Why are we getting fatter?

From PhysOrg:

Allison, a professor of biostatistics in the UAB School of Public Health, is senior author on a paper to be published Nov. 24, 2010, in the British journal Proceedings of the Royal Society B. That paper, provocatively titled “Canaries in the coal mine: A cross-species analysis of the plurality of obesity epidemics,” suggests that the root cause of obesity may be much more complicated than the conventional wisdom — too much food availability, too little opportunity to exercise.

Allison's current sleuthing began when he was looking over data on small primates called marmosets from the Wisconsin Non-Human Primate Center. He noted that the population as a whole showed pronounced weight gain over time. Checking with the center, he could find no compelling reason. The nature of the diet had changed, but controlling for the exact date of the change, easily doable with animals living in a controlled laboratory environment, only strengthened the mysterious phenomenon.

More here.