Human Limits

Exploring performance and health with Michael J. Joyner, M.D.

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Fit vs Fat?

I got an e-mail a couple of days ago from a friend and reader who is world-class engineer/leader for a large company who just returned to the US after several years on an overseas assignment.   Here is an extract from the message:


“I read the blogs for the past month, very interesting.  There was a lot of coverage of obesity…….something I know firsthand, all too well, unfortunately.  You’d think I’d listen to such good advice and make some changes.  But, as you say, it is a complex issue.  I hope that just one poor risk factor out of six, will not be too bad.”


This got me thinking about the whole obesity issue and perhaps it is time to stress some good news.  That having been said, there is pretty convincing evidence that remaining fit and active can trump a lot of the negative health risks associated with obesity.   The graph below shows the relative risk (RR) for all-cause mortality (top panel) and cardiovascular disease (CVD) mortality (bottom panel) in lean, normal and obese subjects.  The dark bars are for unfit people and open bars for fit people.  The study comes from the Cooper Center database and included almost 22,000 men.   The numbers of above the bars are numbers of deaths in each group over a multi-year period of observation.



The dark bars show that obesity puts people at increased risk for both all-cause mortality and cardiovascular disease.   This increased risk is clearly amplified by being unfit.   By contrast, all-cause mortality was lower in the fit people and the amplifying effects of excess body weight were much less.  There are all sorts of reasons why being fit and active can trump other risk factors like obesity; less diabetes, blood vessels that can stay relaxed, and better blood pressure control to name a few.   The other issue here is that people need to avoid getting hung up on losing a set amount of weight to reach an “ideal”.    Losing just 5 or 10 pounds can really make a difference in a number of risk factors and is especially effective if it is accompanied by more physical activity.

So here is an encouraging thought from a recent study for people who worry about their weight:


“Higher fitness should be considered a characteristic of metabolically healthy but obese phenotype. (ii) Once fitness is accounted for, the metabolically healthy but obese phenotype is a benign condition, with a better prognosis for mortality and morbidity than metabolically abnormal obese individuals.”


Or as Dr. Chip Lavie, a noted cardiologist and fitness expert from New Orleans, said recently in the New York Times:


“Maintaining fitness is good and maintaining low weight is good, but if you had to go off one, it looks like it’s more important to maintain your fitness than your leanness……”


So don’t get discouraged, do stay active, and don’t get too hung up on your weight if you are staying active.


One Response to “Fit vs Fat?”

  1. October 17th, 2012 at 7:57 pm

    Fit vs. fat: Pay more heed to the former than the latter « in the deed says:

    […] You can read all of Joyner’s blog entry here. […]

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