Fast food restaurants have sought a healthier image in recent years by featuring more salads, veggie burgers, and even grilled chicken nuggets. But has the fare really improved nutritionally?

To find out, researchers tracked changes in hundreds of menu items at 10 popular chains at three points over the past three decades: 1986, 1991, and 2016. The restaurants included McDonald’s, Wendy’s, Burger King, Carl’s Jr., Dairy Queen, Arby’s, KFC, Long John Silver’s, Hardee’s, and Jack in the Box. Among the key findings, which were reported earlier this year in the Journal of the Academy of Nutrition and Dietetics:

Overall, the number of entrées, sides, and desserts more than tripled between 1986 and 2016, with a net increase of 23 items per year.

• Portion sizes of entrées and desserts went up significantly (by about a half-ounce and 1 ounce per decade, respectively).
• Calories increased across the board—most in desserts (62 calories per decade), followed by entrées (30 calories per decade)—largely because portion sizes got bigger. The calories in an average entrée rose from 326 in 1986 to 416 in 2016. Order dessert and, on average, you will get nearly 200 more calories than 30 years ago (420 versus 234). Calories in sides increased slightly (14 calories per decade).
• Sodium increased by about 110 milligrams per decade in entrées, on average, and by 94 milligrams per decade in sides (the Daily Value for sodium is 2,400 milligrams). This increase in sodium was significant even when the amounts were adjusted for increased portion sizes or calories.
• Calcium increased in desserts by nearly 40 milligrams per decade, on average (the Daily Value is 1,000 milligrams), in part because of the increase in portion sizes. (But there are, of course, far better sources of calcium than fast food.)

This national survey of fast food across the U.S. is the longest and largest to date, and its results “indicate a broader range of unhealthy changes in fast food offerings than previously indicated,” the authors wrote. The findings are important given that nearly 40 percent of Americans eat fast food on any given day, according to CDC stats, and since eating away from home is associated with poorer diets—and higher calories—overall.

On a bright note, other recent research suggests that fast food restaurants are lowering the calories in some items as a result of the mandatory menu labeling legislation that went into effect last year as part of the Affordable Care Act.