Just a few links to illustrate:
A recent study compared the Atkins (extremely low carbohydrate), Zone (low-carbohydrate, high protein), Ornish (very low fat), or USDA / Food LEARN (high carbohydrate / moderate-low fat) diet for 1 year. At the completion of the study, the women assigned to follow the Atkins diet lost more weight (~10 pounds average weight lost in 1 year) and also experienced metabolic effects that were comparable with or more beneficial than the other participants. Now however, it seems like researchers are bending over backwards to say that it was not about the low carb nature of the diet but simply the fact that the successful dieters stuck to the diet. Well maybe that is good? Atkins is easier to stick to?
I don't really know what to make of this one? Maybe the guy just had a stomach upset?
South Beach Diet associated ketoacidosis: a case report Whatever is going on, in the full paper
the researchers make some funny assertions, e.g. they say that a low carb diet produces insulin resistance, but there are studies out there (e.g. here and here) that claim that low carb diets improve insulin sensitivity!