate - is when people post rude and snide comments about people who aren't big eaters. 'Teeny tiny' type comments really get on my nerves. If you don't consume a big mac meal and 4 donuts and a massive milkshake to yourself, followed by a half pound block of Cadburys Dairy Milk, you're a 'teeny tiny,' and guilty of competitive undereating. 🙄
I saw a thread the other week mocking people who buy a bag of chips and one large battered fish, and share it with their partner/husband. One poster said 'why are you doing this? No-one does this unless they're a pensioner.'
Then someone else said 'must be poor if you're sharing a meal meant for one.' 
It's not the done thing to mock and deride people for eating a lot, or being overweight, but it seems to be fashionable on Mumsnet to mock people who aren't big eaters. Boils my piss to be honest. Seems some people have an issue with people who don't eat a lot. There are many reasons for it, ranging from people having an eating disorder, to people not wanting to gain weight, to the fucking obvious fact that some people just aren't big eaters.
People who ARE big eaters love to project their issues onto the ones who don't eat a lot/eat small portions by mocking them, and posting snarky, sarcastic jibes about their 'suppose' competitive undereating. When people project snide comments onto people who don't eat a lot, it speaks volumes about them to be honest. 