person A: My friend and I both did a low-carb diet last month. She lost 8 pounds. I gained 2! 
person B: Wow_comma_ great for her! I am confused as to how you ended up GAINING though!
person A: I dunno. Water weight? She looks so good now. I'm really envious. 
person B: Well_comma_ keep at it and you will get where you want to be. It really just comes down to how many calories you take in vs. how many calories you burn per day.