Informal Science Makes a Difference


A couple of years back, the Today show collaborated on an experiment with Brian Wansink, a Cornell University professor who had previously been executive director of the Center for Nutrition Policy and Promotion, a division of the U.S. Department of Agriculture. To prove his point that the sensation of fullness can be engineered, they offered a TV audience a free buffet.

The subjects of the experiment were divided into two groups of 12 each. Jeff Rossen and Josh Davis wrote:

For the first group, the buffet was laid out with fruit and salad first, then fatty pasta dishes at the end. The first group was given normal size plates and normal serving spoons.

[For the second group…] The order of the food was switched so that the healthy stuff went in back while the fatty stuff was placed at the beginning. In addition, group two was given slightly bigger plates and serving spoons. But the food itself was exactly the same.

The first group loaded up with the items they saw first, the healthful offerings, and left little space on their plates for high-calorie pasta. The second group, encountering the pasta first, took more of that.

Prof. Wansink summarized:

The first food you see in a buffet is a trigger food… What we find is, about 70 percent of what people are taking are the first three foods they see.

The second group of subjects, with the larger plates and spoons, averaged around 1,500 calories worth of pasta per person, while the smaller-plate group kept their pasta consumption down to around 890 calories. Also, the large-plate group ate about one and a half times as much total food as their small-plate counterparts. Apparently, humans are subconsciously imprinted with the conviction that a plate must be full.

The message is to use smaller plates and serve healthier foods first. By the time Today did their televised experiment, some American schools were already trying new methods of presenting and serving in their cafeterias.

By applying to school lunches the science of behavioral economics as advocated by Prof. Wansink, administrators were able to increase the consumption of salads. All they had to do was rearrange the physical environment so the salad bar was encountered first.

Fruit consumption was increased by placing it, rather than chips and desserts, in the checkout line. The researchers learned that keeping the lid of the ice cream freezer shut would cut ice-cream sales in half. Students still had a choice about what to eat, but making the high-calorie, low-nutrition items less visible and less convenient makes a noticeable difference in eating habits at school.

The take-home message

The obvious lesson for parents is to do the same at home. If the kitchen must contain snack items, put them away inside cabinets so the temptation doesn’t jump up, multiple times per day, and hit people in the face. At mealtime, serve the healthier items first, and, as for the rest, don’t leave serving dishes on the table.

Make it just a tiny bit inconvenient to take a second helping of high-calorie dishes. Use smaller dinner plates and spoons. Stash ice cream it the back of the freezer, behind and underneath other things, to make it just a bit harder to access. All these little “tricks” can add up, making the path to obesity avoidance a little smoother.

Your responses and feedback are welcome!

Source: “Experts say you can trick your mind into helping you lose weight,”, 04/22/14
Photo credit: Natalie Maynor via Visualhunt/CC BY

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About Dr. Robert A. Pretlow

Dr. Robert A. Pretlow is a pediatrician and childhood obesity specialist. He has been researching and spreading awareness on the childhood obesity epidemic in the US for more than a decade.
You can contact Dr. Pretlow at:


Dr. Pretlow’s invited presentation at the American Society of Animal Science 2020 Conference
What’s Causing Obesity in Companion Animals and What Can We Do About It

Dr. Pretlow’s invited presentation at the World Obesity Federation 2019 Conference:
Food/Eating Addiction and the Displacement Mechanism

Dr. Pretlow’s Multi-Center Clinical Trial Kick-off Speech 2018:
Obesity: Tackling the Root Cause

Dr. Pretlow’s 2017 Workshop on
Treatment of Obesity Using the Addiction Model

Dr. Pretlow’s invited presentation for
TEC and UNC 2016

Dr. Pretlow’s invited presentation at the 2015 Obesity Summit in London, UK.

Dr. Pretlow’s invited keynote at the 2014 European Childhood Obesity Group Congress in Salzburg, Austria.

Dr. Pretlow’s presentation at the 2013 European Congress on Obesity in Liverpool, UK.

Dr. Pretlow’s presentation at the 2011 International Conference on Childhood Obesity in Lisbon, Portugal.

Dr. Pretlow’s presentation at the 2010 Uniting Against Childhood Obesity Conference in Houston, TX.

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