Wow - our body types sound very similar! I am 28 years old, 5'8" with a larger frame and can "hide" my weight well too. I am heavier now, but at one point I was thinner. When I'd be right around 170-180 pounds, I would always get stuck. And most of the time, I would go in the upward direction. I think my body was just "comfortable" at that weight, and maybe yours is too. I had to work really, really hard to get past 170 pounds. For us taller girls with heavy bone structures, 170 pounds may sound like a lot, but it's not too far from a healthy weight (I think the upper edge of healthy for our height is 165). That being said, the only time I got down to the 150s was when I did alot of weightlifting. Weightlifting and building lean muscle will help speed up your metabolism because a pound of muscle at rest burns more calories than a pound of fat or other tissue. I would spend about an hour for 5 days a week weightlifting, followed by about 30 minutes of cardio (walking on an incline, elliptical). I tracked my calories and ate about 1600-1800 a day. I know it sounds unrealistic to work out that much, but building the muscle and speeding up my metabolism made all the difference. As a result of about a year of hard work, I went from a flabby 200 pounds and a size 14 to a fit, lean, muscular 155 pounds and a size 6. I let myself go and then I had a baby, so I'm now back up in the 200s but trying to get back there someday! I think the forums are a great place to find support - just don't give up!
Here's to being "Thin by Thirty"!
Starting Weight: 235.8
Current Weight: 218.6
Pounds Lost: 17.2
Goal Weight: 150
Weeks at FitDay: 8
Deadline: July 17, 2012 - My 30th Birthday!