A new study has suggested that chewing each mouthful of food for longer might help you lose weight, and also reduce the amount of calories consumed during a meal. The study showed that volunteers who chewed each mouthful 40 times ate 12 per cent less food than those who chewed just 15 times. It is thought that chewing for a long time checks over-eating as the brain is given more time to receive signals from the stomach that it is full. It also apparently lowers the levels of ghrelin, a hormone that controls hunger by circulating in the digestive system. Researchers at Harbin Medical University in China carried out a couple of experiments on 16 slim men and 14 obese men in their late teens or twenties. In the first experiment, they tested whether the obese men chewed their food differently to their lean competitors or not. Each volunteer was treated to a pork pie and captured by a secret camera to notice the number of times they chewed before swallowing. The results showed that even though the obese men chewed at the same speed as the slim ones, they swallowed their food in quicker time than the leans. In the second experimnt, another portion of pork pie was given to both groups to chew 15 times before swallowing, and then the exercise was repeated but they were asked to chew 40 times instead. The study found that when volunteers chewed for longer they consumed 11.9 per cent fewer calories, no matter if they were lean or obese. "Research indicates eating quickly, gorging and binge eating have a substantial effect on being overweight," the Daily Mail quoted the researchers as saying. "Our results showed obese participants chewed less and ingested more quickly than lean ones," they added. Blood tests that were meted out 90 minutes after eating also found that the levels of ghrelin was reduced when the volunteers had chewed the food 40 times rather than 15. The findings were published in the American Journal of Clinical Nutrition.