You can, but you don't have to. Combining high protein with low fat can be dangerous (it's called rabbit starvation, and if you google it, you'll find what causes it, they symptoms, and how to avoid it - basically by eating plenty of low-carb veggies and/or some fat with your carbohydrates).
The symptoms are pretty yucky (vomiting, diarrhea, dizziness, nausea, severe headaches...), so the simplest advice is that if you feel sick on low-carb make sure you are eating more veggies and/or fat, along with plenty of water (but there's no reason to guzzle the stuff. 2 to 3 quarts is plenty for most folks - and that includes liquids like milk, soda and even coffee and tea).
I do use whey protein and protein bars (though it's hard to find either that aren't too high in carbs), but I tend to use them more for occasional convenience (not as an every day food)
On the plus side, they are quite convenient for quick meal/snacks or roadtrips.