I just like to add that I'm not automatically against the diet, just think that all things need considering
I don't think boab and I are here to defend it necessarily - we're each conducting N=1 experiments based on some challenging thinking from Gary Taubes and others.
I find it very hard to understand why we evolved such a crappy fueling scheme as the carbohydrate/insulin/glycogen model - that at best gives you a few hours of activity before you have to eat again, or fall over - whilst sidelining a much more efficient, cleaner, and longer lasting fuel supply - in the lipid/ketone model.
Which leads me to think - perhaps our fixation with carbohydrate has in fact flipped us all around. That in fact, we evolved to primarily use the lipid/ketone system and subsist on minimal quantities of carbs (berries, nuts and leafy stuff - perhaps tubers), and our carb/insulin/glycogen fuel supply is actually an emergency supply for rapid response such as flight or fight, which requires fast acting energy input that only anerobic chemistry (glycogen) can provide.
The large quantities of carbs in the typical western diet has to be processed by insulin. If it's not used immediately for fuel, it's stored in the fat cells for later, and we get a bit fatter. Whilst this is going on, stored fat is preserved and you are fueled mainly by dietary fat and glycogen.
If you've got obese, and want to lose body fat, you need to sideline insulin as much as possible, so as to free up the mobilisation of stored fat. Several forms of diet do this indirectly - even just cutting calories does, because proportionately you cut more carbs than anything else. Removing sugar and refined carbs also helps, as these give the biggest insulin response.
The problem with cutting calories but still eating a high carb diet is, you get hungry. Equally, if you exercise more - you get hungry. I've definitely found my appetite suppressed on a low carb diet, so it's much easier to run a calorie deficit. At the same time, my blood sugar is stable (5.0mmol/L - nearly all the time, it's the same) and insulin is sidelined - except for processing a little glucose from my liver, to my brain.
And as of yesterday - it would appear I can ride a 200km winter audax on next to no carbs too.