Being Obese and Metabolically Healthy

For most people, carrying excess weight, especially around the abdomen, is a sign of present or future health problems. However, this is not the case for everyone. For some, being overweight does not carry with it the ordinary risks of high blood pressure or cholesterol. For these people, a relatively new term has entered the medical lexicon: metabolically healthy obesity.

For a person to be labelled obese, they must have a body-mass index (called BMI for short) of 30 or higher. Those with a BMI of between 25-29.9 are simply called overweight. A person’s BMI takes both their weight and height into consideration when formulating the rating, and that is where some problems arise. You see, BMI often incorrectly identifies muscular, fit people as being overweight or obese because the muscle is more dense than fat and it also weighs more. Yet the difference between the two could not be any more stark. Whereas fat converts blood sugar into yet more fat and stores this energy, muscle burns up and eliminates blood sugar.

In most cases of obesity, a patient will demonstrate unhealthy changes in their metabolism. Blood pressure will increase, as will levels of cholesterol. These two events in themselves carry with them a whole host of health complications. Damage to the arteries can occur, and a person also begins to develop a resistance to insulin, a hormone that the body produces in order to control blood sugar. All told, a typical obese person is at an overwhelmingly higher risk of heart attack or stroke, the development of type 2 diabetes, or another debilitating health condition.

Yet for some reason, some people who are obese manage to avoid all the complications. They maintain an otherwise unhealthy weight for a long period of time, yet on examination, present medical stats that are on level with people who are in the healthy weight range. That is to say, their cholesterol levels are in check, they have normal blood pressure, and they show no signs of blood sugar issues. Generally, these “metabolically healthy” obese people share several traits in common with each other:

  • they have a waist size below 40 inches in men, or 35 in women
  • they have a normal insulin sensitivity
  • and they are in good physical fitness

It is possible that genetics may play a role in this anomaly? A person’s genes determine where fat is stored. And if it is directed towards the thighs, hips, or arms, these people will carry far less health risks than those obese people who carry the extra weight around their abdomen. It is also possible that these individuals are genetically protected from insulin resistance. Yet neither of these states are necessarily permanent ones. For instance, a person who appears to fall into the category of  metabolically healthy obesity may do well in various medical tests, but as they age and their physical activity level declines, this stable state could easily reverse itself.

Recognizing the concept of metabolically healthy obesity has several implications. It makes possible safer decisions regarding weight control procedures such as bariatric surgery. Used in cases where changes to diet and exercise do not appear to have a great enough effect, these options seem suitable for people for people with metabolically unhealthy obesity. Yet in cases of  metabolically healthy individuals, the risks would appear to far outweigh the benefits.