I am just echoing what previous posters have said but I feel cross and sad that I am perceived as 'faddy' but people who seem to have no empathy or kindness, just a sense of superiority.
I was ill over many years, I had IBS, endometriosis, chronic fatigue, swollen joints, huge periods of depression, frequent respiratory infections, particularly, bouts of sinusitis, insomnia and, worse of all for me, bouts of itching when I would be up all night scratching my arms until I drew blood.
I was constantly at the doctors, saw consultants, took different medication.
I worked but in my own time battled to do anything but sleep.
A good friend who had given up gluten advised me to stop eating wheat and gluten, I was desperate but had nothing to lose by not doing so.
After about 3 weeks it was as though a switch went off in my body, I can only say it was as though I was fully awake, fully conscious. Bit by bit most of the symptoms have eased, though I still get every cold going.
Best of all, the itching has stopped! Blessed relief. I read about Joni Mitchell and feel she had the same reaction as me, I was prepared to believe in Morgellans.
The downside is the restrictions; no more eating without thinking, though as a vegetarian for 35 years I was used to that. There is gluten in so many products!
And the cost! It is expensive, my fruit loaf I have for breakfast is £2.50 - £3 a loaf.
But things are changing, so much more choice, bread and cake seem to be able to retain some moisture. I eat more healthily and have lost weight, I fully engage with my life and have regained my love of life.
I wish I had known when my mother was alive, I struggled to care for her through this fog of tiredness.
For though who say it is my 'choice', yes, it is. My GP offered to test me after I had stopped and results were inconclusive. I could eat gluten for 6 weeks then test again but I don't need proof. I know what happens if I slip up, I am unable to function properly.
(I wrote most of this last night but was very tired so saved it. I woke at 3am with most awful itchy arms, as I have just had surgery and can't use one hand this was so irritating. I don't know what I have eaten, I will need to look at all the ingredients of everything I ate yesterday. Some change will have been made to something and funnily enough the manufacturers don't slash "Now With Added Gluten!" on their products! 
So this essay could have been summed up as It makes me Ill so I don't eat it, it isn't done just to upset yo, it is bloody expensiveu and I am not secretly scoffing cake as most of the people other posters know are!!