I believe Dr Tom O'Bryan claims it takes between 3 - 6 months for someone with intolerance to stop making antibodies after gluten exposure. I've also heard statistics that gluten intolerants ingesting gluten remain at an elevated risk for death for about 6 months. I'm relying on my memory here, so this could be off. Sean Croxton interviewed Dr O'Bryan twice for Underground Wellness and covered this topic well.
Some people heal faster than others. The last time I indulged in stupidity and ate wheat on purpose I developed Dermatitis Herpetiformis. Dumb of me--I deserved it. When I realized what I'd done I stopped the wheat and will *never* do it again. It only took a few weeks for it to go away, but I was also working in a panic to reduce inflammation and heal my body from my stupidity. For other people it can take over a year to get rid of the autoimmune problems and other glitches caused by gluten.
To get over the addiction to gluteomorphins that some people experience can take more than a week. I've even read accounts of it taking a month before cravings finally stop.
For a person living on a healthful diet and who has an intact gut lining and robust gut flora, I suspect everything goes back to a healthy norm much faster than for those who have spent years ingesting the SAD.
The real answer is it depends, but I think a good approximation is 6 months.