The vast majority of Americans are eating much more salt than is good for them, the U.S. Centers for Disease Control and Prevention said in a report released Thursday alongside the 2015 Dietary Guidelines for Americans. This excessive consumption is hardly a new phenomenon, and science has for years showed that too much sodium can have detrimental effects on health. But for the 89 percent of Americans who consume more sodium than the maximum of 2,300 milligrams per day recommended in the 2015 Dietary Guidelines, reducing that amount will be a lot more challenging than just cooking without salt. Here's why.

Sodium is ubiquitous. It's not just in the salt shaker sitting on the kitchen table. Significant amounts are also added to processed foods. "The top sources of sodium in the U.S. diet include breads and rolls, deli meats, pizza, poultry, soups, sandwiches, cheese, pasta dishes, meat mixed dishes, such [as] tomato sauce, and savory snacks," the CDC's report said. In other words, even people who consciously avoid cooking with salt or sprinkling it across their dinner plates may be taking in more than they think. 

Consuming too much sodium poses several health risks, from high blood pressure to cardiovascular disease to strokes. Yet the fact that these dangers have long been well documented hasn't changed the amount of salt people eat or the amount used in food processing. By comparing its newest findings — which were an analysis of data from more than 14,000 people who took part in a national survey from 2009 to 2012 — with previous ones, the CDC determined that "overall sodium consumption and the concentration of sodium in foods consumed have not changed over the past decade." Even among adults who have high blood pressure — that's a third of adults in the U.S. — 86 percent still consume too much sodium, the CDC said.

And while the 2015 Dietary Guidelines for Americans has been slammed by critics for caving to the food industry and failing to use language that targets specific foods, like red meat, the CDC's report referred specifically to that industry and its contributions to Americans' growing health problems. "Reducing sodium added to foods by food manufacturers and restaurants is a fundamental public health strategy for reducing the intake of sodium," the report said. It added that not only would "changes in individual lifestyles" help people consume less sodium, but so would changing "how foods are produced."

In 2014, a survey of 1,000 people conducted by the American Heart Association found that 97 percent either underestimated or had no idea how much sodium they consumed each day. Those who underestimated were typically off by 1,000 milligrams.

“It’s challenging for Americans to stick to sodium intake recommendations because most of the sodium we eat in this country is added to our food before we buy it,” Elliott Antman, the president of the American Heart Association, said at the time. “In order to really make a difference in the health of all Americans, we must reduce sodium in the food supply through the support of food manufacturers, food processors and the restaurant industry.” According to the AHA, 75 percent of sodium in Americans' diets comes from processed foods. Even bread, pasta and cereal, not typically regarded as salty, can contain sodium.

Foods like soups and sauces can be culprits, as well, U.S. Secretary of Health and Human Services Sylvia Mathews Burwell pointed out Thursday in a call with reporters. Highlighting the main points in the newly issued dietary guidelines, she said Americans should eat more fruits and vegetables and more whole grains. "By focusing on small shifts in your diet," she said, "eating healthy becomes more manageable.”

But when sodium is everywhere — a slice of bread can have as much as 230 milligrams of sodium (10 percent of the recommended daily maximum) while a cup of canned chicken noodle soup might have 940 milligrams of the stuff — eating healthy may depend not just on small shifts in individual behavior but also, critically, on sea changes in powerful industries throughout the country.