Took me about 5 years to heal my metabolically deranged body, so I believe it can be done. Everyone will be unique and some will heal faster than others. The key is not to have some arbitrary timeframe in mind (ie I want to be healed in 4 months) just live the paleo lifestyle and the rest will follow naturally as one's own body dictates. We abused our bodies for decades to get so damaged and true healing can take years to accomplish, it's not a race. I was overweight, had digestive issues, was T2 diabetic, never pooped properly, had allergies, high blood pressure and a host of other issues, now my doctor calls me the picture of health and he is looking closely and utilizing paleo principles in his practice now.

I think it's possible. I had bad insulin resistance and couldn't look at rice or a potato. Now I eat both alot and often. I'm starting to think that using heavy resistance training to empty glycogen stores and then ramping up starch refeeds over a period of time is a great way to "teach" the body how to properly use glucose since it really needs it immediately after that kind of energy expenditure.

On a hypothalamic/leptin level, I really don't know how long it takes or the processes involved in reversing the glycation and oxidation of the receptors, though I'm sure healing needs to happen here just as much as the insulin resistance at the muscle cell level. Just eating paleo and keeping the toxins out will do this.

I believe that it's possible, but I wouldn't begin to try and guess a timeframe. I think that what's important is to restore insulin sensitivity and to address the organs that support digestion & blood sugar handling, especially the gut and liver. Re the first, I think exercise is probably the most important -- not chronic cardio, but something that gets the causes your muscle cells to require glucose (e.g., HIIT or resistance training).

Re the second, the key is getting the right nutrients, healing the gut, and reducing stress/cortisol; I think Chris Kresser's 9 steps to perfect health is a great approach.

I definitely believe it is possible.

I had hypoglycemia before going Primal. Now I can fast for up to 20 hours easily.

Here's a recent article that you may find interesting on the topic of metabolic impairment:

http://www.gnolls.org/2407/when-satiety-fails-why-are-we-hungry-part-4/

You are probably short term healed in the sense that you've found a balance again in nutrients stored in your body and available for use. If you start hitting the high carb low nutrient pattern you will probably store fat very quickly though as you don't yet have a lot of reserves to take up the slack.

In a word - as long as you are eating right, you are healing it gradually, and how long this takes depends on many factors, such as your innate strengths and weaknesses and the extent of the decline from health you were previously at... as soon as you stop, you are reversing the work you have done, and a little bit of this is okay as long as it doesn't go beyond two steps forward, one step back. If it doesn't; if you maintain at least two steps forward, one step back, you are gradually making progress.

It probably doesn't help to look at people as either healthy or ill as the truth is we are only ever at one point along our own personal scale at any point in time. Better to continually reevaluate your position and work to create as much improvement as you can without destroying your quality of life through stressing over it too much.

Make positive changes, stick to them as much as possible, use your own judgement to evaluate your position and be happy knowing you're constantly learning and growing.