Exactly What Do “Modifiable” and “Preventable” Mean?
“Modifiable” and “preventable” are two words sprinkled freely in the scientific and policy literature on obesity. They can be subtly but profoundly misleading.
A study recently published in JAMA Surgery analyzed the relationship between 25 “potentially modifiable” post-operative behaviors of bariatric surgery patients and weight outcomes three years after surgery. They found three behaviors that, depending upon how they change after surgery, explain most of the variability in how much weight people lost.
People who started weighing themselves weekly, stopped continuing to eat when full, and stopped eating continuously during the day after surgery lost significantly more weight after surgery.
The obvious catch here is cause and effect. The authors say it succinctly:
This was an observational cohort study, and the data cannot be interpreted to demonstrate a causal relationship between weight loss and eating and weight behaviors. The direction of influence cannot be ascertained.
Not weighing may result from feeling bad about not losing weight, rather than the cause. Eating continuously through the day may result from not getting relief from hunger that the surgery should have produced. Eating when full may result from drives to eat other than hunger that the surgery did not alter.
That’s why this study serves only to generate ideas for new research, not as a roadmap for ways to improve success. It’s all to tempting to say, just adopt these behaviors and you’ll be more successful.
The notion that behaviors like these are modifiable is a trap. Yes, they are potentially modifiable – and especially for the short term. So, too, is one’s weight modifiable in the short term. But the long term is an entirely different matter for many people with obesity. Biological forces get the way and nudge both weight and behaviors back into a familiar groove.
In the same way, obesity is potentially preventable. But decades of effort to prevent it are running into the harsh reality that simplistic prevention strategies are not working. Slogans like “let’s move!” and “eat healthy!” have broad appeal, but have not been enough to move the needle. The prevalence of obesity in both children and adults continues to rise.
To earn the right to say that risk factors are indeed modifiable, we need options that really work well for most people. Before we can say that obesity is truly preventable, we need to show some real success in preventing it.
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April 30, 2016