I think it happens more than people think. I have a relative who thinks all carbs are created pretty much equal. So, she avoids bread and pasta, and just eats small portions of complex carbs, maybe once a day and, wait for it... has gut issues. Anyone who gives up bread, pasta and sweets (which happens a lot when people try to be "healthy") is at risk at becoming accidentally VLC (<50g of carbs) unless they make a real genuine effort to eat complex carbs. Non-starchy carbs don't count. They aren't net carbs — you burn more calories digesting them than you can extract energy from them.