1400 Calorie Diet, Few Results - What Else Can I Do to Lose Weight?

I Had a Tummy Tuck and Lipo on my Thighs About a Year Ago. In the Past 6 Mo I Have Gained About 15lbs. I know that some of the weight gain was from not watching what I was eating or drinking. I'v gotten back into my normal groove of running 3-3 1/2 mi 5-6 days a week. I don't understand after a month or so why I can onlt lose 5lbs and then it seems to come back on. I take B12 shots weekly and am on a 1400 a day diet. High protine, drink a gal of water daily. At times I eat a protine meal bar (4g sugar,14g protine). What else can I do to get the weight off that I have gained???