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There's little solid evidence showing that eating more slowly affects how much you weigh.
By Barbara Rolls, Ph.D.
msnbc.com contributor
updated 1/11/2008 8:27:12 AM ET 2008-01-11T13:27:12

It's long been thought that if you wolf down your food, you'll consume more calories during meals. People trying to control their weight are told to pause between spoonfuls and to put the fork down while chewing.

Diet experts have been pushing this advice since the early 1970s, but does it really work? It started with the suggestion that obese people eat faster than lean people. In fact, there's little solid evidence showing that eating more slowly affects how much you weigh.

The handful of tests that have tried changing people's eating behavior have shown mixed results. In one study, the amount of food per bite was reduced and this slowed the rate of eating. But the participants ate for longer and ended up consuming the same amount of food. In a separate British study, people who paused between bites actually ate more.

The perception is if you slow the pace of your eating, your body has time to release hormones signaling that you've had enough and you'll consume fewer calories in a meal. While many say  it can take about 15 minutes for your body to register satiety, some research indicates that it can take up to an hour or more for the biological signals for fullness to peak.

Guys eat faster
Only one study, conducted in 1991 at the University of Pennsylvania, has tested whether a slower eating rate helped participants in a behavorial program lose weight. At first the approach was promising — eating more slowly was associated with greater weight loss. But the slower rate was not sustained. After 10 months in the program, there were no longer differences in weight loss.

A team of investigators from the Pennington Biomedical Research Center in Baton Rouge, La., have just published a new study in which eating rate was paced by a beeping computer. Cutting the usual rate of eating by half had no influence on how much women consumed during a meal of fried popcorn chicken, but the men ate about 10 percent less (100 calories) when they ate more slowly.

It is not clear why there was a sex difference, but because men tend to eat faster than women, slowing down may have a bigger effect on them. Another possibility, according to Corby Martin, clinical psychologist and one of the authors of the study is: “Women tend to be more cognizant of how much they eat, so they may stop before they’re entirely full."

Food cues
In our food-laden environment there are plenty of reasons we keep eating after we have met our calorie needs. What matters is the palatability or variety of the food, not specifically the rate at which it was consumed.

Feeling satiated is more than filling your stomach and changes in hormones. As you eat, the pleasure you get from the food slowly declines. If you’re hungry, the first bite of a food you like is intensely delicious. Slowly, as you finish your meal, you find the food less pleasant. But a new course will reawaken your appetite.

We call this sensory-specific satiety: you become full for one specific sensory experience — say, the taste of pasta — but not others. That is why after lots of salty foods you still enjoy foods with a different taste, such as a sweet dessert. Serving meals with lots of different sensory experiences prolongs eating and probably has a greater influence on how much you eat than how fast.

The form of the food you're eating may also be important. In a new study from my lab at Penn State, we found that people who ate an apple a few minutes before lunch consumed about 190 fewer calories than when they consumed apple juice. It could be that the increased amount of chewing required to eat the apple triggers responses that cause us to feel fuller and consume less.

Savor the flavor
You don’t have to consciously pause between bites, but eat at a pace that maximizes your enjoyment of the food. If savoring the flavors and textures makes dining a more pleasurable experience, then go for it.

In the end, it’s more important that you choose foods that are low in calorie density , meaning they give you fewer calories per bite. That way no matter what your eating rate, you won’t take in too many calories.

Barbara Rolls is the author of “The Volumetrics Eating Plan,” which offers tips on how to eat more fruits and veggies and lower the calorie density of recipes.

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