Bottomless Soup Bowl

After discussing the effects of volume and duration (the “space-time continuum” as applied to dieting), Wansink describes what is probably his most (in)famous experiment, the Bottomless Soup Bowl.
The Bottomless Soup Bowl experiment took place in the Spice Box, the experimental restaurant dining room sponsored by the Department of Food Science and Human Nutrition at the University of Illinois at Urbana-Champaign. Wansink and his fellow researchers arranged four 18-oz soup bowls around a table. Two of the bowls were connected to food-grade tubing, which was connected in turn to six-quart vats of Campbell’s Tomato Soup. The vats were kept out of sight, and the height was adjusted so that the level of soup in the bowls was at the same height as the liquid in the vats. As the diners ate their soup, the trick bowls refilled, but not to the top. Rather, the level dropped, providing some indication that progress had been made. As Wansink tells it, there were a few kinks to be worked out, and not just in the tubing:
Of the 62 people who showed up for lunch, only two discovered what was occurring. One bent down to retrieve a dropped napkin, and quickly pointed out the Borg-like tubing under the table to the rest of his lunch companions. The second person had a much more dramatic experience. Forgetting for a moment that he was not at a medieval banquet, this man picked up the bowl to drink out of it as if he were channeling one of his Viking ancestors. It made a loud gurgle and the tomato soup-filled tube slithered up through the table like a coral snake. This made the woman next to him shriek, and the man across from him tipped over his chair in his haste to escape. These two people and their companions were dropped from the study. None of the other 54 suspected a thing.
To me, there is an interesting lesson to be drawn from the Bottomless Soup Bowl. As you know if you’ve been reading my earlier WHEE diaries, Dr. David Kessler argued in his book The End of Overeating that the American food industry is making processed food irresistible through the addition of sugar, fat, and salt. What the Bottomless Soup Bowl shows is that sugar and fat (at least) aren’t necessary to keep us eating more and more. In fact, the diners with the trick bowls at the Spice Box ate more than 50% more soup on average. Wansink says that some ate more than a quart of soup! That’s three times what the diners with the normal bowls ate.
For Wansink, the most important lesson is that we aren’t good at estimating the number of calories in our food. The “normal” diners underestimated their calories by about 20 percent – they thought they’d eaten around 123 calories, but had actually consumed over 150. The other diners thought they’d eaten 127 calories,  but they’d actually consumed 268 calories on average – their estimates were off by over 100 percent. Yet most of the bottomless bowl diners reported feeling no more full than did the others.
Wansink then refers to other studies to show that the 20% underestimate is not just an artifact of his experiment. In fact, the 20% is a typical underestimate – for normal-weight people, that is. Overweight and obese people underestimate their calorie by 30, 40, or even 50%. But these studies are not common knowledge:
Scientists, physicians, and counselors have often blamed overweight people for trying to fool others (or themselves) about how much they’re eating. Some dieticians, physicians, and family members tell them flat out that they’re “lying” or “in denial.” Hurtful accusations like these only make diet counseling effective at scaring off overweight people, rather than changing them.
Why are overweight people more inaccurate in their estimates? Wansink suggests that in fact, everyone is less accurate at estimating calories as meals get larger. In fact, says Wansink:
It seems that when estimating almost anything–such as weight, height, brightness, loudness, sweetness, and so on–we consistently underestimate things as they get larger…That Popsicle-stick skinny person eating a 2,000-calorie Thanksgiving dinner will underestimate how much he’s eaten by just as much as the heavy person eating a 2,000-calorie pizza dinner. The trouble is that the heavy person tends to eat a whole lot more large meals.
Reengineering Strategy #2: 
See All You Eat 
As I noted in my previous diary, Wansink closes each chapter with a healthy eating strategy related to the lessons of the chapter. This chapter’s strategy is a two-part strategy:
“See it before you eat it” 
Rather than eating from a Bottomless Bowl of tomato soup – or worse yet, a Bottomless Bowl of ice cream or candy – preplate your food. Decide how much you’re going to eat, take it out of the larger container, and put it in a smaller container before you eat it. Make it easy to see the level going down, like the subjects in the Spice Box who had the normal bowls, rather than the Bottomless Bowls.
“See it while you eat it” 
Or rather, keep the empties visible while you’re deciding whether to have more. If you’re eating chicken wings, keep the bones on your plate while you decide whether to have seconds. The same applies to beverages, says Wansink. If you’re serving wine at your dinner party,
…keep the empty wine bottles on the table and pour refills into fresh glasses, without clearing the others. This should help stretch your supply of North Dakota wine.