My doctor told me I was fine to follow a modified Paleo diet and allow myself some wild rice and rolled oats (I love oatmeal). All the literature I had read advised against these, so for the first week I avoided them completely. This morning I decided to have to oatmeal, homemade, no sugar, just a little cinnamon. Within 5 minutes of eating it, I started to vomit. My body literally rejected the oats. Is this a common reaction? I'm shocked that after just a week without, my body seems totally adverse to anything else.
Firstly, whether or not to include oats in gluten-free diets for those with sensitivity is a controversial subject: some cultivars of oats contain the proteins that provoke a response in gluten sensitive and celiac people. If you were able to tolerate oats before, and wish to include them in your diet, perhaps you should consider getting 'certified gluten free'; oat seeds appear similar to seeds of wheat, barley and rye; cross-contamination between these is quite common.
Nevertheless, I have some doubts about whether ingesting oats - even if your were sensitive to them - would bring about such a spontaneous reaction. Did you literally throw up 5 minutes after eating them? Gluten ingestion causes a response in the intestine for sensitive people; I doubt that the oatmeal would have left the stomach so quickly. Its true that sometimes an irritant of which consumption has stopped will cause a more acute reaction if one reintroduces it, but then again I doubt it would be so fast.
Did you already have a sensitive stomach in the morning? Were you feeling queasy or (even lightly) nautious before you ate? Did you eat something problematic the night before? I think it might not have been as much a reaction to oats as food in general; also, oats have a lot of fiber, and also b-glucans which, in contact with water, have a slimy texture, and are lightly binding. Some people have trouble digesting oats; I personally always got the 'brick-in-my-stomach' feeling after eating oats before I went paleo. So perhaps, eating a food that can be hard to digest on an empty stomach (especially if, for some reason, you already had a sensitive stomach in the morning) could cause gastric upset.
In general, I think rice is your better option if you really need a grain alternative; if you really wish to consume oats, I would recommend treating them properly first (i.e. soaking them, which makes them easier to digest and to assimilate nutrients therein. I think this is one of the best resources to go to for properly preparing grains: http://nourishedkitchen.com/soaked-oatmeal-recipe/). You could also try experimenting with other pseudocereals such as buckwheat, or quinoa. Otherwise, if it's just a source of starch you're after, you can forego grains entirely and stick to starchy root vegetables, which are more nutritious, don't require such labour-intensive preparation as grains, are easier to digest and cannot be contaminated with gluten!
Last time I checked my blood sugar after eating oats (years ago now) it was 245. It seems our bodies don't know the difference between "healthy" oats and a donut. Same blood sugar reaction to both. I haven't had oats since then.
Do you have similar reactions to gluten-containing foods? Oats have two potential problems in that regard - they are frequently cross-contaminated with wheat in either the field or the processing plant, and they contain a protein similar to gluten (avenin). Some people sensitive to gluten are equally sensitive to avenin, some of them can tolerate it better.
Unless your doctor is really paleo-knowledgeable and supporting (as opposed to simply tolerant of your "weird" dietary ideas), I'd take any dietary advice with a grain of salt.
If it is a possibility that you are that sensitive to gluten, you may wanted to be tested while the tests still have a chance of being valid. The longer you are eating GF, the worse the tests perform and they aren't prefect to start with.
Also you may need to be strict about cutting boards, colanders, cc at friends homes, etc.
There's a brand of GF oats that are also low in avenin, grown in Montana: http://timtana.com/
It could be a mental thing. Vegans will vomit at the thought of eating meat. Maybe the killing of little oaties has upset you.
Oats do have some gluten, but I don't know how problematic they are. Maybe you should add some butter next time. (Or stick with white rice.)