For most of her childhood, Jenna (not her real name) spent dinnertime staring at a plate of food that she refused to touch. She often was sent to bed hungry, or her parents caved and let her eat the only thing she could get down: French fries. Dinnertime hasn’t changed much for the 30-year-old dance teacher, who estimates that fries still constitute 90 percent of her meals. In the last 15 years, the only addition to Jenna’s diet has been pancakes, which she says took more than a year to work up the courage to taste. When she tried an orange for the first time at age 18, she immediately threw up.

But Jenna doesn’t restrict her diet because she loves fried potatoes—in truth, she doesn’t enjoy them at all. Jenna suffers from an unusual eating sensitivity, which has compelled her to eat almost nothing but French fries, cheese pizza, and spaghetti ever since she graduated from Gerber baby food as a toddler.

Over the past few years, researchers have been struggling to explain the origins and causes of the condition, which is sometimes called extreme picky eating, food neophobia, or Selective Eating Disorder (SED). Some psychiatrists attribute it to anxiety around past traumatic experiences such as choking on a food with a particular texture. Others suggest it could stem from an ingrained phobia of trying unfamiliar things, or liken it to the extreme sensitivity to textures and smells that coincides with autism or Obsessive Compulsive Disorder.