My experience is similar to DaisyEater's. It took years of eating gluten wholegrains before they caused severely debilitating IBS and other inflammatory problems.
Once I gave up gluten grains I put on a lot of weight because that cleared up malabsorption problems. I've had to adjust my calorie intake downwards.
I've now eliminated sufficient inflammatory crap from my diet and environment that I can thrive. I've never felt healthier and my energy levels are better than they were as a child. And I was a very active child compared to today's children.
However, it has to be said that I have a family history of allergy, atopy, food intolerances, histamine dysregulation and several auto-immune diseases, so I'm not Ms Average, thus I can't speak for someone who doesn't have these genetic disadvantages.
F 5 ft 3. HW: 196 lbs. Primal SW (May 2011): 182 lbs (42% BF)... W June '12: 160 lbs (29% BF) (UK size 12, US size 8). GW: ~24% BF - have ditched the scales til I fit into a pair of UK size 10 bootcut jeans. Currently aligning towards 'The Perfect Health Diet' having swapped some fat for potatoes.