This book has a great subtitle: Why We Eat More than We Think.
I saw Wilson's mention of Mindless Eating and gave it a read. Good stuff! Brian Wansink is a professor at Cornell and he's spent a career doing psychological experiments on people in restaurants, bars, and fake movie theaters to see how people decide what, and especially how much, to eat. For example, he gave stale popcorn (perfectly clean, just stale) to people at a matinee. People complained about the popcorn's taste. But they still ate it. And the people who got bigger containers ate more than the ones who got smaller containers. So: people will eat mindlessly at a movie, and the more you give them, the more they're going to eat.
The book is full of hilarious experimental designs. In one, they created a never ending bowl of soup.
Some fun facts: Wansink suggests portioning out your food in the kitchen and keeping to those amounts (you can serve the vegetables on the table "family style"). Make good foods easy to eat and bad foods harder to eat (put the chips in the back of the cupboard, leave fresh fruit out on the table). Use smaller containers (if you buy at Costco, put the food in smaller Tupperware in the kitchen, and keep the massive amounts out of sight) and smaller serving utensils (taller cups look bigger than wider cups; dinner plates are now 12" diameter whereas a generation ago they were 8" [for the record, ours are 10"]). The person who shops and cooks controls 72% of the family's nutrition.
He also points out that we don't notice 100 calories a day either way, so if you just cut out that 100 calories, you'll lose weight. Another fun fact: 3500 calories is about a lb. of body weight.
Oh, the answer to the obvious question is Yes, food companies use his research in designing restaurants and menus, but No, he does not take corporate money for his research which is published in respected journals like JAMA and others.
There's a website that goes with the book here.