New Yorkers who like to eat out have likely become a tad healthier in recent years—without even knowing it. It’s not because expensive salad bowls are monopolizing the city (though they are). Rather, it’s because New York City enacted an unprecedented ban on trans fats in restaurants in 2006—and researchers can now say that policy had definitively positive long-term health benefits.
In a new paper published in the American Journal of Public Health, scientists found that trans fatty acid (TFA) levels in the blood of New York City residents fell by more than half in the decade between 2004 and 2014, an average decrease of 57 percent citywide. That’s only slightly more than the 54 percent drop seen nationally between 2000 and 2010. But what’s really revealing is that diners who eat out more often saw more impressive results. Those who ate out less than once a week saw their TFA levels decrease by 51 percent on average, while those who ate out four times a week or more saw an even larger decrease of about 62 percent.
According to the study, that disparity is a sign that the trans fat ban was successful. Though TFA consumption has decreased across the country in the timespan studies, the authors write that “the differential decline … among high restaurant frequenters suggests an independent impact of [New York’s] TFA restriction.”
The study’s data sets come from surveys of more than 3,000 New York City residents, 20 years of age and older, who provided blood samples and information about their health and dining habits. The first set of participants was studied in 2004, and the second between 2013 and 2014; researchers then selected 250 blood samples from each set at random and graphed trans fat levels to rates of dining out.
The new study’s authors admit, though, that New York can’t take all the credit. TFA consumption has declined in America overall since 2004.
Think back to the aughts, which were a significant turning point in American food culture. The period saw new levels of attention to healthful eating and the role that food corporations play in shaping people’s diets. The nascent organic industry was beginning to blossom. The term “locavore” had just been coined. And muckraking food documentaries, like Morgan Spurlock’s 2004 film Super Size Me and 2008’s Food, Inc., were a huge hit with the public. (A Super Size Me sequel was axed in 2017 after Spurlock admitted to acts of sexual misconduct and acknowledged a date rape accusation.)
It was within that paradigm-shifting context that the health risks of trans fat consumption caught on for the first time. Though TFAs occur naturally in small amounts in many animal products, including butter, they were introduced en masse into the food system in the 20th century, after scientists discovered that adding hydrogen to vegetable oil could solidify it and lengthen its shelf life. This led to the birth of partially hydrogenated vegetable oils, which were cheaper than solid animal fats and, thus, added to a wide range of food items, including breads, baked goods, and snacks. But at the turn of the century, scientists began to link the consumption of trans fat to an increased risk of heart disease.
FDA’s decision, however, came much later than New York’s, and residents of the Big Apple seem to have genuinely benefitted from the city’s early action.
“Diners were at a distinct disadvantage because there were no labeling requirements in restaurants,” says Dr. Sonia Y. Angell, deputy commissioner at the New York City Department of Health and Mental Hygiene, and one of the study’s authors. “[In 2006], we found that about half of the restaurants in New York City were using trans fats for frying, cooking, baking, or in their spreads. That was problematic […] but it was also promising to us. Because while half of the restaurants were using it, half of them weren’t, which made us also realize that this was something that we could move out of restaurant foods.”
When the city’s health department enacted a citywide ban on trans fat use in restaurants in 2006, the regulation was wide-ranging, affecting all sit-down establishments, as well as catering, delivery, and take-out services. The policy prohibited food providers from using ingredients that contained more than 0.5 grams of trans fat per serving (for reference, that’s how much trans fat a serving of butter contains). Pre-packaged foods—say, chips sold at delis—were exempt. The city’s ban was phased in completely in 2008.
“Even though [TFAs are] moving out of the food supply at large, we think this is an important finding, because it really argues that restaurant foods are an important source of nutrition—particularly in New York City for a large group of people,” Angell says. “By developing policies like this that target the restaurant environment, we can have a really important direct effect on the nutrition of of diners.”
The trans fat ban is just one of many different policies that local jurisdictions can put in place to encourage residents to live healthier lives. Soda taxes and calorie labeling are well-documented, if contentious, examples. But they’re also a bit different.
“People don’t choose trans fat on the menu, whereas you choose a soda,” Wendy McKelvey, another author of the study points out. And, whereas calorie counts can incentivize eaters to pick certain foods over others, trans fats don’t need to be added to food.
“When you take trans fat out of the food supply, people don’t have to deliberate between whether or not they buy something that has trans fat in the product,” Angell says. “And therefore it takes that extra level of individual energy to try and eat healthy out of the formula. It makes sure that everybody can eat healthy and that that’s something that is really important.”
This study also gives us a glimpse into how much healthier all eaters in the U.S. may soon become, thanks to FDA’s nationwide ban. Ten years from now, New Yorker or not, you might be a little better off without even knowing it, too.