From a practical standpoint you are correct; however, it is very difficult to have a zero carb diet, so I don't think this theory has been 100% tested. At least

From a practical standpoint you are correct; however, it is very difficult to have a zero carb diet, so I don't think this theory has been 100% tested. At least, this is the impression I got reading this opinion paper. (http://ajcn.nutrition.org/content/75/5/951.2.long http://ajcn.nutrition.org/content/75/5/951.2.long) I think even most ketogenic specific diets aim for around 5% carbs. Some other aspects of carbs seem to be not fully investigated, such as the effect of dietary fiber's role in nutrition. While not "essential" (http://jandonline.org/article/S2212-2672(15)01743-8/abstract http://jandonline.org/article/S2212-2672(15)01743-8/abstract) it seems to play a mostly positive role. (If only to prevent constipation...) At this time, I'd think "fad" of any ketogenic diet advocate that has little vegetable consumption. But as the first link states, "most of the current low-carbohydrate, weight-reducing diets advocate the consumption of low-carbohydrate vegetables". "Eat more veggies" has been a mantra of dietary advice for a while. :)