Besides the ever-so-annoying belly fat, there's also a much more "invisible"—but just as harmful—kind of fat: one that sits around our internal organs. What causes this, and is it possible to get rid of it? A new study has some answers.
Too much sitting down can build 'invisible' fat, says new study.

For one thing, we need get off our tushies, and pronto! Sedentary time correlates directly with how much fat we build around our organs, according to the new study, which was published in the journal Obesity.

For another, we need to exercise. The research shows that sitting has an even more harmful effect for those who don't work out enough.

You might be tempted to think, "Thank you, Captain Obvious," but actually, few people are aware of the importance of body fat distribution and the fact that the fat around our organs puts us at serious risk of chronic illness.

The new study was led by Dr. Joe Henson, research associate at the University of Leicester in the United Kingdom, who comments on the importance of the study, saying, "We know that spending long periods of time sedentary is unhealthy and a risk factor for chronic illnesses, such as type 2 diabetes and heart disease."

"Likewise, the amount of fat deposited around our internal organs may also predispose us to these diseases," Dr. Henson says, and he's not the only one. In a previous study we reported on, visceral fat inside the abdominal cavity was shown to raise the risk of heart disease.

Using MRI scans to measure fat distribution

Dr. Henson and his team used MRI to scan 124 participants who were likely to develop type 2 diabetes. The MRI scanners examined the fat around the participants' livers, as well as their "invisible," inner fat—which is also known as visceral fat—and total abdominal fat.

Using accelerometers that were placed around the participants' waists, the team also measured how much time these people spent sitting down over the course of 1 week.

The researchers considered age, race, and ethnicity, and the levels of physical activity in their calculations.

They found that the more time people spent sitting down during the day, the more visceral and total abdominal fat they had, as well as having more fat around their liver.

Importantly, this link was the strongest for those participants who did not meet the public health recommendation of 150 weekly minutes of moderate-intensity physical activity.

"Using MRI techniques and physical activity monitors we have shown that the more time spent sedentary, the stronger the association with higher levels of internal and abdominal fat. This was particularly so if the long periods of sedentary behavior were uninterrupted."

Dr. Joe Henson

Physical activity may reduce internal fat

"Our findings also show that reaching the government's target of 150 minutes of moderate-intensity physical activity may offer some protection against the harmful effects of prolonged sedentary time."

Study co-author Melanie Davies, a professor of diabetes medicine at the University of Leicester, also comments on the study, saying, "Lack of physical activity and being overweight are two risk factors associated with type 2 diabetes."

"However, the effects of prolonged sedentary time and whether physical activity can play a mediating role by reducing fat deposits on internal organs remain unclear," she says.

"This research," adds Professor Davies, "starts to shed a light on any connections between the two by using MRI to measure the distribution of fat in an individual's body and analyzing that in relation to their activity levels."

She concludes, "The next step would be to examine the impact of regularly breaking up prolonged sedentary time upon internal fat levels."

—Ana Sandoiu