The biggest cause of premature death today isn't in the air or water -- it's on the dinner table. 

A landmark new study published in The Lancet, a medical journal, examined 79 different health risk factors across 188 countries. Researchers found that poor diet is responsible for one in five deaths worldwide -- more than any other factor.

In other words, what we're collectively eating is deadlier than smoking, alcohol, and air pollution.

The good news is that these diet-fueled deaths are eminently preventable. The remedy simply requires paying more attention to what we put in our bodies -- and recognizing that the food choices we make have as much influence over our health as the air we breathe or the medicines we count on to fight disease. 

A landmark new study published in The Lancet, a medical journal, examined 79 different health risk factors across 188 countries. Researchers found that poor diet is responsible for one in five deaths worldwide -- more than any other factor.

The study, conducted by scientists from the Institute for Health Metrics and Evaluation at the University of Washington, found that 14 dietary risk factors contribute to the most deaths worldwide. The risk factors are unsurprising: diets low in things like fruits and vegetables and high in processed foods, added salt and sugar, and red meat. 

The poor global diet is producing a generation of unhealthy individuals. People who don't eat the right mix of foods fail to get the nutrients they need to preserve their health. That lack of proper nutrition leads to dangerous physical conditions that leave people vulnerable to deadly chronic diseases.

Take obesity -- a common product of a poor diet. Americans today consume 23 percent more calories than they did 40 years ago. It shouldn't be surprising, then, that more than one in three American adults is obese -- and two in three are overweight.

There are now over 2 billion overweight adults worldwide. That's nearly one-third of the globe's population. Some 600 million people are obese.

Obesity puts people at increased risk of developing chronic diseases like diabetes -- the risk factor associated with the fourth-most deaths globally. Between 1990 and 2013, diabetes rates shot up in 185 countries worldwide. They decreased or stayed level in just five.

Today, one in twelve adults suffers from the Type-2 variant of the disease.

Areas once defined by lack of food are instead suffering the devastating effects of widespread poor nutrition. In India, for instance, high blood pressure and high blood sugar contribute to over 3 million premature deaths annually. In Latin America and the Middle East, obesity is now the top cause of poor health.

Fortunately, fighting the epidemic of poor eating -- and thus, poor nutrition -- is entirely within our control. 

It starts by doing what our parents told us to do -- eating a balanced diet with plenty of fruits and vegetables. But there's a modern-day addendum to this sage advice -- we also need to get enough protein. 

Protein is especially important for the largest growing population: the baby boomers. Older adults need about twice the amount of protein typically recommended by dietary guidelines, according to research published this year in the American Journal of Clinical Nutrition. 

Unfortunately, they're not even getting the recommended amount. One in two older adults today is at risk of under-nutrition or malnutrition.

Proper nutrition is also of higher importance for people battling chronic disease. No amount of medication can fight disease as intended if the body in which it's operating is malnourished. 

In fact, nutrition is effectively a form of medicine itself. Eating right can pre-emptively ward off chronic disease -- or compensate for previous damage that may have led to its onset.

What people are eating -- or not eating -- has emerged as the biggest threat to global well-being. We can extinguish that threat by simply improving what we put on our plates.

Robert H. Miller is Divisional Vice President, Research & Development, Scientific and Medical Affairs at Abbott.