The Journal of the American Medical Association recently published a study purporting to link increased soda consumption with weight gain.
This comes on the heels of studies linking obesity to urban sprawl, longer commutes to work, time in front of the television, time on the Internet, not enough physical education in schools, vending machines in schools, marketing and advertising of junk food to children and countless other trends, foods, habits and (in)activities.
Unfortunately, a slew of nutrition activists and nanny-statists want to use the fact some Americans are getting bigger to limit what all Americans can choose to eat.
So we're seeing lawsuits waged against food companies, calls for "fat taxes" on calorie-dense eatables and moves for restrictions on the advertising and marketing of junk food.
Sensible people oppose such measures and prefer a system where everyone is free to make his or her own decisions about diet and lifestyle, but also is required to bear the consequences of those decisions.
There are a number of things we can do that could both facilitate an increased sense of personal responsibility and harness the power of the marketplace to encourage good decisions about diet and activity.
For one thing, we could allow health insurance companies to do "medical underwriting" - charging lower insurance premiums for people who exercise regularly and follow healthy diets.
That only makes sense, as those people are expected to have lower health care costs than doughnut-munching couch potatoes.
Standing in the way of medical underwriting are legal prohibitions against allowing insurers to assign risk in health insurance premiums the same way they do with auto and life insurance premiums.
Many states require insurers to charge the same premiums for any member of a group health plan, regardless of risk. Removing those barriers would encourage insurers to begin experimenting with carrot-and-stick approaches to healthy lifestyles.
Bringing the costs of unhealthy lifestyles closer to consumers encourages more careful attention to lifestyle choices.
A nationwide market for health insurance would go a long way toward restricting the obesity problem to the obese, instead of subsidizing it by spreading the costs of weight gain over the entire population.
Michael Cannon is Director of Health Policy studies and Radley Balko is a policy analyst with the Cato Institute.