01/06/2011 05:03 pm ET | Updated May 25, 2011

Worried About Your Weight? How Much Can You Control?

How do we know what is really in our control? Many of us do a number of things to prevent illness; we exercise, eat fruits and vegetables, don't smoke, try not to drink too much, etc. But the reality is, some people do everything right and still get sick.

It may also be that some people who engage in the right behaviors to manage their weight are still heavier than they want to be. A new study, reported by Stephanie Pappas, suggests that obesity is increasing in animals, though it is unclear why. Although too many calories, combined with lack of exercise, is still thought to explain why humans carry around extra weight, David Allison and his colleagues found that a number of animals, from monkeys to mice to dogs, are fatter. For example, male mice increased their weight by over 10 percent in a decade and male macaques by over 7 percent in a decade.

If diet was simply the explanation, then we could understand how domestic animals, such as dogs and cats are bigger -- they live with us and perhaps are eating more food. Even rats, which were also found to be increasing in size, could be ravaging our leftovers. But as the article states, many of the animals in the study are in laboratories, where their diets are controlled.

Allison explains that the reasons for these findings are unknown. Many factors unrelated to eating and exercise are thought to contribute to weight gain, including sleep deprivation, excessive light at night, and a virus. Also, there are a number of substances in our environment, particularly those in plastic and other common products that are thought to make us more susceptible to packing on the pounds.

So while it is important to think about topics such as food addiction, the ways people comfort themselves with food when anxious, why people won't exercise, and all of the other psychological factors we associate with weight gain, it seems important to take a step back and realize that maybe even weight is something that is hard to control. What would it mean if we were to really stop blaming people who are overweight? What if we were to acknowledge that like many illnesses, one may do many of the right things and still be obese? Although I could say that fat prejudice is still one of the few acceptable biases, I am not sure this is solely why people are unsympathetic to overweight people. I don't think it is just about appearance. People get anxious about admitting there might be factors that can't be controlled in obesity, in the same way that many of us are frightened about uncontrollable facets of illness. It's hard to think there are aspects of our bodies and our health that we simply can't influence as much as we want to.

The illness of obesity is an easy target for our derision. It just may not be fair, given emerging data.