So many difficult things about The Diet. Sam has a pretty limited range of foods as it is, so taking out an entire food group and our main staple from a second complicates things even more. Before the question was "is he getting enough nutrition?" Now it's "is he avoiding this loooong list of forbidden foods and getting enough nutrition? And is this huge, heavy burden of a special diet making enough difference to be worth it?"
On top of that, there's the questionable science of the whole idea. A recent review of the research showed no good evidence of improvement from a GFCF diet (http://www.ncbi.nlm.nih.gov/