Any facts or article on your claim? I think your source of info may comes from some chain mails that do not eat carbs & protein together.
However, I don't think you can have pure protein meals without carbs for vegetarian.

This mean whenever you eat wheat, oat, padi, barley it contains Carbs & Gluten.


Quote from Wiki:
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Gluten (from Latin gluten, "glue") is a protein composite found in foods processed from wheat and related grain species, including barley and rye. It gives elasticity to dough, helping it to rise and to keep its shape, and often giving the final product a chewy texture.
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