Weight plateau

Recently I have lost 7 lbs in a month by excercising 4 times a week and limiting myself to1200 calories a day. Over the past 2 weeks it seems like I cannot lose any more weight. By the way I am 18 years old and weigh 136 lbs. For the past week I have been eating 800 calories or less a day and the weight still is not coming off. My question is what should I do to lose 3 lbs a week? (My goal is to lose 16 more lbs.) Another question I have is could I have a thyroid disorder? (I ask this because it has always been extremely hard to keep my weight down and it runs in my family.)

you are simply not eating enough. At only 800 calories a day you are setting yourself up for some serious health problems and you can damage your metabolism by doing that. The Bare minimum a female should consume in a day is 1200 calories. eating less when you've hit a plateau only makes it worst. You should increase you caloric intake a bit to get your metabolism working a bit more to get back on the track of losing. Try 1500 calories a day for a few days and see how things go.

But PLEASE eat something!

Just a fyi most people do not consider a 2 week weight loss stall a plateau. Most feel a month or more counts as a plateau.

Seriously, your body thinks its being starved - therefore it's holding onto fat. Eat at least 1,500 for a week and see how it is. Trust me - I used to eat like you're eating now, and the scale wouldn't budge. I only lost weight when I bumped up the calories. :)

Eat at least 1800 calories a day and continue to work out 4 days a week.  You need to revive your metabolism by eating much much more.  Even 1500 sounds too low for your age and activity level. 

Oh.. and depending on how tall you are, 136 lbs is not overweight for most heights. There is no way your body will let you lose 3 lbs a week..

I am right there with you (minus the exercise)...I have been losing weight and was pleased with my results...until about a month ago. I am now stuck at the same weight, give or take a half pound......no matter what I do, it's stuck. The advice others are giving regarding the eat more calories to boost the metabolism may be just what I need. I'm eating around 1350 cals a day.....wish me luck!

It's funny as I have a similar problem... though I'm older (52) and male... I started to diet, no, I started my lifestyle change on February 1st. 

Feb. I was easing into this 'thing' so I lost 5 lbs.  April I lost 10 lbs.  May I lost 9 lbs. June I lost 10 lbs, but as of today, July 31st I only lost 6-1/2 lbs this month, which was not a great surprise as I found my weight fluxuating up and down by 1-2 lbs almost every day.  By the end of June I lost 50lbs, and clearly my body and its metabolism has adjusted to the weight loss, and so I'm finding it harder to LOSE weight (w/o exercise... which I do find hard to make time for).  I haven't gotten discourage YET! LOL though the realization that I won't be losing 9-10lbs a month to more quickly get to my target weight of 170 by the end of September is annoying. <sigh>

thank you guys for all of your input! I just got the results back from a blood test and it turns out that I do have hypothyroidism. I will try to follow the advice you guys gave.