Eliminating white foods (pasta, bread, potatoes, rice, mostly) has really helped me, but I'm not 50 yet. Incorporating exercise into your day will help--not by driving to the gym for an hour, but by making the whole day active either by walking or cycling for transportation, also seems to help me maintain an even keel. I've drawn a 5-mile circle on a map with my house in the center. The idea is to ride my bike to destinations in that circle instead of driving my car. I'm not there yet, but I'm getting better.