My Uncle Charlie hits the fridge right after dinner. He isn’t hungry. So why does he eat?
Why people eat when they are not hungry is the topic food psychologist Brian Wansink takes on in “Mindless Eating,” drawing on his own studies and other research.
One reason we eat too much, he argues, is that we typically use “I have eaten all that is on my plate” as a cue to stop eating rather than the far better cue — “Am I still hungry?”
In one experiment, Wansink showed college students an 18-ounce bowl of tomato soup and asked them, “If you were going to have this soup for lunch, when would you decide to stop eating?”
More than 80 percent of these students used an outside visual cue — “I’ll stop eating when the bowl is empty” or “I’ll stop eating when the bowl is half empty.”
Only about 20 percent used an internal appetite cue — “I’ll stop eating when I am full.”
What would the first group of students do if they were eating from a bottomless bowl? Would they continue eating even though they should feel stuffed?
Wansink rigged up a clever experiment to find out. He invited more than 60 students to come for a “free lunch” — tomato soup. They were unaware that this was an eating experiment.
Wansink gave them each a soup bowl fastened to a table. Half the students ate from normal soup bowls. The other half ate from “bottomless bowls.” Invisible pipes hooked up to the bowls kept the soup flowing, no matter how much the students ate.
The invisible pipes did not fill the soup bowl to the top, just part-way. This way, the students would not catch on to the fact that their bowl was never empty.
“People eating out of the bottomless soup bowls ate and ate and ate,” Wansink reports. “Many were still eating when we stopped them, 20 minutes after they began.
“The typical bottomless bowl student ate around 15 ounces, but other bottomless bowl students ate more than a quart. (The students without the bottomless bowls ate 9 ounces, a little less than an undiluted can of tomato soup.)
“With a couple of exceptions, such as Mr. Quart Man,” Wansink reports, “the students didn’t comment about feeling full.”
In another experiment, he asked distinguished food specialists from the Nutritional Science Division to come to an ice cream social.
When his guests came, they were given either medium size 17-ounce ice cream bowls or huge 34-ounce ice cream bowls. The people went through a line and scooped their own ice cream into their bowls.
Those given the huge bowls served themselves huge amounts. They dished out almost a third more ice cream to themselves as did those with the smaller bowls. And these were nutrition specialists who, of all people, should have known better.
Most people regulate their food intake by asking: “Does my portion fill my dinner plate?”
But the size of our modern dinner plates has grown along with our waistlines.
Talking to antique dealers, Wansink learned that many of their customers picked up an antique dinner plate and thought it was a salad plate. They were used to eating from large-size modern dinner plates.
Just for fun, I took out my grandmother’s antique china and compared the size of her dinner plates to the size of my Crate and Barrel dinner plates. The eating space between the decorative rim on my grandmother’s dinner plate measured a measly 7 inches. The eating space on my modern dinner plate measured 10 inches.
I have a trick to control my own desire to overeat. I serve my dinner on a salad plate.
But my salad plates measure 8 inches. My salad plates turn out to be a full inch bigger than my grandmother’s dinner plates!
What we need to do to control our weight, advises Wansink, is not to go on a special “diet” but to change our visual cues signaling how much we should eat.
Maybe we naturally eat like wolves, as much as we can find (on our plates), to protect ourselves against a famine that never comes.
Judith Kleinfeld, a longtime columnist for the Daily News-Miner, holds a doctorate from Harvard and is a psychology professor emeritus at the University of Alaska Fairbanks.