Does Obesity Always Equal Unhealthy?
You can’t tell if someone is healthy just by looking at them. And that includes people in larger bodies.
Obesity is currently diagnosed using the body mass index (BMI) scale. But BMI isn’t the best marker for health, and lots of non-scientists already know this.
This is effectively demonstrated using athletes.
“Rugby bronze medalist Ilona Maher is classified as overweight according to BMI. See?? She doesn’t have too much body fat, so we can’t assume BMI tells you everything about health.”
The reason that example works so well to convince people that BMI doesn’t equal health is because you gave them someone they’re primed to respect: muscular, powerful, and strong.
Our minds don’t automatically assume that they would be unhealthy.
Now what about someone with visible body fat who is not an elite athlete? Someone who looks the part of our everyday “fat” American.
What would your response be to finding out that the individual with lots of body fat was metabolically healthy?
This essay is about cases where obesity and metabolic health coexist. I integrated a few open-access papers on the subject alongside my nutrition-obesity pre-doctoral training to convince you that you can’t tell if someone is healthy by just looking at them. And that includes people in larger bodies.
Metabolically healthy obesity (MHO) is a really interesting topic in my field because it throws a wrench in our assumptions about obesity as a disease. MHO means that an individual has the BMI ≥ to 30 kg/m2 but doesn’t have many metabolic problems. For example, they might have healthy blood sugar, cholesterol, and blood pressure despite carrying higher levels of body fat. There’s not an official way to diagnose MHO, but most research on it will score people based on how their bloodwork looks (for more on MHO, read this article).
Depending on how strict the cutoffs for MHO are, the range of people with MHO is between 6-60%. Honestly, the 60% is pretty high and I’d err on the lower end of the estimate. But this is still significant when we consider 1 in 3 adults have obesity in the US. We may encounter people that have MHO (including ourselves) in daily life. Yet in the public’s opinion, everyone with obesity is a ticking time bomb for a heart attack (I’m looking at you, kinesiology bros and fitness influencers).
Let’s get some of the questions out of the way:
What are some reasons that someone would have MHO versus metabolically unhealthy obesity (MUO)?
This is still under investigation. But one thing that is apparent is people with MHO tend to store less fat inside and around their internal organs. If you’ve ever heard “thick thighs save lives” yeah, actually. People with MUO end up storing fat in places that cause issues for their health. MHO folks are able to store fat in places that don’t get in the way of metabolism (like the thighs and butt).
There’s also new research that people with MHO have healthier muscle and fat cells than people with MUO. I warn you, it’s a complex paper, but it’s well-done science!
Are the long-term health outcomes different between MHO and MUO?
There is some research comparing people that had MHO vs MUO vs no obesity (they call those “lean” people). For outcomes including type 2 diabetes and cardiovascular disease, in general the risk is highest for MUO followed by MHO and lastly the lean people.
But wait! For the people with MHO, their risk was about equal to the lean people if they remained health stable or improved their metabolic health.
Although, some cardiovascular outcomes might still be worse for MHO compared to the lean controls, even when the other metabolic markers are equal (see the new paper again on this).
How do people go from MHO to MUO?
The factors that increase the risk of having MUO include being older, having a high BMI to start with, having worse health outcomes to begin with (like fatty liver), smoking, poor diet, physical inactivity, and further weight gain.
But these factors aren’t understood in an actionable way yet. How are poor diet or physical inactivity defined? How long would someone need to have a “bad” lifestyle to transition to MUO? These are some questions I asked myself.
Does weight loss always help people’s metabolic health?
This is my favorite question. According to Dr. Samuel Klein who presented on this topic at the conference, it depends. He thinks that each individual has a level of weight gain that would cause them problems (like insulin resistance). And there is a different level of weight loss that might help different people with obesity. So, it depends.
Now I’ve demonstrated that obesity doesn’t equal “unhealthy” through discussing MHO. Someone’s health is made up of so many things that you can’t see, so the presence of visible fat isn’t a crisis in itself.
However, some people use the knowledge that obesity can be related to metabolic problems to justify their hatred and derision of people with obesity.
How many times have you heard “Being fat is a choice” or seen people get mad that plus-size models are on the cover of magazines?
A lot of these haters justify their rhetoric by saying they are actually trying to combat obesity since it’s so bad for your health. Today you’ve learned that obesity is more complicated because someone can still have metabolic health at a higher weight. Health isn’t something you can see with the naked eye, or on the scale.1
The next time you hear/see someone talking badly about people with obesity under the guise of caring for them, I hope you can give them an “Well…aaactuallyyyy” on my behalf.
That being said, even if someone is unhealthy (metabolically or otherwise), that is no reason to harass, discriminate, or stigmatize them.