According to every diet infomercial out there, fitting into your skinny jeans is the ultimate health goal. But the true markers of health go beyond looks.
Consider two terms being thrown around lately: “skinny fat” and “fat and fit.” Someone with a tiny waist may actually face more health issues than an athlete whose body mass index (BMI) qualifies as obese.
Confusing, right? So let’s dive into each of these terms, the risks associated with the two types and whether either one can really and truly be healthy.
What Is “Skinny Fat?”
You probably know the type: the person who eats French fries, never passes up dessert and opts for “Friends” marathons over the gym, yet still magically fits into the same jeans they wore in high school.
But maybe you shouldn’t be so envious. There could be a host of health issues lurking beneath that skinny surface. “We tend to call it metabolically obese normal weight,” says Eduardo L. Grunvald, M.D., a board-certified internist with UC San Diego Health System and director of the UC San Diego Weight Management Program.
A “skinny fat” person has a normal body weight and BMI, but battles the same health issues as someone who qualifies as obese, such as diabetes, elevated cholesterol, high blood pressure and metabolic syndrome, Grunvald says.
The Problem With “Skinny Fat”
It all comes down to how the body stores fat. “Skinny fat” people have inefficient fat cells, so rather than being distributed evenly throughout the body, fat tends to accumulate in the belly, in and around organs and muscles, Grunvald says. “That’s dangerous fat,” he says.
“That fat causes insulin resistance, which is the central problem that leads to the other issues like diabetes, fatty liver and heart disease.” Insulin resistance occurs when the body doesn’t absorb glucose as it should, so the body tries to make up for it by putting glucose production into overdrive, which ultimately leads to various health issues, according to the National Institutes of Health.
A 2013 study published in PLoS One found normal-weight obesity, which describes people with a normal BMI and body weight but a high body fat percentage, went hand in hand with metabolic syndrome and insulin resistance.
“Just because you’re thin doesn’t mean you can’t have high blood pressure and diabetes and all of those things,” says Kathryn A. Boling, M.D., a primary care provider with Lutherville Personal Physicians.
Are You “Skinny Fat”?
It’s nearly impossible to look at someone and tell right off the bat if they qualify as “skinny fat,” though a disproportionate waist circumference is usually the biggest tip-off, Grunvald says. To explore whether there’s a problem internally, a doctor will likely ask about your lifestyle habits and family history and may recommend a series of blood tests.
If a problem exists, your doctor will likely recommend lifestyle changes to fight insulin resistance. “Exercise — even if you don’t lose weight — is very good for improving how the tissues respond to insulin,” Grunvald says.
Diet also plays a role. “The typical Western diet is very processed — lots of refined sugars and carbohydrates, which tend to elevate our insulin levels, which in turn causes fat deposition and insulin resistance,” Grunvald says. Sticking to a Mediterranean diet can reverse the issues associated with obesity, finds a 2014 study published in the journal CMAJ.
What Is “Fat and Fit?”
“Fat and fit” is essentially the opposite of “skinny fat.” These are the people who knock out a five-mile run every morning, despite looking a little stocky. They live a healthy lifestyle but don’t sport six-pack abs and toned shoulders — or any of the health issues that many overweight people battle, such as high blood pressure and diabetes, Boling says.
“Some people can have a lot of fat tissue and be metabolically healthy,” Grunvald says. “You don’t have to have a good BMI in order to have good cardiovascular fitness.”
The “Fat and Fit” Advantage
As it turns out, these “fat and fit” types are healthier than “skinny fat” people, Grunvald says. And they may even live longer than their slimmer peers. A 2012 study published in the journal PLoS Medicine reviewed data from more than 650,000 people. The researchers found those who had normal weight but were inactive lived an average of 3.1 years less than those who were obese and active.
Here’s why: The fat in “fat and fit” people doesn’t tend to accumulate in the dangerous midsection. “You can have an increased body fat percentage, but if it’s distributed like the kind of fat that doesn’t cause metabolic problems, then you may not have any of those issues — the insulin resistance, the diabetes, the cholesterol problems,” Grunvald says.
The Threat of Weight Gain
Both Boling and Grunvald agree that unless a “fat and fit” patient is unhappy with his body, there’s no need to put him on a restrictive weight-loss plan. “If you needed to choose between weight loss and being cardiovascularly fit, I would choose the latter,” Grunvald says. “That’s probably better for your overall long-term health than only focusing on your weight.”
However, “fat and fit” types should regularly step on the scale to ensure their weight doesn’t creep up. “As your BMI goes up, you start developing fat mass problems,” Grunvald says. “You start getting the joint problems, the sleep apnea, the acid reflux — those kinds of issues that are directly related to mass.”
You’ll also increase your risk of developing issues traditionally associated with obesity. A 2015 study published in the Journal of the American College of Cardiology questioned whether “fat and fit” adults could maintain their healthy profile over time.
The researchers tracked people for two decades. Of the 66 participants who qualified as healthy and obese at the start, 31.8 percent were unhealthy five years later, and more than 50 percent had moved to unhealthy territory after 20 years, indicating that most “fit and fat” people eventually slide into being overweight and unhealthy as time goes on.
Weight stability among “fat and fit” patients is key. “You want to prevent further weight gain, and you want to prevent further problems,” Grunvald says.