If you are of a certain age, perhaps your parents told you to eat slowly. They may have said something about better digestion but if you were one of many poor people it also had to do with feeling fuller on less food. 

Common wisdom was your brain did not keep up with your stomach so if you slowed down, your brain had time to realize the stomach was full. In general experience, that seems to hold up. You rarely see obese people who eat really slow.(1) Two new studies by researchers at the University of Rhode Island bear this out and found that men eat significantly faster than women, heavier people eat faster than slimmer people and refined grains are consumed faster than whole grains, among other findings.

One study used self-reported eating rates, they say those reflect an individual's actual eating rate, and found that fast eaters consumed about 3.1 ounces of food per minute, medium-speed eaters consumed 2.5 ounces per minute, and slow eaters consumed 2 ounces per minute.

The researchers also found what Kathleen Melanson, URI associate professor of nutrition, talking at the annual meeting of The Obesity Society in Orlando, described as "very strong gender differences" in eating rates. At lunch, the men consumed about 80 calories per minute while the women consumed 52 calories per minute.

"The men who reported eating slowly ate at about the same rate as the women who reported eating quickly," said Melanson. The second study examined the characteristics associated with eating rates and found a close association between eating rate and body mass index (BMI), with those individuals with a high BMI typically eating considerably faster than those with a low BMI.

"One theory we are pursuing is that fast eating may be related to greater energy needs, since men and heavier people have higher energy needs," said Melanson.

In what Melanson called her favorite result, the study also found that the test subjects consumed a meal of whole grains – whole grain cereal and whole wheat toast – significantly slower than when eating a similar meal of refined grains. "Whole grains are more fibrous, so you have to chew them more, which takes more time."  

While the link between eating rate and obesity is still being studied, Melanson said that her research has demonstrated that eating slowly results in significantly fewer average calories being consumed."It takes time for your body to process fullness signals," she concluded, "so slower eating may allow time for fullness to register in the brain before you've eaten too much."

 In 2007, Melanson conducted a study confirming the common wisdom that eating slowly reduces food intake. That study found that women who were told to eat quickly consumed 646 calories in nine minutes, but the same women consumed just 579 calories in 29 minutes when encouraged to pause between bites and chew each mouthful 15 to 20 times before swallowing.

NOTE:

(1) Queue exceptions in comments which will claim they invalidate the entire study.