Even if you have a slight frame, 5'6"/120# isn't you carrying extra weight. I'm 5'8", with a medium build, and I was bones-sticking-out-skinny at 125#. Personally, I'd reassess what your goal weight is.

Lift weights! I was not getting results at all with just chronic cardio. But when I started weights the inches started coming off. Good luck!

My suggestion, less cardio, more high intensity interval training.

You already have some great answers. Now, I am an old granny but I am 5'4" and when I was fit 125-130 was a very lean-and-muscular weight for me. So I think Jenni's point is worth your thought.

Also, unlike you I was very fat when I started. Still, I had already lost 30 pounds by early September and I've lost at least 5" from my waist since then. I am strict no-wheat but I eat a modest amount of local honey plus heavy cream in my coffee AND I eat home-made extra-fat yogurt daily.

I told you those things because losing weight on real foods is more like staying on a sidewalk than walking on a line--it's as bad to eat too little as it is to eat too much. It's as bad to exercise too much as it is to exercise too little. Make sure you understand the down-side of heavy exercise and starvation.

For me, it's definitely important to eat varying amounts from day to day--a lot one day, less the next and once in a while nothing.

EDIT: You should check out the new post at Paleo Solution

amputation maybe?

If you're a fit 5'6", 120, how do you have any inches to lose? Seems to me like you're an ideal weight already. I throw my lot in with the others saying maybe you need to reassess your goals.

I'd also second the suggestion to lift weights if you aren't already. A lot of my female friends mistake a total lack of muscle definition for having extra fat. I lived in a 5th floor walkup with a girl once who wasn't able to take the trash out because her arms were too weak to carry it down the stairs. She went to the gym 4-5 times a week, but when I suggest she maybe start lifting some weights, she said she didn't want to end up with "Madonna arms". I love the girl, but that was one of the stupidest things I've ever heard

My point is, a lot of girls seem to be scared of lifting weights and bulking up. If you're one of them, I would tell you to get over it. Muscle is good, and doing reps a couple times a week won't turn you into a muscle bound bodybuilder.

Stop exercising; eat more food.

If you're only now cutting out sugar, my guess is you have been on a traditional reduced calorie diet (technically called a semi-starvation diet). The first thing you have to do is get your body out of starvation mode by letting it know the famine is over. That will cause your body to return to a normal metabolism level (instead of the reduced metabolism level produced by semi-starvation diets).

Once you've returned to a normal metabolism level, you should get on a full blown paleo diet. Cut out the carbs, eat vegetables, fruit, and meat (including the fat). You'll start losing weight on this diet without any exercise.

Now, you can add back in the exercise. It will make you hungrier, but since you'll be eating when you're hungry (and not counting calories) you won't over eat. Nor will you under eat, which would cause you to go back into starvation/lowered-metabolism mode.

You said you cut out gluten, but are you still eating other grains?

I am 5'7" weighing 140. I am muscular and wanted to lose weight, too. But when I started working out, I realized that losing inches was the way to go. It is impossible for me to lose any more weight but it is VERY possible to lose inches. Look to paleo to lose those inches and you will succeed. It took me about a month to see real results with paleo, though. Good luck:) Use bells and you will see results.