I didn't suffer from joint pain, but I did have other issues that cleared up when I stopped grains. Maybe these will give you an idea of the range...
4 days grain-free: noticeable improvement in acid reflux problem (it was a 6 antacid per day problem)
2 weeks grain-free: last antacid (it's now been about 9 months without problems)
2 months grain-free: noticed decline in asthma problems
4 months grain-free: off asthma medications (this has been a problem since my teens)
On the other hand, even a TINY cheat (i.e.: a martini with wheat-based vodka in it) and I'm tight-chested and/or wheezing within a few HOURS.
So... a range of problems and a range of healing times. I do hope someone can chime in more specifically about joint pain for you, but I suspect it may vary a lot between people.
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