I was on Crestor for several years and started on generic Zocor about two months ago due to a change in insurance (my new insurance would not cover brand name drugs without trying a generic first).  I am 39, my cholesterol problem is genetic (from both sides of the family), watch what I eat, exercise 4 or 5 times a week, and never gained an ounce on Crestor.  In two months I have gained 13 pounds on Zocor with NO changes to lifestyle (I've actually been working out more because of the weight gain, I can't get an ounce to come off).  In the past I gained over 50 pounds from being on anti-depressents and know what what drug induced weight gain looks like.  Zocor can definitely cause weight gain for some people.  I have an appointment with my doctor next week to discuss going back on Crestor.