If you’re confused about healthy dietary fats, there’s good reason. Recommendations about fat have undergone a seismic transformation in the past few years—and the aftershocks continue. Experts still bicker, but the emerging hypothesis is this: In moderation, fat is a necessary part of a healthy diet…with one caveat: The fat has to be naturally occurring.

In layman’s’ terms, that means the only fats you need to radically eliminate are artificially produced trans fats, aka partially hydrogenated oils. These are created during a manufacturing process that turns liquid oils into solid fats and are prevalent in margarine, shortening, packaged baked goods (think Twinkies), most microwave popcorn, doughnuts and many fried foods, such as French fries and fried chicken—depending on the oil and the process used.

Eating trans fats increases your risk of heart disease and stroke, and is associated with a higher risk of developing type 2 diabetes, according to the American Heart Association. In fact, the FDA has determined that trans fats are no longer Generally Recognized as Safe (GRAS) and has mandated their removal from all foods by 2018.

The ban, however, does not extend to naturally occurring trans fats, which are found in small amounts in some animal fats, such as beef, lamb and butter. A study in The American Journal of Clinical Nutrition reported that small amounts of natural trans fats don’t increase heart disease risk factors, although large amounts (3.7% or more of total calories) may.

This and other studies are leading many experts to conclude that the saturated fats in meats, dairy products (including butter) and some plant oils (such as coconut) are OK, if eaten in moderation. For example, a 2016 meta-analysis in PLOS One found a relatively small or neutral effect of butter consumption on rates of mortality, cardiovascular disease (CVD) and diabetes. In addition, a 2015 meta-analysis in the British Medical Journal reported a negligible association between saturated fat and mortality or CVD, but a 20–34% risk increase from artificial trans fats consumption.

High Fats to Embrace

While you should avoid trans fats, there are several types of fat that you should embrace, including omega-3 fatty acids, which are vital for brain and heart health, and other unsaturated fats. Healthy sources of dietary fat include: avocados, nuts, seeds, salmon and other fatty fish, and dark chocolate. But because they are high in calories, these high-fat foods should be eaten in moderation and in balance with the other macronutrients: protein and carbohydrates.

Stay Alert!

Scientists suggest you remain vigilant even after the FDA’s ban on trans fats is complete in 2018, in case the replacement ingredients prove to be just as harmful. And if wading through the science seems too tedious, follow this general rule: Stick to natural, whole foods versus processed, packaged ones.