YES the diets help. As said above, it does take quite awhile (6 months to a year). ease into it. I also changed other foods: all organic, no GMO, no processed, no artificial colors or dyes or flavors, no preservatives. I cut out corn and be careful of rice. I cut out sugar and artificial sugar. all pasture raised meat. I changed all cleaners to nontoxic. I had to change toilet paper, soap, shampoo etc... I even changed our environment to a calmer one. Sensory therapy including at home. A lot of one on one. My daughter was a picky eater in the beginning but now eats pretty much everything and will try anything. She is now able to eat gluten and diary etc... but I keep it at a limit. When I made these changes, there was at least a notice within 6 months. I did one at a time and eased into them. Her digestion got better and bowel movements got better. Her meltdowns eased. She started to talk and communicate more. It is a slow process, every child is different.

If you kid has Celiac disease you're supposed to go gluten free. About 1% of the population has this problem but the advertisers know the label "gluten-free" sells for now so you can expect more of it. Watch the movie "Safe" if you want to carry this belief system to the extreme.