Maybe I can shed some light on this subject. I am currently on the no sugar diet. When I first went on it I did some research and I found that sugar was more addicting than cocaine and found that sugar puts you more weight on than fat! My first night without sugar was horrible as I had previously been eating around 70g A DAY! I was breaking out in sweats, I was angry and all I wanted was a hit of sugar. I also suffered from mild headaches and fatigue. This lasted for around 4 days, but once I got over it I found so much more energy and I felt brilliant.
Honestly, if you replace your "white sugar" with "natural sugar" such as berries, fruits and natural yoghurt you won't be as down as you are still getting sugar. You should also know all the different names for sugar, I think there are over 50.... that are found in diet sodas and pasta sauces!
If you have any time on your hands, I recommended watching 'Fed up 2014' you can find it somewhere on YouTube as is very informative.
Hope this helped