Unhealthy diets led to 11 million deaths in 2017 — brought about by health issues like cardiovascular disease, cancers, and type 2 diabetes. This makes poor diet responsible for roughly one in five deaths worldwide, which is more than any other known health risk, including tobacco use.

These findings came out of a recent study published in The Lancet. The study took a deep dive into global eating habits among adults over age 25 living in 195 countries. Reanalyzing data from previous studies ranging from 1990 to 2017, the researchers were able to estimate the influence of diet on mortality rates in different parts of the world and across varying demographics.

Breaking down dietary data

Researchers first set out to determine a target consumption range for 15 dietary risk factors, a group of nutrients and foods that met criteria established by a 2017 study. They then looked at what daily intake levels presented the lowest risk of diet-related health concerns and calculated a mean intake level for each ideal range.

They found that improper amounts of three dietary components — salt, whole grains, and fruit — caused more than 50% of diet-related deaths in 2017.

Hold the salt

High sodium intake was responsible for an estimated 3 million deaths, mostly among men and seniors. On average, daily consumption of sodium around the world was 86% above what the researchers considered to be optimal: 2,500 mg. (The FDA recommends a Daily Value of less than 2,300 mg.)

Add more whole grains

The study’s analysis determined an ideal intake of 125 g of whole grains a day, from sources like cereal, oatmeal, pasta, bread, rice, and corn. U.S. dietary guidelines suggest 6 oz (over 170 g) of grains per day, and at least half of those (85 g) should be whole grains. But the researchers discovered that the average person gets only 29 g. Low whole grain intake ranked only slightly lower than high sodium for total diet-related mortalities, but it was a leading risk factor across all demographics.

An apple a day

The study calculated a daily recommendation of 250 g of fruit, not including fruit juices or other heavily processed products. (An average of 2 cups of daily fruit is recommended in the United States, and fruit juices may contribute to this.) Lack of fruit contributed to the third-most diet-related deaths (at 2 million).

Low fruit intake was also the leading risk factor in areas scoring 0 on the Socio-demographic Index (SDI). An SDI score of 0 indicates an area with the lowest income per capita, lowest educational attainment, and highest fertility rates.

Other contributors

Diets low in nuts and seeds, vegetables, and omega-3 fatty acids also accounted for a large number of worldwide deaths.

High sugar intake was a concerning factor, too. The average intake of sugar from sugar-sweetened beverages reached 49 g per day, well exceeding the study’s suggested limit of 3 g. Researchers found consumption was highest among young adult populations, tapering off will age. The U.S. Office of Disease Prevention and Health Promotion advises that added sugars make up no more than 10% of daily caloric intake. But added sugars on average contribute to 270 calories per day (13% of daily intake) among Americans, and sugary drinks make up nearly half of those calories.

Challenges in adopting nutritionally balanced diets

The Lancet study notes that there isn’t enough evidence yet to determine the agricultural and environmental impacts of a worldwide shift toward ideal nutrition. However, one of the study’s co-authors, Evan Fraser, told NPR that a dietary shift this widespread would require significant systematic changes. “We simply can’t all adopt a healthy diet under the current global agriculture system. We have a mismatch between what we should be eating, and what we’re producing.”

We would also have to overcome issues like food insecurity. A recent USDA study found that factors like SNAP participation and limited access to quality grocery stores correlate with lower nutritional scores. Families continue to struggle against barriers such as low food budgets, unreliable transportation, and lack of nearby stores selling diet-friendly items like fresh produce, whole grains, and seafood.

Why most diet-related campaigns are ineffective

There’s an undeniable relationship between poor nutritional choices and declining physical health. And the authors of the report have some ideas for addressing it.

They suggest looking beyond salt, sugar, and fat intake and focusing policies and public education efforts on healthy levels of other important food items — whole grains, fruits and vegetables, nuts and seeds, and sources of omega-3 fatty acids.

The study also analyzed past dietary modification efforts, such as mass media campaigns, label changes, wellness programs, and taxation. When targeting specific ingredients, such efforts proved to be cost-effective, but researchers discovered some limitations:

  • The diet improvement results of most of these efforts were underwhelming.
  • There’s little evidence to support that the same campaigns that showed promise for things like salt and sugar would also work for whole grains, processed meats, and other nutritional health factors.
  • Most of these dietary interventions based cost-effectiveness on assumptions rather than feedback from key stakeholders like consumers and food industry professionals.
  • The push to change food policies, such as banning or limiting certain ingredients, rarely resulted in the adoption of new regulations.
  • Most of the diet-related campaigns were aimed at consumers, neglecting to include farmers, food processors, and distributors in reformation goals.

These findings make one thing clear — enhancing nutrition on a global level is no small feat. It’s a complex puzzle that can’t be solved from a singular angle. Surrounding issues such as food access, federal policies, agricultural practices, and product labeling must all come into play.

But can it be done? The study authors seem to think so, as long as everyone’s at the table. “Improving diet requires active collaboration of a variety of actors throughout the food system,” the report concludes, “along with policies targeting multiple sectors of the food system.” It’s going to take all parties — from lawmakers to consumers to farmers, processors, and retailers — to develop and implement successful strategies for combating life-threatening diet-related illnesses.