American Serving Size

Today I had dinner with my lab at Dinosaur BBQ. I've never been to Dinosaur BBQ, and did not bother to search on Yelp pictures beforehand to see how much portions their servings actually were. There were five of us to share a family barbecue style, which said were for 3 adults. Naturally, this got us into debating between getting two servings or one. I guess we tried to used statistics--of five of us, three were women, who claimed eat less than average adult. Two other guys were tall men, who claimed to eat as much as other people. This is about 0.7*3 + 1*2 = 4.1 "average" adult, so we ordered one family barbecue style and a plate of appetizers.

To our surprise, we ended up with SO MUCH FOOD. Although I tried to fit in as many food in my stomach for dinner, we had lot of leftovers that we took back home. I'm not complaining about the generous portions of this restaurant, but I couldn't help but question how accurate the restaurants are about portion sizes. Do they actually take statistics, or accumulated worldly wisdom to decide portion size? Is there a good way of defining this? And how come five Columbia students fail to order an appropriate amount of food? This always seems to be a challenging problem whenever I'm eating out in a group.