There could be many reasons why this could happen to you. One thing for sure is that losing weight is unique to everybody. Maybe your body is adjusting to the weight loss plan. Give it more than two weeks and see if the numbers on your scale will drop. When you're on the SlimFast diet, make sure that you follow the guidelines of the 1-2-3 (or 3-2-1, whatever it is) diet plan. Don't go over the allotted daily caloric intake; 1,200 for women and 1,600 for men. Also, balance cardio and strength training on your diet to make sure you're not just burning fat but also building muscles. The bad news is that SlimFast products are highly processed. They contain many added sugars and are produced from non-organic ingredients, contributing to weight gain.