Between the recent keto, gluten-free, paleo, and carnivore fad diets, there’s no shortage of guidance on what certain people think others should or shouldn’t eat. Those diets can be confusing, and are often in conflict. Fortunately, a global report published Thursday in The Lancet boils dietary advice down to a few stark facts. One in five people around the world dies an early death each year, and that’s largely a result of one of three very bad diets.
The report shows the results of the Global Burden of Diseases Study, an assessment of how — and how many — people die from disease in countries around the world each year. While it’s no secret that poor diet contributes to poor health, the authors, funded by the Bill and Melinda Gates Foundation, set out to find just how many deaths and lost years of life could actually be attributed to unhealthy eating habits annually.
Using data estimating the eating habits of 195 countries, the team discovered that in 2017, the number of deaths due to poor diets reached 11 million. They also estimated “disability-adjusted life years,” or DALYs, a metric for every lost year of “healthy” life per person. Because of poor diet, a total of 255 million DALYs were lost in 2017.
“Poor diet” can mean a lot of things, but the study allowed the authors to boil it down to three major inadequacies: too much salt, not enough whole grains, and not enough fruit. In 2017, high intake of sodium was responsible for 3 million deaths worldwide, low intake of whole grains also led to 3 million deaths, and low intake of fruits led to 2 million deaths. Other issues included diets that didn’t have enough nuts and seeds, vegetables, omega-3s from seafood, or fiber, along with many other components.
Of the three major dietary issues, too much salt was the major killer.
Salt Is Responsible for Half of Diet-Related Deaths
To study how much salt people around the world were consuming, the team pulled together data from each country, measuring “24 h urinary sodium,” or the amount of salt that’s excreted in the urine over a day. To show how that’s related to disease, they first estimated the relationship between urinary sodium and blood pressure (it’s well-established that too much salt raises blood pressure), and then linked rises in blood pressure with disease risk.
Simply put, this data revealed that we are having too much.
“In 2017, more than half of diet-related deaths and two-thirds of diet-related DALYs were attributable to high intake of sodium,” the team writes. Sodium was the top risk factor for East Asian countries like China, Japan, Indonesia, and Thailand, nations whose cuisine is heavily reliant on salty sauces and pastes.
The problem with too much salt, according to the American Heart Association, is that it’s very taxing on the cardiovascular system. When you eat a salty meal, the body finds ways to “dilute” the blood so its salt concentration stays normal, and the easiest way of doing this is to retain water. Doing that means the volume of blood in the bloodstream increases, which puts a strain on the vessels and heart. (Imagine a garden hose that’s turned on but closed off at the nozzle end; the pipe will stretch uncomfortably as water pressure builds inside.) Over time, that strain on the blood vessels will cause them to stiffen, which can lead to high blood pressure, heart attack, and stroke.
While most nations kept statistics on the amounts of certain foods that citizens were eating, few had statistics on their sodium intake, the authors note. In light of the data showing how dangerous too much salt can be, they strongly advise nations to do so — and find ways to restrict its use.
Whole Grains and Fruits
Diets lacking whole grains were responsible for 82 million lost years of healthy life, and those lacking fruits were responsible for 65 million, the authors write. These foods are known to do the opposite of what sodium does: improve heart health.
The “planetary health diet,” released in January by a team of 37 international scientists commissioned by The Lancet and the global nonprofit EAT, explained why whole grains and fruit are so necessary.
“High intake of whole grains and fibre from grain sources has been associated with reduced risk of coronary heart disease, type 2 diabetes, and overall mortality,” they wrote. Of fruit, they noted its essential role in providing micronutrients as well as in preventing cardiovascular disease.
How to Eat Better
While the dietary insufficiencies that are the greatest risk factors vary by country, the report notes that, “Globally, consumption of nearly all healthy foods and nutrients was suboptimal in 2017.” Fixing those issues requires changing the diet — a change that isn’t as simple as just rewriting a grocery list.
Socioeconomic factors, both regional and global, can seriously hamper a person’s ability to access lower-sodium food, whole grains, and fruits, even if they want to. In January of this year, another Lancet commission pointed a finger at Big Food — the multinational food industry, which includes companies like PepsiCo, Nestle, and Tyson Foods — for interfering with government health and food policies that could rectify those socioeconomic inequalities.
For those of us who have the ability to change our diets, however, the guidance is clear, and is largely summed up in the seven-word “Eater’s Manifesto” written by the acclaimed food writer Michael Pollan in 2008: “Eat food. Not too much. Mostly plants.” A nine-word 2019 update might add: “Less salt.”