Why Fat Is Sometimes More Heart-Healthy Than Carbs

Pictured Recipe: Salmon & Avocado Salad

Fat, heart health and carbs are all topics in nutrition that have been up in the air over the last several decades. One relatively consistent piece of advice has been that reducing your intake of saturated fats can help reduce the bad cholesterol in your blood, which can lower your risk for heart disease. However, that isn't quite as simple as it sounds. What you replace saturated fats with in your diet matters. We dove into the science for the do's and don'ts of lowering your saturated fat intake, and found that not all carbs are created equal for your heart.

Swapping in Other Kinds of Fats

So, for starters, what are saturated fats? All fats, saturated and unsaturated, are made up of the same building blocks: carbons and hydrogens. Saturated fats have more hydrogens, so their chains are stiffer. This is one of the reasons they are solid at room temperature. These saturated fats can increase the "bad" cholesterol, low-density lipoproteins (LDL), in your blood. Over time, increased LDL can lead to atherosclerosis, which is a heart disease categorized by plaque buildup in the arteries. Foods that are high in saturated fats include some cuts of red meat, butter, lard, palm oil, palm kernel oil and coconut oil.

More malleable unsaturated fats come in a few forms. Monounsaturated fats have fewer hydrogens than saturated fats, due to their chemical structure, so foods with high monounsaturated fat content are often liquid at room temperature but solid when chilled. Food sources include canola oil, safflower oil, avocados, peanut butter and many nuts and seeds. Polyunsaturated fats have even fewer hydrogens than monounsaturated fats. Foods that are high in polyunsaturated fats include soybean oil, corn oil, walnuts, sunflower seeds and tofu. Olive oil is particularly heart-healthy as it contains both mono- and polyunsaturated fats.

Swapping out saturated fats for polyunsaturated fats, particularly omega-3 fatty acids like those in salmon and walnuts, has been shown to be the most beneficial move for heart health. However, swapping out saturated fats for any unsaturated fats can reduce your risk of heart disease. Some studies show pairing unsaturated fats with lean protein can be beneficial as well. Stick with plant-based protein sources, like legumes, nuts, tofu and eggs, for the most bang for your buck.

Swapping in Carbs

You probably have had an inkling that refined carbs, like sugar, white bread and candy, aren't the best for your health. But can they really be worse than saturated fat when it comes to heart health? Turns out, the short answer is yes. Studies have found that replacing saturated fats with foods with a high glycemic index, meaning refined carbs that are quickly absorbed (like sugar or white bread), can actually increase risk of heart disease. A review in the American Journal of Clinical Nutrition found that while both saturated fats and refined carbs increase risk of heart disease, refined carbs also cause greater metabolic damage which could make them worse for your overall health.

On the bright side, several studies have found that replacing saturated fats with complex carbs, like whole grains, improves heart health, especially for people with obesity or diabetes. A review in the Journal of the American College of Cardiology found that pairing complex carbs with unsaturated fats had the most beneficial impact on heart health.

Bottom Line

Eating a variety of healthy foods from all food groups is the best way to have a healthy diet—and extreme intakes of any nutrient are not beneficial, whether it is fat or carbs. Science supports that replacing saturated fats with unsaturated fats can actually be better for your heart than replacing them with refined carbs. Pairing unsaturated fats with complex carbs was shown to have the most heart-healthy benefit. This is not to suggest you should never eat any saturated fat (trust me, we love butter and bacon too), but it is important to take stock of how much you are eating and to treat high-saturated fat foods as sometimes foods rather than frequently eating them. For more information, check out our Heart-Healthy Diet Center.