This happened years ago, when I was about 16 or 17, at a BBQ. The hosts were our family friends, who also invited some of their relatives.
Well, me and my little brother are both vegetarians, but everyone else who was there was a meat-lover (the kind of person who will not consider any meal without meat "a real meal"), so there wasn't much food to choose from for us. We mostly just ate the salads, veggies, bread, rice, etc. Not a big deal.
Unfortunately, the hosts invited a family of planets - some of the most obese people (and children) I've ever seen. Both of the parents were wider than my mother and father together, and the daughters were on the same path. I couldn't tell how old the girls were, but they were definitely younger than me, while being 2-3 times as wide, but still shorter than me.
While the planetoid family was stuffing their faces with fatty dark meats, chicken wings and potatoes, the motherham looked at my mum and said "I'd never allow my kids to become vegetarians. It's just so unhealthy". She then looked at my veggies with disapproval, and went back to consuming her weekly recommended amount of meat and calories in one sitting. We were (sadly) too shocked to say anything, so we just ignored her remarks.
Tl;dr: Morbidly obese failure of a mother with morbidly obese children thinks she knows what a healthy diet for a child is, decides to criticize mother of 3 healthy children to maker herself feel better.