I got on the SCD diet in 2007 after being diagnosed with crohns in the colon and having two massive rectal fistulas. After 8 months on the diet, both fistulas were healed up and all my symptoms were gone. The only meds I was taking was pentassa.
To this day, I have been completely symptom free and not had one flare. I still follow the SCD diet, but not as strict as before. When I first started the diet, I was following it with 100% fanatical dedication for 5 years. Only in the last couple of years have I strayed a little from the diet. When I say strayed, I mean like I will eat a sandwhich made with "non" legal scd bread a few times a week, or I will have a slice of pizza once or twice a month, or maybe I will have a sub from subway once a month, or some rice a few times a week, but other than that, I continue to follow the diet and I continue to stay away from all foods with sugar and all high carb foods like corn and potatoes, etc.
The secret to getting the diet to work is 100% dedication and no cheating with non scd foods. You might think eating potatoes are good for you because they don't bother you, but inside your gut, all you are doing is feeding the bad bacteria. Potatoes are high in carbs, which in turn convert to sugar in your gut, and this sugar just feeds the bad bacteria that leads to inflammation.