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Eating slowly may lower the energy intake during a meal, enhance the enjoyment of food and suppress hunger later, a new medical study has shown, validating what some medical experts say is traditional wisdom.

The study by researchers at the Texas Christian University in the US has shown that eating speed influences food intake, water consumption and satiety during meals, with certain differences between normal weight and overweight or obese persons.

“Slowing the speed of eating may reduce the amount of food consumed as well as lead to a greater degree of fullness or less hunger later on,” said Meena Shah, professor of kinesiology at the university who led the study. “I would not recommend timing a meal though — eating should be an enjoyable experience without having to check the time,” she said in a podcast released by a research journal where her study is published.

While three previous studies have examined the effects of eating speeds on persons with different weights, the results have been mixed. One study indicated lowered energy intake, while two others found no effect.

In the new study, Shah and her colleagues compared how eating fast or slow influenced the energy intake of 35 persons with normal weight and 35 overweight or obese persons. Their findings were published today in the Journal of the Academy of Nutrition and Dietetics.

Both sets of volunteers were asked to eat vegetarian pasta on two different days —once fast, taking large bites, chewing quickly and not pausing between bites, then slowly, taking small bites, chewing thoroughly and pausing between bites.

The researchers found that eating slowly significantly reduced the meal energy intake of normal weight people, but not as much in those who were overweight or obese, although both sets of people consumed slightly lower food when eating slowly.

A slow meal lasted about 21 minutes, while a fast meal lasted about nine minutes.

The study showed that both normal and overweight or obese volunteers consumed significantly more water during the slow meals than during fast meals. “Water adds weight to a meal,” Shah said. “The higher water intake during slow eating also reduced the energy density of the meal which reduces energy intake,” she said.

When volunteers with normal weight ate slowly, they also consumed less food. But both groups of volunteers reported less hunger, while those with normal weights also reported greater fullness an hour after the meal.

“This study shows that ancient wisdom is correct,” said Anoop Misra, an endocrinologist and chairman of the Fortis Centre for Diabetes, Obesity and Cholesterol, New Delhi, who was not associated with the study.

“The more you masticate food, the better it is in terms of weight,” Misra said. “But this is a short-term study. It would be interesting to observe over a longer period of time whether slow eating can influence factors such as blood sugar, lipids, and blood pressure in both normal weight and obese people.”

Shah said smaller bites, gaps between bites and frequent sips of water during a meal will naturally slow the speed of eating. The study participants took about 21 minutes for the slow meal. “Dinner with friends or family in a relaxed atmosphere could easily take that time, if not more,” Shah said.

Shah and her colleagues are now trying to understand how the speed of eating may affect hormones that influence hunger and fullness.