Before you read this, take a moment to Google “lifestyle and health.” If you do, you will be confronted by over a half-billion results. That figure is mind-boggling—but it’s not surprising when you consider how central the notion of “lifestyle” is to our conception of health. From diet books to fitness programs to government initiatives like the First Lady’s “Let’s Move!” campaign, our society is strongly invested in the belief that you can safeguard your wellbeing—if only you take personal responsibility for it.

WIRED Opinion About Dr. Sandro Galea (@sandrogalea) is a physician, epidemiologist, and dean of the Boston University School of Public Health

Recently, a study in Mayo Clinic Proceedings reported that, despite our collective fixation on health, less than 3 percent of Americans actually live a healthy lifestyle. How problematic are these findings? Certainly they are not ideal. The study defined a “healthy lifestyle” as the sum of four particular components: exercise, eating nutritious foods, maintaining a body fat percentage of under 20 percent for men and 30 percent for women, and being a nonsmoker. The vast majority of Americans fall short of those benchmarks, and that’s a problem. However, even if you meet all four, your achievement carries no guarantee of improved health. To truly better the health of populations, we must reevaluate our emphasis on lifestyle at the expense of other, often vital, considerations.

Over time, public health has increased its emphasis on the individual risk factors that can create poor health. In 2010, the United Nations referred to chronic conditions as “lifestyle diseases,” spotlighting smoking, physical inactivity, and a poor diet as factors that cause such illnesses. In the US, this kind of thinking goes back more than 50 years. In 1948, the Framingham Heart Study began to examine the role that a person’s behavior plays in causing heart disease. The centrality of lifestyle to our thinking about health began to coalesce in the 1960s, as research focus moved from infectious to chronic conditions.

Changes in how you live are no guarantee of changes in your health.

But today, public health researchers are beginning to see that changes in how you live are no guarantee of changes in your health. In 2001, a trial conducted by the National Institutes of Health followed more than 5,000 type 2 diabetic adults for eleven years. The goal of the study was to see if “an intensive lifestyle intervention” aimed at reducing body weight would diminish the chance of cardiovascular complications that can accompany type 2 diabetes. Over the course of the study, the participants did lose weight. But their rate of heart trouble didn't decrease.

This mismatch between lifestyle and health outcomes can also be seen in other areas. Say that you suffer from acid reflux disease. You may have heard that changes in your eating habits, the position in which you sleep, and your weight can bring relief. It would be nice if this was true, but a systematic review of the medical literature associated with the condition suggests that it is likely not.

The idea that lifestyle modification can lead to a better, more illness-free existence is a seductive one. It seems to offer a way of taking real ownership of your health. It implies that, with the right knowledge, you can predict which maladies you stand the greatest chance of facing. This makes prevention seem simple: If you can see the train coming, in order to preserve life and limb, you need only step off the tracks. This is not, however, how disease actually works.

It’s easier to accurately gauge the health of populations than it is to forecast the health of any one person.

Our capacity to predict the “odds” of a particular person getting a particular disease is extremely limited. The hazard of illness is the result of a host of factors—social, environmental, even economic and political. That is why it’s easier to accurately gauge the health of populations than it is to forecast the health of any one person.

For example, it is difficult—perhaps impossible—to predict whether you will develop asthma in your life. However, if you are, say, an African American child, and you live in the United States, you are about 6 percent more likely to suffer from it than your white peers. That probability has to do with the underlying structural drivers that have historically shaped the health of the black community in the US for centuries. Though predicting individual health remains problematic, when it comes to the wellbeing of populations, there are many afflictions we can see coming. In order to do something about these dangers, we must be willing to tackle the root causes of disease.

This means shifting our focus away from research that aims to simply cure disease, towards investing in the research that can protect the health of populations. Take, for instance, the work of Art beCAUSE, an organization dedicated to eliminating breast cancer. Their approach is to raise money for research that seeks to pinpoint the environmental factors that lead to the disease, so they can lower the incidence of cancer among populations.

By prioritizing lifestyle over the fundamental causes of disease, we risk ignoring the factors that are genuinely making people sick.

There are, of course, a number of lifestyle conditions that can increase your risk of getting cancer. They include being obese, smoking, drinking alcohol, and not wearing sunscreen. However, while individuals can reduce their personal risk of cancer if they are thin, do not smoke, do not drink, and always use sunscreen, living in a world full of carcinogenic smoke obviates any potential benefit from those lifestyle changes. As long as factors outside of the individual are part of the causal chain that produces health, unless we do something about these factors, no amount of lifestyle modification is going to prevent and lower the burden of disease in populations.

In 2009, author Dan Buettner gave a TED Talk entitled “How to Live to Be 100+.” It emphasized the search for “the optimal formula for longevity”—of achieving the kind of lifestyle that will dramatically increase your chances of living well and longer. This talk has since been viewed online over 2.5 million times. It's good that so many people are interested in self-improvement. The desire to get and stay healthy is admirable, and no one should ever be dissuaded from taking steps in the direction of greater wellness. But the fact that only about 3 percent of Americans seem to be doing so is not as discouraging as the fact that, by prioritizing lifestyle over the fundamental causes of disease, we risk ignoring the factors that are genuinely, and on a massive scale, making people sick.