We've been told that the target weight for a baby at two weeks is to get back to their birth weight. They tend to lose weight at first, and I'm convinced it's from all that meconium they poop out (I think there could be a market for this stuff as organic roofing tar).
We were pleasantly surprised when Gilly managed to get back to her birth weight at two weeks. It was a challenge getting her to eat during those first days at home, since she preferred to sleep rather than eat. Simon is a different story altogether. He was looking for something to eat as soon as he was delivered, and has been eating constantly since then. It was no surprise that he was 1.5 pounds over his birthweight at his two week checkup.
He is now affectionately known as "Chunky Monkey."