Separate Hepatic Steatosis from Obesity? Not So Fast

Nonalcoholic fatty liver disease. That’s the stigma-laden medical terminology for a condition also known as hepatic steatosis. This is a chronic disease that most often goes undetected, until it progresses to the inflamed state of hepatitis. But then it gets serious. The inflammation progresses to fibrosis. Liver failure or liver cancer can be the end result. Yet, many patients have no clue that this is progressing within their body until they reach an advanced stage. One of the key reasons is the difficulty healthcare providers have with the subject of obesity. Because separating nonalcoholic hepatic steatosis from obesity is usually not possible.

But What About Lean NAFLD?

Yes, many hepatologists will say that obesity is only correlated with hepatic steatosis. In so doing, they betray disinterest in obesity. Certainly, it is true that between 10-20 percent of patients with hepatic steatosis (or NAFLD) have a relatively normal BMI. They call this “nonobese fatty liver disease” or “lean NAFLD.”

Notice, though, the semantics of lean NAFLD and nonobese fatty liver disease. It conspicuously avoids the absurd contradiction of terms that “lean fatty liver” would present. And all of this reflects the implicit bias that obesity is a disease of size and weight – rather than the true definition of obesity.

While BMI is useful for studying the epidemiology of obesity, it does not define it. The World Health Organization says it succinctly:

Overweight and obesity are defined as abnormal or excessive fat accumulation that presents a risk to health.

So, regardless of BMI, if excess adipose tissue is contributing to hepatic steatosis, then a person has obesity, in addition to NAFLD. The one notable exception would be the rare condition called lipodystrophy. It is sufficiently rare that its true prevalence is unknown. In these rare patients, NAFLD is a problem, but they actually have a deficit of adipose tissue.

Obesity Care Is Foundational for Hepatic Steatosis

At ObesityWeek 2020, Professor Manal Abdelmalek told us that obesity treatment is the foundation for managing hepatic steatosis. A recent paper by  Vincent Wai-Sun Wong confirms that this is true even for people with a BMI below 25. They found that modest weight reduction with a very conventional lifestyle therapy was sufficient to bring a remission in NAFLD for many patients.

Why Does This Matter?

We have been struck by the degree of disinterest we find among liver specialists regarding obesity. Some will discount the value of bariatric surgery. In fact, we encounter many who are dismissive of obesity treatment broadly.

This is a shame, because it comes from bias about what obesity is – a disease of excess adiposity. Discriminating between “lean” and “obese” hepatic steatosis reinforces implicit bias about people living with a high BMI.

Overwhelmingly, the truth about hepatic steatosis is – just like obesity – that it is a disease of excess adiposity. Not size. Not weight. Just fat tissue that will harm a person’s health.

Thus, we must push bias out of the way to deal with both of these diseases.

Click here for the Wong paper, here for more on the value of bariatric surgery in NAFLD, and here for data on anti-obesity drug therapy.

Bronze Reproduction of the Liver of Piacenza, photograph by LoKiLeCh / Wikimedia Commons

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November 11, 2020