excersise calories

The 5 weeks prediction is bogus BTW take it with a pinch of salt unless your planning on eating & exercising exactly the same for 5 weeks it's pretty pointless 🤷‍♀️

If you followed the MFP profile set-up instructions, you will have set your "Activity Level" based on what you do other than intentional exercise, i.e., job, commute, home chores, non-exercise hobbies, etc. You pick a weight loss rate, and MFP calculates calories to cover that activity level, then subtracts calories (based on your weight loss goal rate) to give you a calorie goal. If you eat that, and do no exercise, MFP believes you'll lose weight at the rate you requested.

If you do 300 calories of exercise, MFP then expects you to eat those 300 calories, too; that should keep you at the same weight loss rate. This teaches the useful lesson that when we do more, we need more fuel, and when we do less, we don't need as much fuel in the tank (or we'll end up putting in long term storage, i.e., fat stores).

Since all of this is estimates:

1. Some people worry about exercise being over-estimated, so start by eating back a fraction of the estimated exercise calories. (I always estimated mine carefully, and generally ate them all back, all through weight loss and 4+ years of maintenance since. Still at a healthy weight, so that can work.)

2. The calorie goals (from MFP or any other source, including fitness trackers) are also estimates, based on statistical averages, so most people who've been successful here will suggest tracking carefully for 4-6 weeks (a full menstrual cycle for adult women not in menopause). Then, you can compare your actual average weekly loss rate to your targeted rate, and adjust eating if necessary to stay on course. (The premenopausal woman should compare weights from the same relative point in at least two different menstrual cycles.) MFP's estimates will be close for most people, a bit off (high or low) for a few, and quite a bit off for a very rare few: That's the nature of statistical estimates.

If using MFP as designed, not eating exercise calories is guaranteed to be wrong, because zero calories from exercise is false for any exercise. Letting exercise increase deficit may be OK if one has a very slow loss rate target for current body size, and not very high exercise calories (noting that calories can be high from either exercise duration or intensity). Someone who has an aggressive loss rate in the first place, and high exercise calories, is increasing health risks. Fast loss is not always a wonderful idea.

If someone wants not to eat back exercise calories, but instead eat the same number of calories every day, it would be a better plan to calculate a calorie goal using an outside TDEE calculator (which average in exercise activity across the week), and then set their MFP calorie goal manually. (There are reasons, but I won't belabor them here.)

OP, if you stick with a consistent regimen, you'll know fairly soon whether MFP's estimates are correct for you, or not. I'm about your size (5'5", around 9st 5), and I'd lose weight very rapidly (too rapidly for our size) on 1360 + exercise calories. That tells us nothing about you, however, because MFP's estimates are more likely to be close to what you'll see than someone else's personal results are. (I'd note that your 9st 10, at 136 pounds, or my 9st 5, at 131 pounds, is already well within a healthy weight range, so even if you want to lose more, it would be a good idea to lose it slowly).

So, keep going with your experiment, look at your actual average weekly results after you have at least a full menstrual cycle's worth of data, and you'll have your personalized answer. (Some people lose weight either extra fast or extra slowly in the first week or two. If that looks like it's true for you, drop those weeks, and use a couple of later weeks instead, to get to 4 somewhat normal weeks. You won't likely lose the same amount every single week, even if you eat and exercise the same - bodies are weird - but your average will stabilize if you're looking at it over several weeks).

Best wishes!