I too was worried about this-as much as my body composition should matter more to me than my weight, I do care about reaching goal weight a lot.
Did some googling-
http://www.elitefts.com/documents/female_athletes.htm
8. Bulking up is calorie dependant. This means if you eat more than you are burning, you will gain weight. If you eat less than you are burning, you will lose weight. Unfortunately, most female athletes perceive any weight gain as “bulking up” and do not give attention to the fact that they are simply getting fatter. As Todd Hamer, a strength and conditioning coach at George Mason University said, “Squats don’t bulk you up. It’s the ten beers a night that bulk you up.” This cannot be emphasized enough.
http://www.msnbc.msn.com/id/11350094...aining-weight/
There's some evidence that exercise may boost your appetite . But don't fall into the trap of thinking that because you're exercising, it's OK to take in a bunch more calories, says Molly Kimball, a sports nutritionist at Ochsner Clinic's Elmwood Fitness Center in New Orleans.
Here's an example of why that's a mistake: "An average 150-pound person will burn about 300 calories during 30 minutes of pretty intense cardiovascular exercise," Kimball says. "This 300 calories, plus much more, can easily be consumed without realizing it with something as simple as a normal-sized baked potato or sweet potato or a six-inch Subway sandwich."
So what about strength training — can't extra muscle account for added weight?
While strength training builds muscle mass, it's highly unlikely that you've gained 10 pounds of muscle in one month, says Ivy. It's just not that easy.
Once I started hitting the gym and on the cardio machines a few days ago, I ate more too. I know that this does NOT have to happen-in the past, I would just buckle down and refuse to eat more, but nowadays I would rather take a longer time and walk around outside and not feel the appetite increase, than go back on the treadmill. I'll reserve my higher cal days for 1x a week kickboxing (I am doing this more as a stress outlet than anything else)