Scientists say there are two types of obesity and one is worse for our health

A new study breaks obesity into two distinct subtypes, each with its own impact on how our bodies function. The finding could not only lead to a more nuanced approach to diagnosing obesity-related health problems, but also lead to more personalized treatment modalities.

At the moment, obesity is diagnosed using body mass index (BMI) measurements, but the team behind the new research say this approach is too simplistic and risks being misleading Ignoring individual biological variations.

One of the newly identified obesity types is characterized by greater fat mass, the other by both fat and lean muscle mass. To their surprise, the researchers found that the second type was associated with increased inflammation, which has been linked to a higher risk of cancer and other diseases.

“Using a purely data-driven approach, we see for the first time that there are at least two different metabolic subtypes of obesity, each with their own physiological and molecular features that affect health,” says J. Andrew Pospisilik, a research epigenetics researcher in metabolic disease at Van Andel Institute in Michigan.

“Translating these findings into a clinically useful test could help physicians provide more accurate patient care.”

Using data from 153 pairs of twins collected as part of the TwinsUK research project, the scientists arrived at four metabolic subtypes that affect body mass: two tend to be lean and two tend to be obese.

These results were then verified in mouse models in the laboratory, using mice that were genetically identical, raised in the same environment, and ate the same amount of food.

These controls suggest that something other than diet, environment, and heredity is happening. A likely explanation is epigenetic markers – noncoding modifications to DNA molecules that alter how genes are read. Epigenetics is why twins with the same DNA code are not always identical.

“Our results in the laboratory almost copied the data from human twins,” says Pospisilik.

“We again saw two distinct subtypes of obesity, one of which appeared to be epigenetically triggerable and characterized by higher lean mass and fat, strong inflammatory signals, high insulin levels, and a strong epigenetic signature.”

From what researchers say so far, the second type of obesity — the one associated with inflammation — appears to be triggered by chance. That means these findings could also be useful in studying what’s called unexplained phenotypic variation (UPV), the idea that other factors beyond genetics and our environment make us who we are.

Scientists have thought about UPV for more than a hundred years, and this study indicates that epigenetics is linked to UPV.

“Today’s findings underscore the power of recognizing these subtle differences between people to guide more precise ways of treating disease,” says Pospisilik.

If two (or more) types of obesity can be confirmed in future human validation studies, then it follows that different obesity treatments—for example, dietary changes or weight-loss surgery—could have different effects depending on the obesity type. A whole new field of research has just opened up.

The researchers now want to take a closer look at the two identified types of obesity – which could lead to guidelines that doctors can use to diagnose them differently.

“Nearly two billion people worldwide are considered overweight and there are more than 600 million people with obesity, but we don’t have a framework for stratifying people based on their more precise causes of disease,” says Pospisilik.

The research was published in natural metabolism.