The simple answer is that if you're not losing weight, you're eating and exercising at your maintenance level of calories.
The science of weight loss is pretty simple. Every pound of fat that you carry on your body is 3500 calories of stored energy. And the only way to get rid of the excess fat is to force your body to utilize the stored energy. So in the most basic sense, fat loss boils down to creating a calorie deficit by eating fewer calories than we burn off in a day through everyday living and exercise. Creating a calorie deficit is the only
way to force your body to tap into the calories/energy stored as fat in your body.
Of course, this is a very basic and simple explanation and there are many variables that affect every individual's weight loss - water retention, health conditions, stress levels, hormones etc etc. And I believe that not all calories are created equal and we won't lose as well on a diet of Krispy Kremes as we will on one of chicken breast, brown rice, and broccoli. But at the end of the day, yep, it's all about calories in vs calories out.
I think we all run into a problem when we try to quantify how fast we thinkg we should be losing based on metabolic calculators and exercise calculators. First of all, none of us know how many calories we burn in a day unless we've been tested in a lab. Studies show that calculators based on age, height, weight etc are off by up to 700 calories per day - not insignificant!
We have a metabolic test called the BodyGem in the gym where I work that measures O2 output (O2 is the fuel of metabolism) over a period of 10 minutes to determine resting metabolic rate. I don't trust it 100% - but the important point is that I've gotten readings on women ranging from under 1000 calories per day RMR to over 2500! That's quite a range!
So my point is that you believe that you're burning over 2500 calories per day, but ... how do you know that? You could be burning more or less -- short of some fairly advanced testing, it's just a guess.
The same thing is true for the exercise calculators. They're averages based on lab testing done on normal weight college students, from what I've read. And the read-outs on exercise machines are notoriously inaccurate.
So - my opinion is - forget what the numbers say you SHOULD be losing. It's an exercse in frustration and futility. The ONLY important thing is how your unique body reacts to your calorie input and exercise.
If you're not losing or gaining weight, then you've discovered the maintenance level of calories and exercise for your body. In order to kick it back into fat loss mode, you'll need to create a calorie deficit by eating fewer calories or burning off more with exercise - preferably both.
My advice is to track your calorie input for a few weeks. Keep track of how much and how intense your exercise is over the same period of time. Then weigh yourself. If you're losing 1 - 2 pounds per week, great! Stay where you are. If you aren't, then you need to ramp up the exercise and/or cut back on the calories (not below 1200, please!). Eventually you'll discover what works for your unique body - and it may be different from anyone else!
Lat year I talked to a researcher who runs a weight loss lab at a university - the kind of place they lock you into for months on end and monitor everything you eat and all your exercise. He said that they have NEVER had anyone who hasn't been able to lose weight once they hit on the magic numbers for calories and exercise. We all have that 'sweet spot' of calories and exercise that works and it's up to us to figure it out.
So ... my suggestion is to forget what you think your weight loss should be doing and instead keep track of how your body reacts to what you're eating and how you're moving. And then adjust accordingly.
BTW, for what's it worth - you and I started out at pretty much the same weight. At 257 pounds, I started out at 1600 calories per day, and by the time I got to where you are now, I dropped to about 1400 (went down to 1200 once I hit 199). And that was with about 90 minutes of exercise per day. That doesn't mean it's what you need to do, of course ... but it's what my body required to lose the weight. And through trial and error, you'll be able to figure out exactly what works for you too.