I have been trying to quit sugar since 3 years almost. Yes, 3 years. Prior to that, I would have "No sugar" timeouts lasting for an year, then I would go on eating sugar for 2 months (Indian desserts, no chocolates, not a big fan of chocolate) and then again the timeout. And I was able to maintain that. Not from 3 years. I think I know the reason now. The body craves for sugar when one is stressed - really stressed. If one has trouble sleeping, one is forced to maintain "portion control" - which I think is utter BS, not to mention, stressful, then the body will crave sugar automatically. This is because the body goes low on serotonin when it is stressed and sugar provides that soothing effect by increasing dopamine levels in the body. One should clear off their mental blocks whatever they are, and take a deep deep breath and just stop worrying and the sugar control will become very easy. That's what I am trying to do and it somehow seems like a difficult task right now.