This. Instead of the (valid) notion of "you're still growing, you don't need to obsess about 2lbs" mindset, I would think it would be much better for her self esteem to tell her she's turning into an awesomely healthy muscle-building MACHINE! It's freaking awesome to gain 2lbs if it's muscle!
Originally Posted by Dr. Bork Bork
If she still has issues with a 2 pound weight gain, get her on the scale first thing in the morning after peeing, then have her drink a quart of water and get right back on. Voila! Instant pound or 2. Hopefully that will give her some perspective on the limits of scales for meaningful weight/size information.