For die-off and toxins, my top two recommendations would be Vitamin C and red clover. Another recommendation would be echinacea, though I've never evaluated that as a stand-alone supplement. For headaches ginger will help. The list is pretty long, maybe others can chime in with their favorites.
For stuff in the GI tract, depending on your situation, you might consider psyllium, bentonite, DE, and activated charcoal.
Keep in mind that vegetables contain carbs, so you're not really going w/out them. But it's healthy to avoid refined and processed carbs.