When eating healthy becomes unhealthy

Orthorexia nervosa is an eating condition you probably haven't heard of.

It describes the harmful obsession some of us have with good eating, and it can lead to malnutrition and social isolation.

You or someone you know may be affected, so what happens when healthy eating becomes unhealthy?

Health blogger Lauren Went became obsessed with what she ate.

"It was at that point where I was afraid of simple, normal food," she says. "I would think a sandwich is bad to eat because it had bread. It's safe to say I became afraid of certain foods."

It got so bad she stopped going to some things with friends in case she got tempted by unhealthy food. When she did give in, she felt like a failure.   

"The guilt made me feel like I was as big as I was at the start."

But how can we comprehend why people getting so obsessed with good eating? Thirty-one percent of Kiwi adults are obese. There are 671 million obese people in the world. Many of them are them are trying to lose that weight, often through healthy eating. But some go too far.

"It's essentially people who have an unhealthy obsession with healthy eating, so they're spending an ordinate amount of time researching their food, preparing their food, thinking about food," says dietician Angela Berrill.

Ms Berrill is describing orthorexia nervosa – a condition that can lead to malnutrition.

"It can also lead to people being very socially isolated, so afraid to potentially go out in a social situation when they haven't prepared the food themselves."

Of course we all get food guilt after hoofing down, say, ice cream, so how do we know the difference between normal guilt and full-on orthorexia?

"Certainly it's that socially isolating component criteria for orthorexia as well as that food guilt shame as well," says Ms Berrill.

If you're worried you or someone you know has orthorexia, she says you should see your doctor and a registered dietician.

Watch the video for the full Story report.