With the restricted diets, compliance is extremely hard to achieve in a lot of cases. If you go to social events, work in an office, etc., it will always come down to being offered restricted foods and having to forcefully reject them. For many folks food becomes a religious thing and they decide(maybe not consciously) they'd rather die than change.

Fortunately my issues to date seem to be controlled with heavy vitamin D3 supplementation, so I don't have to do a hard restriction on anything.