Scientists have worked out why many smokers put on weight when they quit, paving the way for drugs that counter the problem.A pill could help smokers who have given up from turning to food instead, as well being a benefit to non-smokers who are losing the battle of the bulge.Researcher Marina Picciotto said: ‘Many people say they won’t quit because they’ll gain weight.‘We would like to help people maintain their weight when they kick the habit, and perhaps help non-smokers who are struggling with obesity.’In experiments on mice, Professor Picciotto homed in on the tiny proteins on the surface of brain cells that nicotine latches onto. Scientists at Yale University in the U.S. found that when nicotine hits one type of protein in the brain it triggers a craving for cigarettes while a second protein sets off a reaction that dampens the appetite.They also discovered that a drug can trigger the second protein, the journal Nature reports.The fact that nicotine cravings are tied into a different protein is important, because it means that any diet drug would not also make people start craving tobacco. Researcher Dr Mariella De Biasi said: ‘Identifying this receptor is important for the understanding of the mechanisms related to addiction, weight and smoking.‘Right now, these results are only in mice, but this could open the door to therapeutic measures to help people quit smoking without gaining weight.‘For many people weight gain is a deterrent to quitting smoking, and our results suggest that drugs that stimulated the alpha-3 beta-4 nicotinic receptor might help to limit weight gain following smoking cessation.A new diet drug would also be hugely popular with non-smokers who are struggling with their weight.With Britain battling the worst weight problem in Europe and just one obesity drug on the market, there is an urgent need for new ways of turning the rising tide of obesity.However, with two diet 'wonder drugs' that tinkered with brain chemistry banned over safety fears in recent years, any new drug have to pass stringent safety tests before being cleared for sale.With any drug based on the new research still several years from the market, the scientists say that their findings shouldn’t be used as an excuse for people to smoke.The damage done to the heart, lungs, fertility and even to the face far outweigh any benefits of losing a few pounds, they warn.Source: Daily Mail.com