This study references another one that took a year to show signs of speedup.
Also shows it's not just metabolism, it's total body burn which is beyond metabolism.

http://www.myfitnesspal.com/blog/heybales/view/reduced-metabolism-tdee-beyond-expected-from-weight-loss-616251

You'll notice here the ones that had the effects of slowdown, while eating at lab measured suppressed TDEE, started speeding already, but study ended at 3 months of biggest slowdown time.
Would it have kept going up causing a deficit to eventually occur eating at same amount?
Would they have kept increasing the eating level based on new lab measured TDEE?
What would the speed have been eating slightly more than suppressed TDEE, until back up at potential TDEE?

I've never seen a study except the one they reference that had timelines, because genetics, severity, other stresses, ect, all are going to effect that.

There are people purposely eating low enough to slow their TDEE down all the time, not in a diet, just a way of life to benefit from hopeful longevity animal studies have shown. They don't speed back up and start losing weight, they stay suppressed.

The only other thing I've seen are case studies, based on a person coming in with an issue, getting current stats, changing something, and getting end stats.
So accuracy of what got them there doesn't exist beyond people's memory.
But those show promise.
Here's one such example that only looked at RMR reading, so this was metabolism, but you can bet that if RMR went down, the other parts of TDEE already went down too since they happen first to protect the RMR as best it can.
And you can probably discern the actual weight gain came about by binging often enough fat was added, because TDEE was so low.

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.
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.

Ok, here's the awesome response I got from Kiki! Super interesting!

I'd recommend that she check out our "resources" page if she hasn't already. It's jam-packed with info.

http://eatmore2weighless.com/faqs/resources/

EM2WL research is based on a combo of several studies on starvation response and human biology. Then we give obviously general guidelines with the "adapt to your situation" disclaimer lol. Most people need LONGER resets, but on rare occasion someone would do "ok" with shorter. Longer typically does more good than harm, so we find it best to err on the side of caution. This doc from our resources page shows that the process could take 6 to 9 months -- beyond what we recommend.

http://www.7layerliving.com/wpcontent/uploads/2010/01/feastorfamine.pdf

And the biology of human starvation volumes indicated at least a three-month rehab (eating double the cals) after the starvation experiment ended.

http://eatmore2weighless.com/the-starvation-experiment/

The vids that we have on the resources page from Layne Norton suggest that the reset should actually be AS LONG as the diet was. Yikes! Lol

The reason that there are so many different numbers is that we're not just talking about "weight" but also replenishing any other vital nutrients/minerals/functions that may have been affected by the "budget" of low cal dieting. So the commonality...the longer the reset, the healthier the person will be for it in the end.

But we know that most people will not be willing to wait as long… So we set our standard where it is. We originally said 4 to 6 weeks because we thought that people would not commit to more than that, LOL & we just wanted to get as many nutrients in there as we could. But we found that we were doing the Fam a great disservice shortening the length of time, so we have recently extended it… And still encourage them to go as long as possible. The choices so individual to the circumstances that each person is under, it's really hard to have one blanket guideline. So if she was not dieting for that long before and truly feels that her body is ready, it will be a personal call to move forward. At the very least she could test the waters and if her body does not respond continue resetting."

I think you've done awesome increasing your cals and it's been great for you to see how much your body truly burns! I know you've learned so much through the process - you can definitely cut and still eat a lot of food. I can totally see how it's a chore to eat that many calories. I know you don't want to decrease your exercise because you enjoy it so much, but one option would be to take out some of your cardio so you're not getting such high burns, and then your TDEE would be quite a bit lower - and much easier to support nutritionally. Thanks for sharing it all with us!

It would be pretty easy to set up an online form that would fill in a google spreadsheet with people's responses. The issue would be choosing the questions. I'm a social scientist so I'm really interested in research and understanding patterns in people's experiences.

I do appreciate the need for longer reset periods. I'm thinking long term now, like 6 months cutting, 6 months at maintenance for several years to get to my goal. This pattern would mean I might need a couple of years to get to my goal weight since I probably need to lose about 40-55 lbs still. I can see how most people would have trouble being patient for that long.

I think your body responding so quickly to the increase of calories by obviously increasing it's burn is a good genetic sign. Hopefully.

It could also mean it's fast to adjust - either direction.

Except this time, you aren't dumping down to bare bottom levels - just a minor deficit.
So the stress shouldn't be anywhere near the same.

And as recommended many places, every 6th week, you take a diet break and eat at current TDEE for new weight.
2 weeks would be better, as it seems to be found it takes about that long for hormones to reset better.

I think you have a good activity factor for your level of exercise, so no matter what your BMR drops to you'll get a decent TDEE estimate no matter what Scooby says.