Why aren't i losing weight? Am I gaining muscle?

gworksharder

Hi, so like most people on MFP I'm trying to lose weight but lately the number on the scale hasn't been going down despite my pretty intense workouts. I do a lot of biking (outside along the lakefront) and I'll usually go for 2 hours if not 2 and a half hours. On a typical bike ride, I burn 1000-1300 calories. The longest I've ever riden for was 3 hours and 12 minutes, and I burned 1714. I don't take very many breaks when riding (only the occasional stoplights or to change a song on my ipod). Otherwise, my bike rides are nonstop.
I usually ride 3 times a week, maybe more sometimes, and I definitely feel like my thighs have gotten so much stronger, but the number on the scale hasn't been going down...it's been going up!!! I don't know if this is the whole "muscle weighs more than fat argument" or "muscle is more dense than fat," but I'm getting pretty frustrated over this because I've been tracking calories and working out.
Yesterday, for example, I ate 1800 calories, and then I burned 1316 calories on a 2 hour and 29 minute bike ride. Because it was pretty late when I got home, I showered, ate a mango, and went to bed, so I didn't eat too many of those calories back (and I usually don't anyway). On days when I don't exercise, I try to eat between 1200-1400 calories.
My question is why aren't i losing weight? Is it because I'm gaining muscle? Am I eating too little on days I work out?

BTW I'm 18, 5'3, and currently 142 lbs. My goal is 130, but if I can look how I want to even with being at a higher weight due to muscle, I'd be okay with that.

Raeontherun

Eating too few calories. And no it's not muscle weight you are gaining.