I consume way too much sugar, but since I don't have the will to cut back, I though I'd look into other solutions starting with my coffee, which brings us to...
The Sugar Cube Faceoff
Reigning Champion White Sugar Cube: 1700 kJ/100g
Contender Brown Sugar Cube: 1680 kJ/100g
I may actually consume enough sugar cubes for that to make a difference, but even I have to admit that this experiment is pretty much a dud. Back to the drawing board!