It’s Good To Be Fat?

Don’t you believe it!

News reports are citing a study that shows overweight (but not obese) people live longer than people who are of normal weight, as measured by BMI. We need to be careful here – note that the researchers use the term “modestly overweight”; we are not talking about obesity. Researchers also don’t know why this is the case. One theory is that the bodies of overweight but not obese people have more nutrional reserves and/or lean body mass than those of normal weight.

This raises an interesting question in my mind. What was the body composition of the “overweight” people in this study?

You see BMI, or Body Mass Index gives no indication of the body fat percentage of the subject. It is a math equation that uses your height and weight (you can read more about it and calculate your BMI here) to calculate a number, which is then plugged in on the BMI category chart to determine if you are overweight.

The BMI Is Bogus!

Here are the limitations of the BMI, as posted on the National Institute of Health website:

- It may overestimate body fat in athletes and others who have a muscular build.
- It may underestimate body fat in older persons and others who have lost muscle mass.

In other words, if you are in good shape BMI can indicate you are overweight, and if you are skinny-fat, it can indicate you are right where you are supposed to be. Not helpful at all, and hardly a scientific way to analyze data.

Let me give you an example.

Person 1 weighs 200 pounds with 10% bodyfat. This means he has 180 pounds of lean mass and 20 pounds of bodyfat. Most of us would be very happy with this. This person is in very good shape.

Person 2 weighs 200 pounds with 22% bodyfat (average American male according to Covert Bailey, and higher than NIH data – Who do you trust?). This person will have 156 pounds of lean mass and 44 pounds of bodyfat. Using the BMI, there is no difference between this person and person 1.

However it is a near certainty that person 1 will look better, feel better, have better blood lipid profiles, and a better quality of life.

Now it may be that the people defined as overweight in the study all had the profile of person 2, I don’t know.

What I do know is that most of the articles on the subject I have read don’t tell the whole story, and that quality of life needs to be looked at as well.

Who cares if you live longer (remember this study looked at mortality rates) if you can’t get out of bed or brush your teeth?

Bottom line is this – Eat a healthy diet, get regular exercise, don’t smoke, drink clean water.

And don’t let some study throw you off track.

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