I think Steve hit most of the points I would have made health wise, but I would like to add increased risk for medical complications. An overweight person is much more difficult to perform a physical exam on, lumps, bumps and, nodules can be easily missed. Routine medical procedures like IV placement and spinal taps are way more difficult, in certain circumstances this can delay emergency and even life saving treatment. Then when things go really wrong; trying to intubate heavy patients, let alone perform effective cpr, can all be incredibly challenging. I have run out of needle trying to get into a patients spinal canal. Now this last comment is not designed to poke fun, but to point out that humans are moving to the limits of our current equipment, from the spinal needles being too short, to people being too heavy for ct scanners or MRi tables. The idea that there is gain associated with being out of shape is just a ridiculous statistical one liner.