Men who attend slimming classes lose twice as much weight when they exercise in an all-male environment, a new study has found. Researchers at Leeds Metropolitan University have found that men who joined classes which included no women lost almost a stone on average, taking into account those who missed some of the 12 weekly meetings. In contrast, those who attended slimming club meetings dominated by women lost just over half a stone. Furthermore, study participants who completed the all-male course lost nearly one and a half stone on average and saw their waistlines reduced by approximately two inches. Lead researcher professor Steven Robertson claimed that the results could be attributed to the fact men feel more comfortable around fellow males and enjoy being part of a team. Zoe Hellman, head of public health at Weight Watchers, which funded the research, added: \"A lot of the men did say that they felt a very female-dominated meeting might put them off contributing or talking about things that were important to them.\"