I suffer of Crohn's disease, which, as you may know, is a chornic inflammation of digestive tract. Few years back I went on a diet very similar to SBD - I only ate fruits, vegetable, eggs, nuts and yoghurts. It did wonders to my health. And that's also the reason I've now chosen to follow SBD, to both help my health, and lose some weight. Done properly, it's an awesome, super healthy way of eating, and it's sustainable for life.
I'm still on phase 1,5 (fruits, no grains) and I plan to stay on it for a long, long time. But that's just me, with my condition.
Never let a stumble in the road be the end of the journey.