Arend is a guy most people love to hate.

He’s got a sleek physique, but it’s not the result of repeated trips to the gym.

“I put sugar in my coffee. I put whole milk in my coffee.  I eat bread. No problems,” he said.

But there could be a hidden danger in his seemingly enviable position.

Arend could be part of the growing number of thin people who are actually fat inside.

British researchers claim it’s possible.  They scanned 800 people with MRI machines to see where people store fat.

They determined a lot of people who look healthy on the outside are bordering on obese on the inside.

What’s more, internal fat found around the heart and other internal organs could be more dangerous than external fat that bulges underneath the skin.

“There are many people who are very lean who have severe heart disease,” UT Houston cardiologist Dr. Lance Gould said.

Dr. Gould uses Pet images to track disease caused by too much internal fat.

“Visceral fat in side the intestine is the highest risk.  So you can be kind of, pretty much not overweight and have a lot of visceral fat and be at risk,” Gould said.

The study also found people with normal body mass index scores can have surprising levels of fat stored inside.

The good news is, exercise and a healthy diet can burn away fat, be it inside or out.