You need to look at your diet.  Write down everything you're eating and try to figure out what you can cut out.  If you can cut 500 calories a day, you should lose a pound a week.  Most of us eat a lot more calories than we think we are.  Make switches from higher calorie to lower calorie foods.  The Eat This, Not That books and web articles can be helpful.

I'm like you.  I lost 45 pounds, then hit a plateau several months ago.  I'd like to lose 5-10 more, but it isn't really necessary.  I'm well within healthy weight limits.  I started running and have only lost two pounds since I started running 5 months ago.  However, I know that I've also increased the amount I'm eating.  I get really hungry, especially after long runs.  When I look at the calories I'm eating, I can see where I could cut some, but at the moment I don't really care enough to deal with the hunger that would follow.  I try to eat healthy, most of the time, but I know I could do better. 

Is there any way to split up your running into two different sessions per day?  It sounds like that might be difficult with time constraints, but balancing the exercise over a span of time keeps metabolism going and certainly assists in weight loss.  Also, strength training is always a good idea and even simple floor routines will help with building abdomindal muscles that improving running performance.

Wishing you the best of luck!

Have you tried interval workouts (also known as speed work)? I'd never done speed work before I started training for my first half-marathon, but within a couple of weeks of incorporating just one day of intervals and one tempo run, I started shedding pounds like crazy. I was also completely ravenous, but I managed to keep that under control by focusing my eating on more healthful foods.

There's research indicating that your body continues in a relatively high calorie-burning state after an interval workout, so you continue to burn the calories after you're done running as well as during. As with everything on the Internet, however, your mileage may vary.

Don

It depends a little on how formal you want to be about it. One option is to run fartleks (Swedish, I think, for "speed play" and a source of endless entertainment). With those, you just run arbitrary distances at arbitrarily faster speeds. If you're out for a run and you're feeling good, maybe you sprint all-out to the next light post, then take it easy for a while. Then you sprint from the corner to the mailbox a block away. It's all what you feel like doing when you feel like doing it.

On the more formal front, you can do structured interval workouts. Initially, you might run a one-mile warmup, then run a quarter mile at slightly-faster-than-5k speed. You'd then jog/walk for a couple of minutes (or for another set distance) and repeat the process several times, then finish with a one-mile cooldown (total: about 3.5 miles, give or take, depending a  bit on whether you use distance or time for your recoveries). At first, you might do four such repeats (written on most training plans as 4x400m). Recovery intervals are usually based on time or distance (say 90 seconds or 200 meters). After you've spent a few weeks doing 400m repeats, you might either increase the number of repeats or increase the distance of each repeat (say 800m, 1200m, one mile). You're usually shooting for specific target paces for each repeat. I like to use the McMillan Running Calculator to estimate the appropriate training paces. Just enter a recent finish time for a race and it will calculate the appropriate training paces for all kinds of workouts. It looks intimidating at first, but it's a really useful tool.

Do one of those each week (not more -- they really stress your body and if you try to do too many, you'll break) and maybe pick up the pace of one other run so that it's "comfortably hard" -- a so-called tempo run -- and you'll both get faster and burn some extra calories.

Don

Just came across your post and  felt as though I had written it! Same thing with me- lost 35 lbs this year, working out 5-6 days a week, and haven't lost a pound for months. Fluctuating, like you said, and my weight is always within a pound or two. I started focusing on improving my running as a way to feel like I was making improvements since I wasn't seeing weight loss improvements. Like you, I was very intimidated to try to run faster. I was very focused on running further. I just recently started trying speed work like Don had mentioned. I am doing 2 minute intervals on the treadmill. It is very challenging and actually seems to make the time go by faster. (I hate running on treadmills but sometimes with the early dark outside, I have to.) I'm curious if you continued to do the speed work and if it helped you lose any more weight. It's been a few weeks since your original post so am very curious about your progress!

Like you, I read this and thought it was about me.  I've been running consistently for a year and half, I initially dropped about 45 lbs and then...nothing for about 8 months!  Very discouraging, and like Rennmaus, I have already made the major life style changes in my diet.  I'm faithful with weight watchers, and even they are baffled by my lack of progress. I write down everything that passes through my lips.  There really isn't anywhere else that I can cut out of my diet.  I've even gone as far as getting my thyroid checked, but the only thing my doctor was able to say is that I just have a very VERY slow metabolism.  Grrrr.  But I keep plugging along and I feel great knowing I got a run in.  I still need to lose about 40 lbs but in the mean time.  I live by the motto that "You never regret the run you did, but you almost always regret the run you didn't do."