Lots of people having success with all manner of conditions, including diabetes, high blood pressure, migraines, arthritis etc. etc. etc. on a high-carb, plant-based diet:
Success stories on 'Forks Over Knives':
https://www.forksoverknives.com/success-stories/
Regarding diabetes, specifically, I have uploaded a PDF link to various success and success-in-progress stories on FOK and MasteringDiabetes.
And here's a playlist with anecdotal evidence of great healing on a raw-food diet, based predominantly on fruit:
Louise's personal account is quite the turnaround:
In terms of general treatment of metabolic issues, Walter Kempner's work is very interesting. His diet intervention contained nothing but white rice, fruit, fruit-juices and ad-libitum amounts of refined sugar (Yup! The white stuff). If you're curious about that and other similar protocols, then Denise Minger's post is a good place to start:
https://deniseminger.com/2015/10/06...-a-call-for-some-evolution-of-thought-part-1/
I keep threatening to start a blog for my own high-carb journey, but have yet to get around to it. Fell off the wagon for a while, so maybe if for no other reason it would be a way of holding me accountable. Coffee seems to be my Achilles heel, as it sets of cravings for the 'wrong' kinds of foods