I wouldl like to lose 1 1/2 stone and have joined a gym. I naively thought I could exercise, say, 4 times a week and then the weight would fall off. However, it seems it's not that simple. Of course I realise that I have to be careful with my diet but I've read that it's 80% diet and 20% exercise - so am I wasting my time and money exercising so much??