Diabetes diet does get hard to figure out like you said. I know I need to watch mine better, but I do like you said, know what spikes me, and the only way is to keep a food diary to figure out what what food is doing to you. I am lucky if I remember 3 days ago what I ate, let alone what I ate 3 months ago. In America we get an A1C blood test every three months, because that is what they say gives the average blood sugar readings. So yes if someone is going to try a new diet, like you suggest they need to try it for at least 3 months to see if there is a change. Also people need to drink more water.