For years, public-health officials have theorized that phasing out trans fats from the food system would save billions in healthcare costs by reducing heart-disease risk. A new study published today in JAMA Cardiology offers some proof of that theory.

In the hierarchy of dietary fats, trans fats are the worst for your health. Just like saturated fat, trans fats have been found to increase levels of LDL (bad) cholesterol. But trans-fats consumption also has the effect of lowering levels of HDL—the good cholesterol.

And the health risks don’t stop there. Trans fats have also been linked to heart attacks, strokes, type 2 diabetes, inflammation, and even problems with memory and cognitive function.

In the new study, researchers analyzed census and health data from adults in 11 counties in New York state that had instituted a ban on artificial trans fats—those found in partially hydrogenated oils—in restaurant foods, and compared them with data from residents living in 25 counties in New York without such restrictions.

In the years after the bans were implemented, hospitalizations for heart attacks and strokes declined in both groups, but there was a 6.2 percent greater decline in areas where restaurants no longer used trans fat.

“Going into this study we knew the restrictions were only on restaurant food, and that people were still exposed to trans fat in food from grocery stores,” says Eric J. Brandt, M.D., a cardiovascular disease fellow at the Yale University School of Medicine and the lead author of the study. “But our results suggest that broader restrictions on trans-fat intake may have an even greater impact on cardiovascular disease.” 

Trans Fats Are on Their Way Out

Previous research has shown that getting just 2 percent of your daily calories from trans fat—that’s 4 grams for someone eating a 2,000-calorie-a-day diet—can increase cardiovascular-disease risk by 23 percent. With no nutritional upside and plenty of health downsides, experts have determined that there is no safe level of trans-fat consumption.

Fortunately for our hearts, much broader restrictions on trans fats in our food supply are on the way. In 2015 the Food and Drug Administration removed partially hydrogenated oils (the biggest source of artificial trans fats) from the list of ingredients it calls “generally recognized as safe” (aka GRAS) and gave food manufacturers and restaurants three years to phase them out of their products. Many have already done so, and all will have to comply by the scheduled deadline of June 2018.

“Partially hydrogenated oils are created by heating vegetable oil to break hydrogen bonds and create a solid fat,” explains Lauri Wright, Ph.D., R.D., an assistant professor of nutrition at the University of South Florida College of Public Health. “Manufacturers used them because they were cheaper than butter but have a consistency and rich flavor that’s similar to butter.” In their place, manufacturers are now using sunflower, safflower, palm, and coconut oils to create similar tastes and textures. 

What to Look For

Until next summer, when partially hydrogenated oils should all but disappear from our diets, it’s still easy to unwittingly consume more trans fat than you should. “You may still find partially hydrogenated oils in theater popcorn, coffee creamers, baked goods, margarine, and packaged snacks like crackers,” Wright says.

Trans fats are also still present in many restaurant foods. Reading the nutritional information for menu items at restaurant chains such as Applebee’s, Olive Garden, Red Robin, Ruby Tuesday, and TGI Fridays, we found several dishes that contained trans fats in amounts ranging from 0.5 to 3 grams per serving.

Even buying products labeled “trans-fat free” or “0 grams of trans fat” doesn’t guarantee total avoidance. The FDA allows those claims on products that contain less than 0.5 grams of trans fat per serving. But that can add up quickly if you eat more than one serving or several foods with small amounts of trans fats per day.

So for now, the best strategy is to check ingredients lists carefully. “If partially hydrogenated oils are listed, that means the food contains trans fats,” Wright says.