What is Normal Weight Obesity?

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What is Normal Weight Obesity?

It sounds like an oxymoron - if you are a normal weight, you are by definition not obese, right? It is genuinely confusing. This is why some say the term is a misnomer, preferring terms such as "Normal Weight Metabolically Obese" or "Normal Weight Central Obesity". (I have my own opinions that I'll share later.)

What everyone is trying to get at is that a substantial number of the people who's weight is normal according to the BMI have many of the symptoms, signs, and risk factors associated with obesity.

They even have excess fat, but not in a place where it's especially visible. They have what is called visceral fat, or central adiposity -- fat that is in the abdomen around the organs, rather than under the skin where it is more obvious.

The worrying constellation of things associated with so-called Normal Weight Obesity are the following:

  • Excess visceral fat (usually measured by waist circumference or waist-hip ratio)
  • Elevated blood glucose (prediabetes or diabetes)
  • Insulin resistance
  • Elevated insulin in blood (hyperinsulinemia)
  • Elevated blood pressure
  • High blood triglycerides
  • Low HDL cholesterol ("good" cholesterol)
  • Increased inflammation

This combination of things is often called metabolic dysregulation and is very similar to metabolic syndrome. There is no doubt that people who have some of these signs are at an increased risk for heart disease, diabetes, and possibly other chronic conditions such as Alzheimer's Disease.

It is also worth mentioning that this list is very similar to the one that low-carb diets have been shown (time and time again) to effectively address.

By the way, people who are in this situation have been shown to have a higher risk of heart disease, and of dying for whatever reason ("all-cause mortality") than people who are overweight or obese!

So yes, this matters very much.

Normal Weight Obesity is Common!

A lot of people reading this probably assume that this condition is relatively rare. This is probably because we have been told time and time again that BMI is the be-all and end-all of weight and health. The truth is that somewhere in the neighborhood of 25-30% of people with a normal BMI have central obesity and/or metabolic dysregulation.

What Can be Done?

Cutting carbs can definitely help lower the risks inherent in the metabolic syndrome, and this doesn't necessarily mean eating a very low-carb diet. Just cutting way back on sugar and refined carbohydrates can do wonders for a lot of people.

Should we Call this Condition Normal Weight Obesity?

I give this an emphatic "no"!! This is one of the most confusing labels ever. Almost every health organization defines obesity according to BMI. Using the BMI, you are either obese or you are not and your weight is normal or it's not. Combining the two seems totally ridiculous to me.

Furthermore, we have some perfectly good descriptors for what they are labeling "obesity". The terms "insulin resistance" and "metabolic syndrome" and "prediabetes" have been around for quite some time.

Doctors know what these terms mean, and lay people are coming to know them as well. These things are correlated with obesity, but they are not obesity! There are people who are overweight or obese who do not have these problems at all (so-called "metabolically healthy obese"). It seems crazy to me to invent a confusing term when we could just say that the person is insulin resistant or has metabolic syndrome.

Personally, I think that this comes from the history we have of stating over and over that obesity "causes" many problems, when often this has not been proven at all. It's more the case that obesity is associated with many problems.

It could very well be that the real problem in a lot of cases (example: heart disease) is metabolic dysregulation, not the overweight or obesity itself. But because we have had it drilled into us by the media that obesity causes heart disease, when we find out that people who are not obese have the same problems, we turn around and call it "normal weight obesity"! This is totally backward! Let's please not do it!