Mary, I feel for you, when I turned 40 I gained tons of weight, and thought I was eating healthy because I ate low fat, lots of bagels, bananas, etc. Well I was starving all the time. I finally read a book called the Glucose Revolution that explained the glycemic index. I have diabetes in my family and am very sensitive to high carb, sugary foods. It changed my life. I lost weight and was not hungry at all. I now eat mostly seafood, chicken, some lean steak, tons of veggies, and complex carbs.
Also, I do lots of weight lifting, it builds muscle which helps keep the pounds off. If I do too much cardio and exercise with my heart rate too high, I just burn all the glucose in my body and crave carbs for the rest of the day...took me a long time to learn these tips but it has really helped.