Alternative causes of the obesity epidemic

Few doubt America is undergoing an obesity epidemic.

Very fat people dislike the stigma, but they're on the leading edge of a national trend.

Most figure the cause is a lack of proper diet and hard exercise. But other explanations deserve exploration, according to a paper put on the National Institutes of Health web site recently by 18 prominent researchers.

What are some of those explanations:

• Viral infections from the environment.
• Changes in how genes are being expressed.
• Later childbirth.
• Fat people having more kids than thin ones.
• Fat people mating with each other, i.e., not mating with thin people.
• Sleep deprivation.
• Environmental pollutants like BPA, a chemical Janet Fang discussed just the other day.
• Prescription medications.
• Air conditioning, which keeps us all at a comfortable temperature so we don't process food as fast.
• Changes in how we develop as infants.
• Over-eating by expectant mothers.

In all these cases there is some evidence, either observed or experimental. But a firm case has not been made on any of these causes. And even this list may not be exhaustive, the authors feel.

Their conclusion may be billboard material for your favorite fat friends:

In this unusually public discussion it is imperative that scientists remain open to alternative ideas, insist that claims about the causes of the obesity epidemic be grounded in the best available data, and recognize that any one explanatory theory must be viewed in the context of the constellation of plausible, interrelated, and in many cases still unproven hypotheses.

Obviously, each one of the authors can have a fulfilling career following even one of these paths.

But here's my problem. Let's assume that sitting in air conditioning, drinking from a plastic bottle,  prescription medications, and changes in how genes are expressed are all contributing to what we see on the street.

Why is obesity so much more prevalent in America (and northern Mexico) than the rest of the world? French people get prescriptions, Italians drink from plastic bottles, and the Chinese are often exposed to environmental toxins.

The cure remains the same. Eat less, exercise more. It may well be true we need to eat even less to maintain a healthy weight than our grandparents did. That conclusion seems downright reasonable.

But you don't have to be a restaurant pitchman to lose weight and even run a marathon at a steady 5 miles per hour.

The causes of obesity may be diverse, in other words, but the cure remains the same.

This post was originally published on Smartplanet.com