‘Fat but Fit’ Is a Myth but Also It Isn’t

Health is complicated, and any exercise is still better than none

Look out, citizens: A new study claims the whole fat-but-fit concept — the idea that an obese person with the correct metabolic markers for blood pressure or blood sugar is still healthy — is about as real as Bigfoot. University of Birmingham researchers looked at the medical records of 3.5 million people in the United Kingdom, and found that those who were obese at the start of the study (defined as having a body mass index over 30) and had no signs of heart disease or high cholesterol still had double the risk of heart disease of those were not obese, The Telegraph reported.

But before we hang up our running shoes for good, let’s try to parse what’s going on here. For starters, the study isn’t published yet—it was just discussed at the European Congress on Obesity.

Second, this idea is not new, and medicine people and science people and fitness people and regular people have been debating this very issue for ages — if you’re fat but you can run a marathon, are you fit? If you’re thin but you can’t get up a flight of stairs, are you healthy? What if you’re fat but you don’t smoke? What if you’re thin but you do? Weight is not the only indicator of health, but the debate about the degree to which it hampers fitness is still unclear.

A 2012 study found, for instance, that obese people who are metabolically fit do not have a greater risk of heart disease or cancer than people who are in the normal weight range. But a 2015 study found that they did have a greater risk. If this sounds confusing for lay people trying to figure out just how much they are willing to move around every day to stave off death, it’s because it is. Another study found that even for people who are obese, exercise still prolongs life and offer health benefits — even if you do half as much exercise as you’re supposed to.

But back to the new headline: The idea here is that solid metabolic health — blood pressure levels or blood sugar levels within certain parameters — won’t put you in the clear for later risk if you’re also overweight. A doctor at the British Heart Foundation, Mike Knapton, told the BBC:

Previously we used to think that being overweight led to an increase in heart attacks and stroke because it raised your blood pressure or cholesterol. What was new from this study for me is that it showed that people who were overweight or obese were at increased risk of heart disease even though they may have been healthy in every other respect. Just being overweight puts you at increased risk of heart attack and stroke.

In response to the study, personal trainer Louise Green argued in The Guardian that this is nonsense and that you absolutely can be fat and fit, because she’s seen it personally:

Over the course of 10 years and thousands of training sessions working specifically with obese clients, I can say this: I have witnessed incredible feats in fitness by obese clients. I have trained both healthy obese clients with sound athletic disposition and immobile clients who couldn’t stand on two feet who were not metabolically healthy. Over time, I had them running up hills, boxing, lifting weights and making fitness a sustainable part of their life. During this time, their risks of disease greatly decreased without significant weight loss. Medications were lowered, cardiovascular health, physical mobility and quality of life were greatly improved.

And Dr. Ellie Cannon, a general practitioner for the NHS in London, wrote in Net Doctor that she finds the research troubling because it relies still on BMI, long considered an outdated measure—she prefers to use waist measurements. Cannon writes:

You can be fit because you exercise and are slim, which is then slightly ruined because you drink a lot, which may be slightly improved because you have a lot of omega 3 oils, which then may be reduced by a bad family history, and on and on.
Fitness has so many factors playing into, you are not simply fit or not. It is really impossible to define. Is a slim person who does no exercise fitter than an overweight person who does? No one can say because real life studies can never be done taking in all the real-life factors that make up all of our risks of disease. Some people will not be able to lose weight despite a good dose of exercise and healthy food. Exercise is definitively so good for people and such a protective factor, there is no way such people can be labelled “unfit” by this unilateral measurement.

Moreover, she writes, preventing heart disease is not the only measure of health — cancer, osteoporosis and mental illness can be just as fatal. And calling obese people “categorically unfit” is only going to discourage them. “Labelling fat people as categorically unfit is so unhelpful: we want to encourage all people to exercise, keep exercising and avoiding other risks,” she said. “We don’t want people who are overweight to think ‘Well, there’s just no point in trying.’ We should all be trying to include exercise in our lives, whatever our weight.”

So maybe, then, we should be putting this a different way: None of us knows how we’re going out; regardless, moving is better than not moving.

Tom Holland, an exercise physiologist and certified nutritionist, and author of numerous books on exercise and nutrition, tells MEL that the other big issue with how such research is framed is that these conversations do nothing to help the average person get their head around how to measure our own health or set fitness goals, which is the whole point.

“This debate has been going on forever,” Holland said by phone. “At the surface is what is the definition of ‘fit.’ Most people have no idea and would not even be able to answer that.”

Holland notes that researchers in these studies are looking at metabolic health, which is different from the physical fitness most of us think of — ability to get up and move around without getting winded immediately.

“Yes, there are a subset of overweight people who don’t have typical metabolic issues or complications from being overweight,” Holland explained. “That means bad cholesterol, high blood pressure, high blood sugar, inflammation, or higher levels of LDL cholesterol. The blood markers that lead to health issues. But the vast majority of overweight people have issues with at least one if not most of those. So that’s what doctors mean by fit — are they metabolically healthy — normal blood pressure, no cholesterol, no Type 2 diabetes. What this research is saying is you can be okay metabolically, but still have that high risk of coronary artery disease, heart issues or stroke risk.”

But even if that’s true, it doesn’t mean that losing weight is the most important reason to work out (which is good, since exercise isn’t that helpful for weight loss). Holland says he defines personal fitness by five markers — muscular strength, muscular endurance, cardiovascular strength, body composition and flexibility. “True fitness is these five things, and if you have these five things, metabolic health is going to fall in line.”

Instead of sweating these infinitely complicated broader risks, people should simply focus on improving their health. “Take the focus off the scale, but know every time you do something healthy, you’re doing something healthy,” Holland says. “Focus on what you gain — look better, feel better, live longer — and not what you lose.”

Tracy Moore is a staff writer at MEL. She last wrote about the fact that Chris Cornell was exactly the age for the highest suicide rate in men.

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