My Wife Is 46 And Has Been Told She Is

My wife is 46 and has been told she is experiencing pre-menopause, this has been going on for a couple of years now. She also suffered a heart attack about a year ago, has significantly changed her lifestyle, quit smoking, eating much better, increased exercise. She has been struggling with her weight, but has generally been able to loose or maintain it until the last 4 to 6 weeks when she's put on at least 15 lbs. What are your thoughts?
thanks