Brian Wansink in his book Mindless Eating describes the ways in which portion sizing has changed over the years, and how this affects our behavior. There are two basic ideas here:
Most of us will eat all that we are served — no matter how big the portion is. If we are served a small bag of popcorn, we’ll
eat that. If we are served a bucket of popcorn, we’ll eat that. (Sounds familiar)
If we consistently eat bigger portions, bigger portions will seem “normal”. We’ve lost our perspective on how much we should really be eating.
We often eat more when we’re multitasking. Ever started snacking while watching TV or playing video games, then found yourself staring at an empty bag or bowl, wondering where it all went? Your attention was elsewhere, so your eating machine just went on autopilot.