BMI, which stands for body mass index, is determined based on a person's height and weight. You're considered overweight if your BMI is between 25 to 29.9 and you're obese if your BMI is 30 or above.
Chances are, even if you are not "fat," by definition of these traditional measurements, you may still be "overfat." And that's going to have some seriously negative consequences for your overall health.
A new study published in the journal Frontiers in Public Health suggests the number of people who meet the criteria for overfat in the top 30 industrialized countries are more than all of the obese and overweight people in the world. In fact, they estimate that 90% of the men and 50% of the children in the US, New Zealand, Greece and Iceland are overfat. In the top overfat countries, researchers found 80% of the women were overfat, too.
This adds to previous research published in January that first suggested "the term more accurately encapsulates the problem itself."
And if doctors rely only on the definitions we use to consider someone "obese," or "overweight," they may not be helping all the patients they should.
What is overfat?
Overfat is a term created to describe if you have a body fat level that can actually hurt your health. Even people who are considered "normal weight" or "non-obese" by traditional standards can fall into this category.
The authors of this new study argue that BMI misses about 50% of the people who still have dangerous amounts of fat. Those are typically people who have the proverbial beer belly, but are otherwise in decent shape.
"We shouldn't be as much worried about weight," said author Paul Laursen, an adjunct professor and performance physiologist at the Sports Performance Research Institute in New Zealand. Your scale or that BMI calculator don't know that you could be an athlete and have a lot of muscle mass, or a growing teen. Or, you could have gone on a fad diet and lost 3 pounds, but that doesn't necessarily make you healthier -- that 3 pounds could merely have been water weight, he said. "What we should really be worried about is the fat part and where your fat is concentrated."
Why's belly fat so bad
Abdominal fat is one of the most dangerous kinds of fat you can have. The reason it's so bad is that unlike your love handles -- which are the pinchable fat right beneath your skin -- the fat that is in your stomach area grows deep inside your body and it wraps around your vital organs. Your liver borrows this fat and turns it into cholesterol that can sneak into your arteries and start collecting there. When it collects, your arteries start to harden, and when they get hard, this can lead you to having a heart attack or stroke.
This deep layer of belly fat is also what makes your body insulin-resistant, which can lead you to having type 2 diabetes. It can also cause inflammation, which scientists are finding at the root of many chronic diseases and even cancer and Alzheimer's. Excess belly fat can also raise your glucose levels and decrease your muscle mass. You need good muscle mass to help keep good heart health.
It's no wonder earlier studies have shown that excess belly fat, even if you are skinny elsewhere, may be even more deadly than being obese or overweight. And that's saying a lot, since good old fashioned obesity is related to all sorts of diseases and potentially life threatening problems like cancer, heart attacks, stroke, asthma, sleep apnea, high blood pressure and a handful of other problems.
If a doctor is relying on BMI to assess your potential danger from your fat, they miss the risk. Earlier studies have also shown that doctors that rely solely on BMI may miss other warning signs for people of different ethnicities put them at greater risk for heart problems and other health issues.
A better measure
What may be a better way to assess if you are overfat is for your doctor to look more like a tailor and take a tape measure to your waist, the authors argue. If you want to try this at home, measure your circumference at your belly button. If your waist circumference is half your height or less, you are at a healthy fat level. If you are over that number, your fat could put you at risk for ill health.
It's not as perfect a measure as if your doctor were to calculate your fat using an X-ray, but it's a good indicator, suggests Dr. Francisco Lopez-Jimenez, a cardiologist and obesity expert at the Mayo Clinic in Minnesota.
Lopez-Jimenez, who is not connected to this study, finds overfat an interesting concept and thinks the author's suggestion of measuring waist circumference is a good one. He said you could even do something simpler and look at your hip to waist ratio -- something a doctor could eyeball quickly. "If the waist is bigger than the hips, it tells me that the risk carried with that weight is much higher for that person for premature death," Lopez-Jimenez said.
But he's not convinced we need the term "overfat," as he thinks it over-complicates matters.
"It basically adds a little more complexity to an already complicated subject," he said. He suggests scientists may want to broaden the term "obesity" to include people with normal weight BMIs that carry too much fat around the middle.
Laursen thinks adding "overfat" to the lexicon will give doctors one more important tool.
"We are so conditioned to walking up to the doctor's office to get a pill for every issue, but that is not working. When it comes to excess fat, the onus is really on the individual to figure out what works for themselves," said Laursen, who added he gets upset that the overfat epidemic has become such a large problem for so many. By giving doctors another term it helps them have an honest conversation with their patients.
"Dealing with excess fat needs to be a priority," he said, "as it truly can put someone's life in jeopardy."