Portion Control: A Behavioral Psychologist’s Perspective

Fresh Apple On The Branch

We know we should eat reasonably-sized portions — so why don’t we?

Matt Wallaert, a scientist and behavioral psychologist who studies why we make the food choices we do, shared some valuable tidbits recently when he was interviewed by NPR’s Renee Montagne. New York City’s plan to ban large sodas prompted the interview, but a few of Mr. Wallaert’s comments are more broadly relevant given our heightened attention to managing the volume of our food intake.

I encourage you to listen to the original interview, but if you’re short on time, these are the nuggets that magnified themselves when I first read the transcript:

  • The food scarcity that affected our ancestors influences our behaviors today. Back in the day, it was difficult to find, harvest, and prepare food, so our ancestors learned to eat as much as they could when they had the opportunity, not knowing when their next meal would present itself. Apparently, we haven’t evolved much in our approach to eating: We are genetically programmed to bring in as many calories as we can when those calories are available — whether we need them or not.
  • We exhibit a behavior called “unit bias” when it comes to eating. You don’t eat 3/4 of an apple — you eat the whole thing. As Mr. Wallaert states in the NPR interview: “The unit is an apple. So you eat an apple.” Apparently, you can apply the same logic to a bag of chips. A bag of chips is a bag of chips! Add 20% more, and it’s still a bag of chips, which we perceive — and are likely to consume — as a single unit.
  • We’re in the market for a deal, regardless of what it means to our waistline. When a fast food restaurant offers a large sandwich for $1 more than one half its size, we tend to supersize. Frugality is baked into our DNA. Pair that with “unit bias” (which makes us eat the excess food instead of packing up leftovers), and portion control loses out to the deal of the day.

My big takeaway from this short interview isn’t surprising: We should eat more consciously! We should consider each bite, relish every taste, eat only what we want, and save the rest for tomorrow’s lunch. So why don’t we? It’s up to us to figure that out.

Read more about making better food choices:

Got tips for eating consciously? Bring ’em on, and share with our readers!

Image credit: iMaffo via flickr/CC license

About The Author

2 thoughts on “Portion Control: A Behavioral Psychologist’s Perspective”

  1. Debbie Walker

    Great article, Mary, on a topic that is always on our minds, if not on our lips,
    at our house. Thanks so much!

    1. Thanks for reading! My research was very educational personally, and I’m glad you connected with the post!

Leave a Comment

Your email address will not be published. Required fields are marked *

Scroll to Top