I've done it, the first week was like hell as my body attempted to convince me I was on the verge of starvation despite being a fat fucker
Past the first week I then became miraculously full of energy, lost loads of weight and didn't really crave sugar that much. However you have to stick rigidly to it as I found any relapse was fatal. It was interesting to see how much my body ruled my food choices though and that it wasn't necessarily 'willpower' or 'being hungry' that made me pick stuff - the craving was insane.
I went on holiday to Spain, wanted to eat tapas, didn't stick to the diet - am sat here now shoving Christmas cake in my gob.
I followed the rules basically of Michael Mosley's book - no refined sugar, no cake, no biscuits, puddings, chocolate, honey, dates, juice, smoothies.
Very low carb - no pasta, rice, potatoes, bread etc
No breakfast cereals
Fruit was OK (but veg better) except grapes which apparently don't have enough fibre to help you manage the sugar. Interestingly my DM is now diabetic and has found her blood sugar shoots up after grapes but not other fruit.
Idea was after you have achieved goal weight you relax the v low carbs and do a more Mediterranean style diet - lots of veg, fruit, oily fish, small amounts of carbs, still minimal sugar.
Sadly the lovely tapas ruined that for me. Maybe after Christmas I'll try again.