Scientists believe they may have found a potential new way to treat obesity by stopping the stomach from expanding.They have identified two cell proteins that relax the gut and help accommodate a big meal.In theory, a drug which blocked this relaxation would reduce a person's ability and desire to gorge on excessive amounts of food.The University College London study appears in the Journal of Pharmacology and Experimental Therapeutics.The two proteins identified by the researchers - P2Y1 and P2Y11 - control both fast and slow relaxations of the gut.The human stomach has a "resting" internal volume of 75 millilitres, but by relaxing its muscular wall can expand to an internal volume of two litres of more.This expansion is controlled by nerves inside the stomach wall which release molecules that stimulate P2Y1 and P2Y11, which are embedded in muscle cells, also in the gut wall.Researcher Dr Brian King said: "The mechanism of slow relaxation of the stomach might represent a future drug target in the fight to control weight gain and reverse obesity."We are looking to identify drugs that would block the P2Y11 receptor and, therefore, prevent slow relaxation of the stomach."As a result of blocking the P2Y11-based mechanism, meal size would be smaller, offering the person a better chance of regulating their food intake."Dr King said this would represent a new approach to weight control. At present, gastric banding or stomach stapling are used to reduce the maximum volume of the stomach.But these are tricky surgical procedures, and carry a risk of serious side effects.Dr Ian Campbell, medical director of the charity Weight Concern, agreed that an alternative treatment for obesity would be useful.He said major surgery such as gastric banding was expensive and risky, and although current drugs that focused on appetite suppression, or on reducing fat absorption by the body did work, their long term effects remained unclear."We still have much to learn about the complex way we control our appetite, and food intake," he said."For many the use of medication can be an important help towards their weight loss goals, but lifestyle change remains the best way of controlling weight."Source: BBC