MASLD/MASH Roundtable: Defining and Assessing Obesity
Three eminent hepatologists expert in the diagnosis, treatment, and management of MASLD and MASH start off a series of roundtable talks on these conditions by reviewing changes in the definition and assessment of obesity--a key issue in the increasingly prevalence of fatty liver diseases.
Robert Fontana, MD, is a professor of medicine and director of the Transplant Hepatology Fellowship Program at University of Michigan Medicine in Ann Arbor, Michigan. Manal Abdelmalek, MD, FAASLD, is a professor of medicine and director of the Metabolic Dysfunction Associated Steatotic Liver Disease (MASLD) Clinical Research Program at Mayo Clinic in Rochester, Minnesota. Juan Pablo Arab, MD, is associate professor of medicine and the inaugural director of Alcohol Sciences at the Stravitz-Sanyal Institute for Liver Disease and Metabolic Health at Virginia Commonwealth University (VCU) Health in Richmond, Virginia.
Clinical Practice Summary
MASLD Assessment: Experts Discuss Proposed Obesity Definitions Beyond BMI
- In this MASLD/MASH roundtable, JP Arab, MD, described proposed definitions that pair confirmed excess adiposity with organ dysfunction for clinical obesity; preclinical obesity lacks organ dysfunction. He noted that MASLD may indicate organ dysfunction even when BMI is normal.
- In referral practice, Manal Abdelmalek, MD, said she asks about changes in waistline and weight distribution because routine waist measurements are not always feasible.
- For GI clinics, Robert Fontana, MD, suggested considering waist circumference and waist-to-hip ratio. He noted that current treatment trials did not use the proposed definitions.
Transcript
Dr Fontana
Well, good morning everyone. I'd like to welcome you to this expert round table on the diagnosis and management of MASLD and MASH in 2026. And this educational activity is being sponsored by the Gastroenterology Learning Network. So my name is Bob Fontana. I'm a professor of medicine in the Division of Gastroenterology and Hepatology at the University of Michigan. And I'm delighted to have two good friends with me today on our podcast, Dr. JP Arab from VCU and Dr. Manal Abdelmalek from Mayo. So JP and Manal, would you mind introducing yourselves and a little bit on your background?
Dr Abdulmalek
I'm Manal Abdulmalek. I direct the MASLD Clinical Research Program here at Mayo Clinic Rochester. I'm also professor of medicine in the division of gastroenterology and hepatology. Happy to be here.
Dr Arab
And I'm JP Arab. I'm director for alcohol science at the Stravit Sanyal Institute for Liver Disease and Metabolic Health. And I'm also an associate professor of medicine at the Division of GI. So thank you for the invitation.
Dr Fontana:
So I can't think of two better experts to talk about the intersection of MASH, MetALD and ALD, which is on everyone's minds today. So maybe to kick things off, we could start with the big picture, which is we have a problem with obesity in the United States, and as gastroenterologists, we frequently see it playing out in MASLD and MASH. So I was recently reading that the definitions for obesity were recently proposed a change in early 2025. Do you want to give me your take on that? What are we doing with the definitions? Are they better? Are they better prognostically, diagnostically? JP, any thoughts on what's being proposed?
Dr Arab:
Yeah, so basically the Lancet Commission tried to move us beyond the BMI alone. Now is this clinical obesity, which basically requires some evidence of organ dysfunction. So plus adiposity that needs to be confirmed either by waist circumference or body composition versus preclinical obesity when you don't have these end organ damage. So in our field like MASLD, it can be considered an organ dysfunction. So BMI alone may be missing, for example, when you have sarcopenic lean patients with MASLD. So this new definition trying to be more objective in how we are assessing the metabolic dysfunction.
Dr Fontana:
So they're kind of broader, right? It's not just a single parameter of BMI. So in other words, you can have dysfunction and yet your BMI could be minimally elevated or even normal. So Manal, you're at Mayo Clinic, you're a referral center. If I were to come see you as a patient, do you measure waist circumference on every patient coming to your clinic? Is this something we should start to think about?
Dr Abdelmalek:
Yeah, I think this is certainly something we should start to think about. Do I measure waist circumference in my clinical practice? The answer is no. There's just not the allowance, the feasibility, and potentially some relative inaccuracy sometimes in measuring waist circumference. However, I think this change is a very important one and one that was meant to come for many years because we've known that BMI alone is such a poor surrogate of organ dysfunction. As an alternative to waist circumference, I do ask some probing questions. I will ask patients intentfully, have they noticed a change in their waistline? Have they shifted how they carry their weight? And invariably patients will point exactly to their abdominal region. Some will rarely point to their hips, but the majority will point to their abdominal region. And what's interesting is this change in the obesity definition is so very important when it comes to our seeing patients of Asian, Hispanic ethnicity where BMI is just a very poor surrogate of end organ injury, but they will readily let you know that yes, they may have gained a very minor amount of weight, but the distribution of that weight is predominantly truncal.
Dr Fontana:
So it sounds like we all think this is probably going to improve the field, but it'll be a little bit of a slow go from the start. And certainly the clinical trials that we use to treat patients with the current medications were not at all based upon this new definition. So my sense is it may take a few years before it sort of filters down into clinical practice, but certainly something if you're revamping your clinics to think about adding in a simple measurements, you get a tape measure and you can easily do waist circumference and waist-hip ratio. If you can do a BMI, you've already got the height. And so I want to demystify this. It comes from the Endocrine Society. It's not a sophisticated measurement. I mean, a waist circumference and a hip. They do talk about using objective measures as JP mentioned, like maybe a DEXA scan to look at the amount of adipose tissue.
But in a run-of-the-mill busy GI office, I'm not sure that would be a parameter that anyone would have. So I guess we'll have to wait and see where this goes.
