In truth, none of us really "MUST" have carbs. We may crave them and go through withdrawal when we stop eating them, but carbs are not essential nutrients.
Sorry Brian, but the way you phrase this statement makes it a fallacy and feeds into propaganda by the low-carb establishment. Fundementally, this is a misrepresentation of what research actually says. I'd ask you to clarify why you have must captalized and quoted for emphasis.
You absolutely require some carbs and the fact that gluconeogenesis from protein is a central process to keeping a low-carb diet sustainable shows that carbs are necessary. The fact that glycogen stores sustain muscle function shows that carbs are necessary. The fact that if your Blood Glucose levels drop below a certain level your body will scramble to provide circulating glucose from glycogen stores in your liver shows that carbs are necessary. Heck, the fact that we actually work like demons to keep our BG between 70 and 120 mg/dl and that it is physiologically impossible to allow it to drop to 0, which would be the absence of any carbs, means that we require carbs.
The question is, do we require exogenous sources of carbs from our diet to supplement any gluconeogenesis from protein sources?
The answer, honestly, is that it depends.
Of course, many people have successfully brought their dietary carb intake down to very low levels, adhering very strictly to Bernstein numbers but has anybody ever successfully brought dietary carb intake to 0 and been able to sustain it at 0?
There's plenty of propaganda on both sides of this ongoing debate but unless the information we get is absolutely free of bias and questionable language then how can we honestly make the correct decisions that benefit us as individuals?