Tuesday, July 26, 2011

What You See Depends Upon Where You Stand

Still Counting Calories?

This is an old quote I've often thought of considering how unusual it is for human beings to understand things in the same way.  I also think of the biblical story of the Tower of Babel - in which, it is understood that because of man's arrogance, which leads them to try and build a tower to heaven, God decides the only way to keep them humble is to ensure they do not understand one another and therefore, cannot ever really conspire with each other.

This is a polite way of saying - I see things a little differently than Jane Brody does.  However, as frustrating to me as that may be at times - since she has an audience and could do so much better for them - it is also a great opportunity for me to take a short ride on the Brody train to illustrate what I think are useful insights about diet, health and weight loss.

Here’s some of the ground we can cover:

What can you use an epidemiological/observational study for?
Why does calorie counting fail?
What happens when you use the wrong model to interpret data?
What is the role of expert opinion in science?
How can we be deceived by obvious falsities like the “heart healty whole grains” mantra?

On to Ms. Brody’s review of the study, from the link above (her comments italicized):

So the newest findings on what specific foods people should eat less often — and more importantly, more often — to keep from gaining pounds as they age should be of great interest to tens of millions of Americans.
It is inaccurate to call the results of an observational study (more on what the study design was in a moment) “findings.”  Rather, it is inaccurate to consider them to be “findings” as in “this study determined these causes and effects.”  Observational studies are useful in determining correlations, which can then be tested via intervention studies to determine what are causative agents in the correlations. 
The new research, by five and public health experts at Harvard University, is by far the most detailed long-term analysis of the factors that influence weight gain, involving 120,877 well-educated men and women who were healthy and not obese at the start of the study. In addition to diet, it has important things to say about exercise, sleep, and alcohol intake.
Of course, the experts must be cited, but let’s hope the experts, if asked, would agree that Ms. Brody is using the results of the study incorrectly.  An observational study has nothing “to say” about anything, beyond the fact that there is a “co relation” between some factors.  For example, the sun comes up and I get out of bed 99% of the time.  It may be the case that I get up because the sun comes up, or that the sun comes up because I’m about to get up.  We don’t know until we try some experiments to see which is true, if either, because both things could be caused by an additional variable.  Part 2 tomorrow.

No comments:

Post a Comment