Regardless of who you are, where you go, and whom you meet, you can easily find people who will tell you that obesity is bad for your health. It is true that obesity has been associated with a host of serious diseases like diabetes, hypertension and heart diseases. It is also true that obesity is a precursor to diseases like arthritis, gall stones, infertility, cancers and many other serious ailments.

Worldwide, the incidence of obesity has been steadily increasing over the last couple of decades. Earlier, obesity was considered to solely be a malaise of developed countries. In US alone, for instance, around 40 percent of the population is grappling with the problem of obesity. Now, the condition is becoming increasingly common in many developing countries too.
Several studies carried out in the recent past have identified a set of people who the scientists call as “metabolically healthy obese individuals.” These individuals may have a BMI of more than 30, but do not suffer from any of the problems that generally plague obese people. Their cholesterol levels are normal, their blood pressure is not elevated and they show no signs of insulin resistance.
Difference between an obese individual and a metabolically healthy obese individual
So, what makes a metabolically healthy obese different from other obese people? Scientists have observed that when a person is obese, fat initially deposits in the adipose cells present in the subcutaneous tissue. But as more and more fat accumulates in these cells, the mitochondria — the "powerhouse of the cell", remember? — present in these cells are damaged. The mitochondria are no longer able to convert glucose into energy. Moreover, these cells can even lose their ability to regenerate. As no new fat cells are formed, these cells bulge to their capacity and ultimately die. There is inflammation around these fat cells and when the cells burst, the fat gets accumulated into vital organs like the liver, heart, blood vessels and skeletal muscles — tissues where it is not meant to accumulate, posing a serious danger to the person's health.
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In contrast, in metabolically healthy obese individuals, which comprise around one thirds of all obese individuals, the fat remains in the adipose cells present in the subcutaneous tissue and does not spill over to other tissues or organs. Therefore, these individuals continue to enjoy a good state of health even though the fat content in their body is much higher than normal.
In Metabolically Healthy Obese, The Adipocytes Continue To Regenerate Normally
Dr. Jussi Naukkarinen, a research scientist at the University of Helsinki carried out a study in Finland to find out what differentiates an obese individual from a metabolically healthy obese person. He, along with his colleagues, carried out a study on 16 pairs of identical twins (six male and ten female) of which one twin was obese while the other was not. The average weight difference between the two twins was around 40 pounds. The researchers chose the twins to understand the effect of genetics, environment and other factors in the development of obesity.

The 16 pairs of twins were divided into two groups. In the first group, the obese twin had higher cholesterol levels, higher blood pressure, impaired sugar and insulin levels and a lot of fat deposition in the liver. In the second group, although the BMI of the obese twin was much higher, the other parameters remained similar to that of the lean twin. The researchers examined the fat tissue of all the participants.
The examination threw up some interesting findings. The researchers observed that the number of adipose cells present in the subcutaneous fat tissue of the healthy obese twins was 11 percent more than the adipose cells present in the lean twin. However, in case of the unhealthy twins, the number of adipose cells was 8 percent less than the number of adipose cells present in their lean twin irrespective of the fact that the fat content in their body was much higher.
The researchers have opined that the proper functioning of the mitochondria is imperative for the regeneration of new fat cells. In the unhealthy obese twins in the study, as the mitochondrial functioning was impaired, they were incapable of regenerating. This accounted for the lower number of fat cells in these individuals. On the contrary, in the healthy obese twins, the mitochondria were found be functioning to their optimal capacity and new fat cells were being regenerated. So, the excess fat was accommodated in the new adipose cells in the subcutaneous tissue without spilling out and moving to other tissues.
According to Dr. Naukkarinen, anti-inflammatory medicines protect the mitochondria from damage. The cells are able to convert glucose into energy and do not show insulin resistance. Excessive consumption of alcohol and eating a fatty diet which creates spikes in the levels of glucose and insulin in the blood has an opposite action on the cells.
Metabolically healthy obesity is a transitional phase
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To support their view, they say that metabolically healthy obese are generally young individuals. As they age, they become unhealthy. Only one- third of metabolically healthy obese continue to remain so throughout their life.
On the basis of these studies, many people feel that BMI is not an accurate indicator of a person’s health status. Other parameters should be defined to find out persons who are at a higher risk of developing diseases like diabetes, hypertension and heart disease. However, all said and done, the bottom-line remains that all obese individuals, metabolically healthy or not, should try to lose weight as it is difficult to say who among them runs a high risk of developing diseases.
- “The ‘Healthy Obese’ and Their Healthy Fat Cells,” by Anahad O’Connor, published in the New York Times on October 9, 2013, accessed on November 24, 2013
- “You CAN be fat and fit: Scientists say that 'healthy obesity' exists and that physical fitness is more important than BMI,” by Fiona Macrae, published on August 31, 2013 in the Daily Mail, accessed on November 25, 2013.
- Photo courtesy of Steve Baker by Flickr : www.flickr.com/photos/littlebiglens/8295846970/
- Photo courtesy of Steve Baker by Flickr : www.flickr.com/photos/littlebiglens/9973428966/