The #1 Swap That May Decrease Your Risk of Heart Disease and Diabetes, According to a New Study

Through the years, nutrition recommendations have changed numerous times as evidence from the research mounted in one direction or the other. For example, we used to think that the cholesterol in the foods we eat added to the cholesterol in our bodies. We now know that if it affects it at all, it’s minimal. 

And remember the no-fat fad? We now know that some fat in our diets is necessary. 

But research on what types and how much fat is necessary is still not totally conclusive. For example, there is evidence that some types of saturated fat aren’t as harmful as other types—like the kind in cheese and eggs compared to those in highly processed foods. Or perhaps it’s actually other components in the food that protect us from any harmful effects of the saturated fat in the food—more research to come. Either way, this doesn’t mean you should eat unlimited amounts of them. 

In fact, a new study published on July 11, 2024, in Nature Medicine looked at what happens when saturated animal fats (like butter) are swapped out for plant-based unsaturated fats (like olive oil). Let’s see what they found.

How Was This Study Conducted & What Did It Find? 

This study was conducted differently from typical studies in that it used four different study cohorts instead of one. From the first cohort, which was an original study, researchers established what they called a multi-lipid score (MLS). There are over 100 different types of lipids. Lipid levels are tested via bloodwork. In this study, called the Dietary Intervention and Vascular function (DIVAS) trial, researchers took 113 participants and randomly split them in half. For 16 weeks, one group ate a diet high in saturated animal fats, while the other group ate a diet rich in plant-based unsaturated fats. What they found in this study was that higher MLS correlated with healthier blood fat profiles, higher intakes of plant-based unsaturated fats and lower intakes of animal-based saturated fats. 

Researchers then computed participants’ multi-lipid scores in three other large, long-term studies that had previously been done to see if higher MLS correlated with reduced risk of heart disease and type 2 diabetes. These studies were called the European Prospective Investigation into Cancer and Nutrition (EPIC)-Potsdam study, the Nurses’ Health Study (NHS and NHSII), and the PREDIMED trial. 

These three other studies included large cohorts of participants and initially healthy individuals who were followed for several years. This gave researchers a chance to see what participants’ diets were composed of, what their lipid profiles were—so they could compute multi-lipid scores based on their blood levels—and whether or not they ended up with heart disease and/or diabetes. 

What researchers found was that participants with a higher MLS—which indicates a diet containing lower levels of saturated fat and higher levels of unsaturated fats—had a substantially reduced risk of developing cardiometabolic diseases, including heart disease and diabetes.

Specifically, in the EPIC-Potsdam study, participants with higher MLS had an estimated 32% lower risk of heart disease and 26% lower risk of type 2 diabetes. 

The NHS cohort suggests that improving dietary fat quality over 10 years was associated with about a 43% lower risk of developing diabetes.

In considering the PREDIMED study, researchers looked at participants who had low MLS at the beginning of the study, indicating a diet high in saturated fat and low in unsaturated fats. They wanted to know if improving diet quality—specifically, switching to a Mediterranean diet eating pattern—would help prevent disease. They found that switching from a diet high in saturated fat to a Mediterranean diet eating style, which includes lots of unsaturated fats, helped prevent the onset of diabetes.

How Does This Apply to Real Life?

According to the Centers for Disease Control and Prevention, heart disease is the No. 1 cause of death and disability globally, including in the U.S. And diabetes is a risk factor for heart disease, especially when blood sugar levels are not well-managed. 

A Mediterranean diet eating pattern has been shown to have many benefits, including reducing the risk of heart disease, stroke and type 2 diabetes. Engaging in this way of eating also reduces cognitive decline, bone loss and inflammation. Altogether, following a Mediterranean diet may help you live longer. 

The Mediterranean diet includes lots of fruits, vegetables, nuts, seeds, lean proteins, legumes, whole grains and healthy fats. If you’re not ready to jump into a full Mediterranean diet eating style, start with simple swaps by trading foods you typically eat that are high in saturated fat with foods that are high in unsaturated fats. For example, instead of slathering butter onto your toast, swap the butter with mashed avocado or peanut butter. Instead of butter and sour cream on your baked potato, try a drizzle of garlic-infused olive oil and a dollop of plain Greek yogurt. Switch out one dinner with red meat each week for a heart-healthy salmon meal. Have a handful of nuts in place of chips for your snack. 

The Bottom Line

This study adds to the evidence suggesting that replacing foods high in saturated fats with foods high in heart-healthy unsaturated fats may help reduce the risk of heart disease and diabetes. A Mediterranean diet eating pattern has consistently been shown to reduce inflammation and disease risk. Instead of trying to overhaul your routine, simply swap some foods that are high in saturated fat with foods that are high in unsaturated fat, like nuts and nut butters, seeds, oils and seafood. Small swaps will eventually add up to big changes that may help reduce your risk of disease, improve your quality of life and increase your chances of living longer.