I'm new to this as well, add me if you'd like!

One suggestion on the future RMR test.

If you only have money for 1 test - get Bodpod or hydrostatic test for bodyfat %.

If money for both - do both at the same time, as they both need the same setup, morning after rest day, no food, good night sleep, no extra sodium day before (that's for BF test, not RMR).

Why?

You'll get your RMR reading. And it sounds like you are aware it will be low for where you likely could be. But you should not base any eating level on it, or you'll keep it low.

But, is it low for other gals your age, weight, height? Likely.
But, is it low for the amount of non-fat mass (LBM) you have? Unknown.

You actually could have correct RMR if you've burned off fair amount of muscle mass - which you likely have. But still unknown.

Now, if you have a BF test done, you can get an RMR estimate based on healthy body with your amount of LBM. Potential RMR is likely within 5% of that. Eventually, not likely right now.
And even if yours actually is lower to start with, you eat to what a healthy body would have - yours will become a healthy level.

So if you have money for both, that's best. Then the RMR just tells you where you are currently at, the BF% tells you were potential should be that you actually base eating level on.
If you only have money for one, recommend the BF test to base figures on.

Also, if you can look back over past records of weight gain, look at how much was gained and how fast.
Because frankly, if you think it was fat, the following must always apply.

Eating 250 over maintenance, even reduced maintenance at 800 calories - would take 2 weeks to see a slow 1 lb weight gain if it truly was fat.
Otherwise, anything else is just water weight.

So if you gained 4 lbs in 1 week eating a mere 200 more calories daily, do the math to see what it can NOT possibly be.
4 lbs x 3500 = 14000 excess calories / 7 days = 2000 calories eaten daily above maintenance if you truly think it was fat gained.
And if only eating 1000 - that obviously can't be true.

So always do the math, and my thought on looking at past records is to remove some of the fear based on past experience that is probably not right perspective in the first place.

Also think about this, that 800 requires whatever level of exercise you are doing.
Get injured and can't exercise or really sick, now how much must be eaten? Very scary thought.

If you already had a good BF test (not skin fold, not BIA scale), and you think you can get say a package deal for RMR, like one test now and one later - that might be good personally to see the increase.
But you would not actually base anything on current reading, so it's not like needed. Merely a data point to compare later, and curiosity.

4 lbs was merely example grabbed from air, but one I've seen mentioned. Actually it's usually mentioned in 2 or 3 days, after a weekend binge party. Proving even more it wasn't fat, because the binges weren't that awful.

But you have likely caused weight and fat gain not because of increasing calories constantly and steadily, but rather from short binges.
It's how someone say they gain weight eating 1200 calories and exercising, with logging accurately.
Huh no - 1200 may be your goal, but it's the day at 2000 that added fat. Do that repeatedly it doesn't increase metabolism back up, the body merely stores more fat in case the craziness continues.
So even looking at average over a great length of time, it could appear that 1235 caused this weight gain, again no, it was the binges. Truly eating 1235 daily would have been better, though doubtful enough either.

So in your case, how many times do you fall off the wagon and have a might free for all eating day, or huge meal you don't log because it's too unknown.

So you can't base anything on changes in scale right now, as you don't have a healthy body the math would normally be based on.
But you likely are eating more. Just not nearly enough more.

The coach has probably seen tons of folks that are indeed eating more than they think and they claim. Even using MFP decently and honestly will correct much of that. But weighing is still more accurate than measuring.

And bloat can be a problem, body not used to digesting more food and dealing with it.
That's why you increase slowly - 100 extra calories daily for a week, maybe 2 weeks. Then increase another 100 daily for another.

Experience. Some people can only learn through the school of hard knocks. Isn't required at all as proved by others that don't have to. Mental makeup differences. I know which group has less stress, less problems, better choices with better results though.

Also, experience, or reading or listening to the body as many will say, means you have enough knowledge to truly read it. Majority don't. Not only not enough background facts, but they aren't in touch with your bodies one bit. And even when they exercise, they are listening to music or pod cast or TV, and I'd wager since the mind can only truly think of one thing at a time, they are not listening to their body. They also aren't aware that deficiencies can take awhile to show up, vitamin, mineral or calorie for that matter. But when they do, the results are worse than if handled right from the start. And they don't know the symptoms to even look for in the first place.

Bear in mind so far you thought 800 calorie eating level was fine with level of exercise. And even if terrible logging and it was 1200, still that good?

You can recover though, here's one case study. Sadly all the info is after she came in, so no real tests prior. But still.

A similar case study was published by Jampolis (2004).
A 51 year old patient complained of a 15 lb weight gain over the last year, despite beginning a strenuous triathlon and marathon training program (2 hours per day, 5-6 days per week).
A 3 day diet analysis estimated a daily intake of only 1000-1200 Calories. (I'm sure this didn't include binge days that caused it)
An indirect calorimetry revealed a resting metabolic rate of 950 Calories (28% below predicted for age, height, weight, and gender). After medications and medical conditions such as hypothyroidism and diabetes were ruled out, the final diagnosis was over-training and undereating. The following treatment was recommended:

Increase daily dietary intake by approximately 100 Calories per week to a goal of 1500 calories
32% protein; 35% carbohydrates; 33% fat
Consume 5-6 small meals per day
Small amounts of protein with each meal or snack
Choose high fiber starches
Select mono- and poly- unsaturated fats
Restrict consumption of starch with evening meals unless focused around training
Take daily multi-vitamin and mineral supplement
Perform whole body isometric resistance training 2 times per week

After 6 weeks, the patient's resting metabolism increased 35% to 1282 Calories per day (only 2% below predicted).
The patient also decreases percent fat from 37% to 34%, a loss of 5 lbs of body fat.

Jampolis MB (2004) Weight Gain - Marathon Runner / Triathlete. Medicine & Science in Sports & Exercise, 36(5) S148.

Hi Ally, welcome to the EM2WL forums...happy that you are here! It sounds like you are on the right path to increasing your calories and weight training and getting your metabolism back to where it should be. Increasing slowly can help minimize the initial gains that some people experience. Here is a link to my story with EM2WL if you want to read it...I am actually 5 pounds lighter now than when I wrote it. I have had great success with increasing my cals/weight training and personally, did not gain any weight when increasing my calories. It does vary greatly from each person though, depending on your dieting history.

http://eatmore2weighless.com/jennys-inspiring-em2wl-success-story/

Also, feel free to check out the forums at EM2WL.com for extra support - most of the moderators focus on those forums, so it tends to be a little quieter over here, but we're always here to help and support you. You can add me if you want! Again, welcome!

ahhh someone speaks my language. Yes, it makes sense.

I mean i never thought about the "binge" days, and although my "binges" aren't the normal person's "binges", but they are higher in caloric value than what my body is used to in one day. So, yes i guess i have relaxed my "diet" in the past year and a half. I've allowed myself to eat that handful of trail mix, or that piece of cookie, or sugar free covered peanuts.... So i could have well gone above my normal calories in a given day, then back to crazy low cal because i might have felt guilty. Now, i had never thought about that and how that could have been the reason for fat gain.

BF, i actually made an appointment this coming monday (hydrostatic) which is actually not bad (75 dlls) so now i know that's truly what i need to start. I am thinking about doing that "indirect calorimeter" RMR test... coach didn't mention it but it would make sense to know that number in order to slowly increase based on whatever RMR i am at? is that how the process is started? or does the coach just pick an arbitrary calorie number then say "ok, now add 100 to that" .... ?

I am feeling a lot more hopeful, so with that case study you gave me, i see key words that ring a bell: consistency, right ratio of macronutrients for that particular person, supplementation and isometric exercise.

this coach, did mention how i needed to ease my body into cardio and resistance training. Call me incredulous but i feel like i could trust you more than him..... still questioning him and his ability to help me. I mean i don't want to end up throwing away money for every "trial and error" month... still...doubting him. I mean if you for example had been the coach "online" i would have said ok when do we start?

I guess it might have been a matter of communication style? i can be so judgmental. poor guy if he takes me as a client.

anyway, thank you so much for reading me and helping me. I truly appreciate the knowledge you've shared.

You add 100 calories to what you eat now on average.

So knowing the current RMR still doesn't change anything, because in 2 weeks it hopefully will be different.

What is missing from that case study is why some decisions were made.
Person could have been doing high carb with the thinking that is needed for her endurance cardio training, and needed more protein.
She might have had no gym access but lighter dumbbells, so iso lifting is way to use those and get something from it still.
As well as diet could have been pretty bad for nutrition being that low.
Plus her diet level, while indeed being proved out by her tested RMR, likely was higher during the time of complaint of weight gain, probably many spike meals - just not enough in a row to increase metabolism, only to add fat.

Just make sure you share your specifics with the coach too. I'm sure at some level there is disbelief that someone knows how much they are eating decently based on past experience, so he may be doubting you greatly.
If that assumption causes other decisions to be made a certain way, then things could be done not best. Still good, but like you said, could be a month of trial and error, and who likes to waste a month of time?!

So you getting a handle on accuracy for amount you really eat is good first step, so you can add 100 actual calories to that amount, you know your starting point.
Having BF% to know potential level of eating will be very beneficial to see where you are working up to eventually.
Current RMR will be interesting to see how bad a level you are starting at. And if done again later, how much you have improved.

And I'd also suggest that for workouts you have some measure of performance for what you'll be doing.
For instance, 60 min on treadmill going 4 mph isn't a measure of you, that's a stat. Now knowing your HR at start was 120 doing it but lowered to 90 after some weeks - confirmed progress.

Lifting is tad harder, because mere act of doing it well with form correct will see increase in weight that has little to do with strength, but eventually seeing weight increases proves out that strength is increasing.

And a body that is too underfed will be hard pressed to make improvements that require even more energy. So when you improve, you'll know eating level is better.