When you ask people what they think the worst kind of fat is, more often than not, they’ll answer belly fat. It’s the hardest kind of fat to get rid of, the easiest to get, and the most pronounced out of all the kinds of fat. However, the true answer lies on the inside.

The worst kind of fat is liver fat. Studies show that high liver fat content is associated with type 2 diabetes, metabolic syndrome, and coronary artery disease.

A team of researchers led by Professor Iris Shai recently published a long-term study that focused on the impact of a Mediterranean and low-carb diet and exercise. The researchers from Ben-Gurion University of the Negev measured the impact that these things had with magnetic resonance imaging, or MRI scans in order to map body fat distribution. The study was published in the Journal of Hepatology.

For the study, fully-body MRI scans of 278 obese participants were used by the researchers to analyze the effects of 2 specific diets on their body fat distribution. The scans detailed their fat distribution before, during, and after the 18-month trial period.

The study showed that a low-carb Mediterranean diet significantly reduces hepatic fat or fat around the liver, heart and pancreas, compared to other low-fat diets with similar calorie counts. While overall weight loss between the diets had no significant difference, combined with exercise, the low-carb Mediterranean diet reduced the degree of central abdominal obesity or excess fat in the stomach area, otherwise known as belly fat. Abdominal obesity is a known risk factor for developing metabolic syndrome which is associated with elevated cholesterol and blood pressure and has been linked to an increased risk of stroke, heart attack, and peripheral artery disease.

Reducing hepatic fat or fat around the liver by 30%, along with moderate weight loss is an important part in reducing obesity-related health risks from a long-term perspective, the researchers of the study said. In addition to moderate weight loss, visceral fat or fat stored within the abdominal cavity was reduced by 25% and fat around the heart decreased by 11%. Fat in and around the muscle and pancreas was also reduced by 1 to 2%.

“Reduction in liver fat is a better predictor of long-term health than reduction of visceral fat, which was previously believed to be the main predictor,” Professor Shai explained in a press release. “The findings are a significant contributor to the emerging understanding that for many obese individuals, excess liver fat is not merely a sign of health risks associated with obesity, including cardiovascular disease and diabetes, but is likely also a cause.”

“Healthy nutrition, while also maintaining consistent, moderate weight loss, has a much more dramatic impact on levels of body fat related to diabetes, heart disease and cardiovascular disease than we previously though,” Shai added.

Researchers also found that reducing liver fat, and not just aiming for weight loss in the general sense, is more important when attempting to reduce the number of risks related to obesity.

The low-carb Mediterranean diet was also found to have lowered the risks of heart disease.