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While fast food is indeed fast, and often delicious, there’s no secret that it isn't particularly good for you. What you might not know is how much worse it is now than it used to be. In the longest-running and most thorough study of its kind, researchers from Boston University and Tufts analyzed menu items from top fast-food chains like McDonald's, Burger King, Dairy Queen, KFC, and Wendy's. The study, published earlier this year by the Journal of the Academy of Nutrition and Dietetics, uses data from 1986, 1991, and 2016 to create a picture of how fast food has evolved over the past three decades.

Everything has gotten bigger — much bigger.

The most popular fast-food restaurants in America have added a heap of selections to their menus since the mid-’80s. The number of offerings grew by 226 percent, the research shows, an average of nearly 23 menu items every year.

Photo credit: Courtesy of chilis.com

It’s not only the menus that are bigger. One of the main reasons fast food is less healthy than it was 30 years ago is portion size. The weight of an average entree increased 39 grams — or 13 extra grams per decade.

It's probably not surprising that, as entrees got bigger and weighed more, the number of calories increased. The average fast-food entree gained 30 calories per decade, or 90 calories from 1986 to 2016.

Fast-food desserts also grew in weight and calorie count, and on a much larger scale. The average dessert gained an average of 71 grams and a full 186 calories over the years.

Calories and sodium increased even when portion sizes didn't.

Photo credit: Courtesy of 375fries.com

Side orders such as fries, chips, and soup hold the rare distinction of remaining about the same size over the past 30 years. But today's average side order manages to pack in 42 more calories than its 1986 predecessor. In all, the average modern fast-food meal of an entree and a side accounts for 40 percent of a recommended daily intake of 2,000 calories.

The amount of sodium also went up across the board. In 1986, the average entree contained 27.8 percent of the recommended daily intake. By the time the study was complete, that number had jumped to 41.6 percent. Sodium content also increased in desserts and sides, even though portions didn't get much bigger.

There was a flicker of good news.

Fast food has gotten a slight boost in some beneficial minerals over the past 30 years. Today's drive-through dessert has 3.9 percent more calcium than it did three decades ago, the study shows, and there’s 1.2 percent more calcium in entrees. There's also about 1.4 percent more iron in fast-food desserts now.

Of course, that’s not nearly enough to keep researchers from concluding that consumers should reduce the number of calories they get from fast food. On any given day, more than one in three Americans eats fast food, according to the Centers for Disease Control and Prevention.