The boy from the United Kingdom ate mostly fries, white bread and potato chips
Credit: High Angle View Of French Fries In Wax Paper By Sauce On Table

A teenage boy who subsisted almost entirely on fries, white bread and potato chips developed blindness due to his junk food diet, according to a new study.

The extreme case, covered by scientists from the University of Bristol in the journal Annals of Internal Medicine, occurred in a 17-year-old boy from the United Kingdom after years of a poor diet.

The teen, said to be a “fussy eater,” first started having health problems at age 14. After complaining about tiredness, his doctor ran blood tests that showed he had anemia and low B12 levels. He started getting B12 injections and was told how to improve his diet.

“The patient confessed that, since elementary school, he would not eat certain textures of food,” the study authors wrote, according to Live Science.

He chose not to follow his doctor’s recommendation and continued eating the same meals of fries, chips, white bread and processed pork that he’d been consuming since middle school. A year later, his doctor noted that the teen was experiencing some hearing loss and vision problems, but they could not identify a cause.

Two years later, at age 17, he was legally blind with 20/200 vision in both eyes — a condition that is permanent. The teen also had a B12 and vitamin D deficiency, low amounts of copper and selenium in his blood, high zinc and low bone density.

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The teen was given nutritional supplements to prevent his vision from getting any worse.

The researchers determined that the teen’s diet — both the junk food and the lack of nutrients — caused his permanent blindness. They said that while this case is a rare example, it could happen to other people as well, given the wide availability and cheap cost of junk food. They also believe it could be an issue for some vegans who miss out on vital nutrients like B12, which is found in protein and dairy.

“Our vision has such an impact on quality of life, education, employment, social interactions and mental health,” said Dr. Denize Atan, the study’s lead author and a consultant senior lecturer in Ophthalmology at Bristol Medical School. “This case highlights the impact of diet on visual and physical health, and the fact that calorie intake and BMI are not reliable indicators of nutritional status.”