Tuesday, May 06, 2008

Can you be fat and fit? Latest spin says "No"

Based on a "data dredge" study (meaning they took existent data which was not designed for THAT study so is outdated and also doesn't usually have the right information), some of those in the diet industry are now telling us that we cannot be fat and fit.

The study, like other epidemiological studies boasted big numbers, 39,000 women classified as normal weight, overweight or obese (BMI 30 or over). It was published in the Archives of Internal Medicine, April 28, 2008 issue.

I looked up the article, because the news service headlines read "Fitness does not reduce risk if you are fat". The media told us that people who were obese had a 50 percent greater rate of heart attack even if they exercised than people who were not obese.

If the study had really suggested this, it would be very questionable ... the exercise habits were self reported and people often exaggerated their level of fitness (mostly exaggerate it!). Also overweight and obese women are often weight cycling (popularly called "yo yo dieting") because the body produces all kinds of hormones to force weight gain if it thinks your weight is too low (and too low varies for every different body). And of course, several CLINICAL studies have suggested that any kind of dieting increases heart disease risk by 50 percent.

However, in looking up the abstract, the study did NOT suggest that there was no benefit for an obese person to be fit. On the contrary, the last line of the abstract reads:

The risk of CHD associated with elevated body mass index is considerably reduced by increased physical activity levels.
The media ignored this statement and picked up the next line in the conclusion:

However, the risk is not completely eliminated, reinforcing the importance of being lean and physically active.

Ok, that's fine except it is a meaningless statement because a reduction in risk doesn't mean no risk... regardless of weight. However, it made a great statement for the media to base yet another article of misinformation on.

Now if we look at the study further, we find that although researchers wanted the expenditure of 1000 calories in exercise a week (which isn't very much... about 3 x a week, 40-60 minutes each time), the average expenditure in calories in exercise for those considered "active" (remember this is self reported) was 550 calories a week which isn't for most people, even twice a week. And even that small amount, said the researchers, reduced the risk of CHD significantly regardless of weight (34 percent, they stated).

It should be remembered that many people feel NON cardio is exercise to be counted like gardening and likely reported that as "activity" even if it didn't fit in the categories which were basically cardio exercise (I guess gardening could be reported in the "walking" category if you stretched it).

So although this wasn't the best designed study (to put it mildly) the results were not what the news media reported them to be. Exercise does significantly reduce the heart disease risk... regardless of weight.

Rudy Leibel, obesity researcher said "there probably is a benefit to being of 'normal weight' but there is no proof that people forcing their weight down below their set point enjoy that advantage". This is kind of a no brainer and I have no problems with it. Although right now, according to CDC statistics, people in the BMI category of 25-35 are living longer than those in the so called "normal weight" category.

Another strange thing in our society is that although most of us have had friends who exercise a lot of cardio, are lean but smoke cigarettes, drop dead rather early in life, I have not noticed any studies suggesting what we already know to be true - that smoking may cancel out the good effects of exercise in some individuals (regardless of weight or fitness level).

And in fact, many people who smoke, are doing so to keep their weight down because they are under the false conclusion that doing anything unhealthy is better than being fat. And of course, where do they learn that but from our media.

The Cooper Institute studies of 50,000 people over the last 30 years or so, suggested that people who were obese and fit had only a 00.08 greater risk of heart disease than those who were normal weight and fit. And those studies also suggested that being lean (under normal weight) was at the highest risk even if fit. But of course you will never see that in the media which is, bottom line, hard selling a diet.

One more comment about this study. Most people do not keep up a fitness program more than a year or two but in a self reported study, those people may not have reflected the change (stopping exercising) in their surveys.

Exercise greatly cuts risk of illness regardless of what people weigh but cutting risks doesn't mean no risk, of course. And to enjoy that reduction of risk, people must make cardio at least 3 times a week (and 5 times a week is way better) a part of their lives FOR life.

And it seems the greatest risk to our health may be believing the media which when not lying, is incorrectly reporting health topics.


Jennifer said...

Most people do not keep up a fitness program more than a year or two but in a self reported study, those people may not have reflected the change (stopping exercising) in their surveys.

This is one of my biggest problems with this kind of survey-based study. Of course many people are going to overestimate how much they exercise. And I have no proof of this, but I bet that fat people (who are conditioned to view themselves as lazy and bad) are going to think "of course I don't exercise enough--I'm still fat," whereas thin people are probably going to feel like they get adequate exercise just by virtue of being thin, and report accordingly. Even with all my suspicions about this kind of thing, the study does seem to show that moderate activity leads to reduction in heart disease risk regardless of weight. So that's a good thing.

SueW said...

Erin writes:

Sue -

Absolutely GREAT comments. It is wonderful to see the research you are doing to contradict the media's spin on obesity! I have been doing more and more digging at the local medical library and I am STUNNED at how much mis-information is out there on obesity and the "war on obesity".

Thanks for doing some great work! I am going to keep coming back for more!


Thanks for the kind words!

Equality on the plains... said...

I came back to hear the voice version of this. It was actually fun to hear! ^_^

I don't act to be a researcher or anything, but I picked up some of the things you said as well. As the person from the other study said: This wasn't an objective look into this, so it shouldn't be used as such.

One point that Sandy (JFS) brought up was this study also acknowledged that anything beyond an 1.5 hours a day (I believe that was the number) in exercise is actually counterproductive, and if we were to support the data, making a person of ANY size workout more than that actually INCREASES heart attack risk.

And they still haven't mentioned the studies showing that overweight and obese people have lower MORTALITY rates for heart attacks as well. That's a big no-no. lol

Thanks for helping yet again.