Sial, it could be your age. I know that most women put weight on, without doing anything different, once their hormones start packing their bags. I had an early menopause and I remember distinctly that at 40 I suddenly weighed more without seemingly doing anything different. If menopause is a possibility then it is worth having a blood test to check and then you can start thinking about managing your body (it comes to us all in the end).