I took 20mg of Lexapro for about 8 months and gained 30 pounds. During that time I trained for and ran a marathon and was continuing to gain weight. I have always been an athlete and healthy eater and have since stopped Lexapro in the last 5 weeks but still have no improvement in weight. I go to the gym 6 days a week/1.5 hrs and eat about 1500 calories a day. This has been a horrible experience and I would suggest that unless you absolutely have no other option, stay away from Lexapro.* In the first month, it made me lose 10 lbs because I had not appetite but even when I wasn't eating much, the weight started increasing every single week.