She may be correct. The 70% ratio that many Americans eat may not be great, but 30% or 40% carbs seems about right for me. I see the no carb movement much like the no fat movement of the 80s.
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) 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. :)
You can try to counter the point by pointing out that there are ultra-marathoners who are keto. But my two counters against this are:
1) They generally still use some form of carbs during the race, i.e. sugar packets.
2) There is no world class sprinter / 5k / 10k / sprint biker / football player / soccer play that is keto.
So fine, you can make the argument that no carb is a better diet for an office potato with no exercise. But I would argue that bumping your carb intake up 25-40% and doing some exercise is going to lead to a much more healthy body and mind (many studies around on the benefits of exercise).
TLDR: The problem with office potatoes is being an office potato. You are better fixing it via exercise, vs trying to eat a weird diet that lets you stay skinny while an office potato.