gotta lose the mighty middle!!!

I'm 51 and my mighty menopause middle is relentless. I gained about 25 pounds after menopause with no change in my eating habits. Every pound is located in my midsection. Don't want to get diabetis, and heart disease which are associated with weight carried in that part of the body. Tried everything, and have not been successful. Help!!! Any suggestions for a diet that will work. Have a knee problem which prevents me from treadmill or any aerobic activity. Really need to find a diet plan designed for the menopausal metabolism!!
waiting to hear from you.