(Centers for Disease Control and Prevention)

This post has been updated.

More than 90 percent of us consume too much salt (guilty!), which, as you know, contributes to high blood pressure. For some reason, blood pressure varies noticeably by region of the country, so a team of researchers from the Centers for Disease Control and Prevention decided to determine whether there also are regional variations in the amounts of salt in the packaged foods we buy at the supermarket.

They didn't find any. But what they did find, according to a report released Thursday, is a bit sobering: More than half of what we buy contains more than the recommended amount of salt for each serving we consume. Meat and pasta mixed dishes (I assume they're talking about frozen meals and the like; I'm still seeking an explanation) were the top culprits, with better than 80 percent of each containing too much salt in the three regions of the country examined (Pacific, East North Central, and South Atlantic).

[Salt intake is too high in 181 of 187 countries around the world]

Then came pizza (better than 70 percent), soups (more than 60 percent) and cold cuts (50 to 60 percent, depending on the region.).

Of packaged products in the 10 food categories that contribute the most sodium to the American diet, the only ones you can buy without worrying about salt content are cheese, bread and non-sugary snacks. (The full list is in the graph above.)

Processed and restaurant food contributes 77 percent of the sodium in our diets, according to the CDC. (Here's a nice graphic and some info that may surprise you.) Linda Schieb, a CDC epidemiologist and one of the authors of the new study, said it's important to recognize that and shape your diet accordingly.

"We still shouldn't add excess salt," she said in an interview. "But most of the sodium you are consuming is coming from processed [and restaurant] food."

To  meet the Food and Drug Administration's "healthy" standard, breads, cold cuts, soups, cheese, and "savory" snacks must contain 480 milligrams or less of sodium per serving. Pizza, poultry, sandwiches, pasta mixed dishes and meat mixed dishes must have 600 milligrams or less per serving.

According to the FDA, average intake of salt in the United States is about 3,300 milligrams per day, when we should be consuming about 2,300 milligrams (about a teaspoonful). Higher risk groups -- anyone over 51, people with high blood pressure, African Americans -- should be consuming just 1,500 milligrams. This FDA Web page contains some plainspoken advice that's easy to follow. High blood pressured is a cause of heart disease and strokes, which kill 800,000 Americans every year.

[Diets around the world are getting worse, not better]

The researchers concluded that the popularity of national brands probably eliminates any regional variation in sodium consumption via packaged foods, but they did add one footnote: Apparently people in the South Atlantic and East North Central regions enjoy American cheese and "cheese product" more than folks in the Pacific region. American cheese has nearly double the sodium concentration of other cheeses.

Schieb said the researchers were surprised not to find regional differences in the salt in packaged food. The blood pressure differences may be linked to greater obesity, tobacco use and poverty and lower rates of physical activity in some regions, particularly the South, she said.