The figure varies by study, but it's safe to say that about 25% of us in the US are obese (vs. those who are simply overweight, which accounts for another 30% of the population). With all those skin folds and mounds of blubber to negotiate, the tiny x-rays and radio waves don't stand a chance of detecting much of anything, except the outline of said mounds of blubber. I am reminded of an unsavoury incident during my residency many years involving a middle aged obese lady. As the code team arrived in the patients room, they were surprised to find the slightly gnawed on Ham sandwich she had placed under her left breast earlier that day. I'm sure the TSA couldn't have protected me from that ham sandwich were the lady to pass through a body scanner, so it would be interesting to see what other benign objects individuals might be able to pass through airport body scanners attached to their persons. I began thinking about this on Wednesday morning at the DFW E-8 checkpoint where the TSA had cordoned off the body scanner lane for some kind of exercise. I observed their exercise for about ten minutes before being unceremoniously asked to hop it. However, during the time I was comfortably seated, slowly tying my shoelaces, re-arranging bags, etc, I saw three particularly well insulated TSO's repeatedly go through the body scanner, supervised by a suited gentleman and his colleagues who were apparently directing the exercise. Of course, the body outline of the three TSO's participating in whatever it was I observed is likely unrelated to my curiosity on obesity and body scanners, but the question remains, if the body scanner were to become mandatory for all passengers, how effective would it be in regards to screening passengers of size?