Filled with empty calories and ultra-processed, fast food may increase the risk of obesity and cancer. While fast-food chains have ostensibly been trying to offer more healthful options, a new study finds that the health impact of their menus has not improved—to the contrary, in fact.

Data from the Centers for Disease Control and Prevention (CDC) indicate that, between 2013 and 2016, 36.6% of adults in the United States ate fast food on any given day. Moreover, according to a study conducted by University of Connecticut researchers in 2018, around 74% of parents purchase unhealthful foods for their children in fast-food restaurants. This, the investigators noted, is despite the fact that, from 2013 onward, some of the most popular fast-food chains committed to offering more healthful options in their children's menus.

Now, a new study suggests that most fast-food restaurant menus have not, in fact, become more healthful overall, despite the addition of some arguably more wholesome choices. The researchers analyzed the variety, portion size, and nutrition of entrées, sides, and desserts offered by 10 of the most popular fast-food chains in the United States over a period of roughly three decades, based on the menus they made available at three points in time: in 1986, 1991, and 2016. The team analyzed menus from Arby's, Burger King, Carl's Jr., Dairy Queen, Hardee's, Jack in the Box, KFC, Long John Silver's, McDonald's, and Wendy's.

In the study paper—which appears in the Journal of the Academy of Nutrition and Dietetics—the investigators explain their focus, noting that, "These restaurants were chosen because the nutritional information on the key nutritional variables of portion size, energy, and sodium were available for each of the 3 years being analyzed."

"Given the popularity of fast food, our study highlights one of the changes in our food environment that is likely part of the reason for the increase in obesity and related chronic conditions over the past several decades, which are now among the main causes of death in the US," says lead investigator Megan McCrory, PhD

Fast food still fuels chronic conditions

The researchers looked at how entrées, sides, and desserts changed on these fast-food restaurants' menus over the 30-year span. More specifically, they paid attention to changes in caloric content; portion size; energy density; and sodium, iron, and calcium contents.

McCrory, an associate professor at Boston University in Massachusetts, and the team accessed the relevant data through The Fast-Food Guide, which was published in 1986 and 1991, and via resources available online for the year 2016. First, the researchers observed that the variety of foods that these restaurants offered increased at a high rate of 22.9 items, or 226%, per year. However, as the variety increased, so did the caloric content of the food items on offer, as did portion size.

Thus, among entrées, sides, and desserts, calories saw a sharp increase. The largest such rise was in the dessert category, with an increase of 62 kilocalories every 10 years. Next came entrées, which saw an increase of 30 kilocalories per decade. The team found a link between higher caloric content and larger portion sizes. These increased by 13 grams per decade for entrées and 24 grams per decade for desserts. At the same time, sodium (salt) content also went up among each food type.

"Our study offers some insights on how fast food may be helping to fuel the continuing problem of obesity and related chronic conditions," the lead researcher concludes, adding:

"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."

—Megan McCrory, PhD

A long way to go for fast-food chains

McCrory and the team also note that 4 of the 10 fast-food chains also provided information on the calcium and iron content of items on their menus over the past three decades. The researchers acknowledge that the two essential nutrients—which play key roles in bone and blood health — are much more present in fast food now than they were 30 years ago. Specifically, entrées and desserts now have significantly higher calcium contents, and iron is more abundant in desserts.

However, McCrory stresses that fast food should not be the first port of call for people looking to increase their calcium and iron levels, since these nutrients are available in unprocessed or minimally processed foods, such as seeds, dairy products, and fish.

"We need to find better ways to help people consume fewer calories and sodium at fast-food restaurants," says McCrory. "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 adds.