Thursday, July 28, 2011

What You See, Part 3

Part 3 (from this article):
But the researchers found that the kinds of foods people ate had a larger effect over all than changes in physical activity. “Both physical activity and diet are important to weight control, but if you are fairly active and ignore diet, you can still gain weight,” said Dr. Walter Willett, chairman of the nutrition department at the Harvard School of Public Health and a co-author of the study.  As Dr. Mozaffarian observed, “Physical activity in the United States is poor, but diet is even worse.”
Most good trainers will tell you that “you cannot out train a bad diet.”  In other words, exercise is great but it won’t save you from a bad diet, especially if you are already overweights.  So there’s nothing new here, and there’s really no way they could reach such a conclusion, even an obvious one, from this observational study.  They are either expressing an opinion they already held or gained from another source.
Even more important than its effect on looks and wardrobe, this gradual weight gain harms health. At least six prior studies have found that rising weight increases the risk in women of heart disease, diabetes, stroke and breast cancer, and the risk in men of heart disease, diabetes and colon cancer.
On this, there’s little argument.  There’s still an argument about whether it is the fat itself, or the food one ate to become fat, that causes the increases in mortality that are seen in obesity.  However, it’s even more complicated than “what causes what”.  There are healthy fat folk and sick fat folk.  It’s a matter of degree, as in really fat is still also always a condition with many symptoms of sickness.  But folks who gain 20 pounds and hold there can be relatively healthy.
The beauty of the new study is its ability to show, based on real-life experience, how small changes in eating, exercise and other habits can result in large changes in body weight over the years.
This is just not true, because an observational study can show no such thing.  All that is “shown” is “co-relations”.  The author is assuming she can determine causation, because several of the “co-relations” can be placed into her “fat people eat too much and work out too little” model of weight gain.   From where she's standing, that's all she can see. Part 4 tomorrow.  (Minor edits 28 Jul 11)

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