Want to lose weight? It's all in the chewing

Researchers from the Harbin Medical University found that thoroughly chewing each mouthful of food reduces the overall amount of kilojoules consumed in that meal and also appears to lower levels of the "hunger hormone" ghrelin in the digestive system.

In the study of 16 slim and 14 obese young men, those who chewed each mouthful 40 times were found to eat12 percent less food than those who chewed just 15 times, the UK's Daily Mail reported.

First to determine whether obese men ate quicker than the lean men, the volunteers were given a pork pie and filmed by a secret camera to test how many times they chewed before swallowing.

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Researchers found that while the obese men chewed at the same rate as the slim men, they swallowed their food much more quickly.

In a second experiment, both groups of men were given a pork pie to chew 15 times and then swallow before and then were asked to repeat the experiment, this time being asked to chew their food 40 times.

In the second experiment, both groups of men took in nearly 12 percent less kilojoules then when they ate their food slower and blood tests taken 90 minutes later showed volunteers also had much lower levels of ghrelin when they had chewed each portion 40 times.

"Research indicates eating quickly, gorging and binge eating have a substantial effect on being overweight, said the researchers.

"Our results showed obese participants chewed less and ingested more quickly than lean ones."

The study was published in the American Journal of Clinical Nutrition.