Despite growing awareness of the health risks posed by fast food, and an increased push to add healthier menu items, fast food has actually gotten worse for you in the past 30 years.

That's the finding of a major study conducted by researchers at Boston and Tufts Universities and published Wednesday in the Journal of the Academy of Nutrition and Dietetics, which Boston University says is the most in-depth and longest-period look at how the caloric and nutritional content of fast food has changed over the years.

"Our study offers some insights on how fast food may be helping to fuel the continuing problem of obesity and related chronic conditions in the United States. Despite the vast number of choices offered at fast-food restaurants, some of which are healthier than others, the calories, portion sizes and sodium content overall have worsened (increased) over time and remain high," lead author Dr. Megan A. McCrory of the Department of Health Sciences at Sargent College, Boston University said in an Elsevier press release republished by ScienceDaily.

The researchers looked at meals from the 10 top fast food restaurants, according to sales data, including McDonald's, Dairy Queen and KFC. They took snapshots of menu offerings in 1986, 1991 and 2016 to assess how the portion size and calorie, sodium, calcium and iron content of desserts, entrees and sides had changed over time.

Here are the key findings:

• The number of menu items increased by 226 percent over the study period.
• The portion sizes increased by 13 grams per decade for entrees and 24 grams per decade for desserts.
• Calories increased by 30 calories per decade for entrees and 62 calories per decade for desserts.
• The percentage of recommended sodium based on a 2,000 calorie per day diet increased by 4.6 percent for entrees, 3.9 percent for sides and 1.2 percent for desserts per decade on average.
• Four of the 10 restaurants had data on calcium and iron content. For these restaurants, the percent of daily recommended calcium content of desserts increased by 3.9 percent and the percent of daily recommended iron content increased by 1.4 percent on average per decade

While McCrory said this last change was positive, fast food was still not a good source of these nutrients.

"Although these increases seem desirable, people should not be consuming fast food to get more calcium and iron in their diet because of the high calories and sodium that come along with it," McCrory said in the Boston University press release.

The study acknowledged that fast food is an important part of U.S. eating habits, constituting 11 percent of U.S. daily calorie consumption from 2007 to 2010. Because of this, McCrory said she hoped the study could lead to more research on how to encourage healthier fast food options.

"We need to find better ways to help people consume fewer calories and sodium at fast-food restaurants," she said in the Elsevier release. "The requirement that chain restaurants display calories on their menus is a start. We would like to see more changes, such as restaurants offering smaller portions at ... proportional prices," she concluded.