Last week's column dealt with what I described as the risks of "collective codependency," as reflected on both coasts: in the formation of a drug user's union in San Francisco and in Mayor Michael Bloomberg's efforts to ban super-sized surgery drinks in New York City.

Several days later The New York Times featured an op-ed piece by Dr. Daniel Lieberman, who teaches evolutionary biology at Harvard. Lieberman argues that Bloomberg is right to coerce New Yorkers to behave in particular ways. In fact, he concludes, "We have evolved to need coercion."

Briefly, Lieberman's reasoning is as follows:

1. We once needed massive amounts of fat because we were a race of hunter-gatherers.
2. Our bodies evolved to convert other foods into fat and they were particularly good at converting sugar.
3. But our ancestors were much more active than we are. Their activity was tied to their immediate need for survival. And sugar was in short supply. So, this "exquisite" ability to convert other foods into fat had no major downside.
4. Now, however, sugar is available in massive quantities. We no longer engage in the same level of physical activity, but we still crave sugar that we can convert into fat.
5. Sadly, we have not evolved to crave going to the gym instead of chasing down mastodons, so we are fat (collectively speaking).
6. To make matters worse, education has not changed our behavior and science has not discovered a way to end-run the damage done by our eating habits.
7. So we need to be forced to behave.

I have re-read Professor Lieberman's article a number of times almost certain that I've somehow misrepresented him, but I think that this is an accurate summary of his argument.

Brief as it is, his article suggests any number of interesting topics for conversation around the dinner table or in the classroom:

1. The unfortunate and uneven character of evolution that could stick us with a system designed for dear old great, great, great, great, great granddad and grandmom, ignoring all the other progress we've made technologically.
2. Evolution's failure to adjust for other kinds of change on a regional or even national basis. Obviously the ability to convert sugar to fat still works really well in some parts of the world—can't we have a North American adaptation?
3. The rather late breaking realization that where evolution is moving us and where it is still defective is a judgment made in Cambridge, Massachusetts.

Questions abound as well:

1. Are Americans the product of old evolutionary progress, trapped in a technologically advanced society?
2. Are the technological advancements of western society an anomaly that is deeply at odds with evolution's goals for us, or the product of another, competing evolutionary map?
3. Is the evolution of our bodies behind our brains, or is the evolution of our brains behind the evolution of our bodies—figuratively speaking?
4. Or is the problem that evolution simply hasn't found a way to eliminate the 32-ounce cup yet?

Okay, I'm being flippant. But really, "We have evolved to need coercion?"