It seems like the underlying reason that all of these faddish diets seem to help diabetes is because they all result in a drastically reduced amount of carbs. As we know that it takes insulin to break down carbs/sugars, it is pretty obvious that a reduction in carbs is going to result in better BSLs and lower insulin requirements.
I don't personally understand how any diet could "heal" T1. T1 is, in most cases, autoimmune related so I just don't understand how a diet is going to change that. Again, reducing carbs will reduce insulin needs, but that's been known since the early 1900s.
I've made some pretty drastic dietary changes these past couple of months after I found out I was diabetic secondary to a genetic condition I was born with (congenital hyperinsulinism). I have reduced the amount of carbs I consume from around 220 per day down to around 80 per day. Obviously, I feel TONS better. My BSLs have come down significantly and, while it's hard, it works for me. Of course diet plays a role in all types of diabetes, but I have a really hard time when anything is sold as a "cure" for diabetes, especially T1.