Mediterranean vs. Low-Fat: Which Is Better for Heart Health?
For decades, Americans concerned about heart health were given a familiar message: eat less fat. But a major new study published in The American Journal of Clinical Nutrition [1] reinforces a very different message: the type of fat we eat may matter far more than simply how much fat we eat.
Researchers compared the estimated long-term cardiovascular effects of three healthy eating approaches: 1) traditional low-fat diet, 2) American Heart Association’s dietary recommendations, and 3) Mediterranean diet.
The results were striking.
Among older Americans at high risk for cardiovascular disease, following a Mediterranean diet was associated with an estimated 21% lower risk of cardiovascular disease over 20 years compared with following a low-fat diet. And when researchers looked specifically at cardiovascular death, the difference was even greater: the estimated risk was 40% lower with the Mediterranean diet.
Inside the Study
The study included data from 12,197 U.S. adults participating in two of the country’s best-known long-running health studies—the Nurses’ Health Study and the Health Professionals Follow-up Study. Participants were between 55 and 80 years old and had either type 2 diabetes or at least three major cardiovascular risk factors, such as high blood pressure, high cholesterol, smoking, excess weight, or a family history of coronary heart disease. Researchers used repeated dietary assessments collected over time to estimate what would happen if participants consistently followed one of three dietary patterns for 20 years.
The estimated risk of developing cardiovascular disease was:
- 35.9% with a low-fat diet
- 31.2% following the American Heart Association dietary goals
- 28.2% with the Mediterranean diet
That represents a 7.7% reduction in absolute cardiovascular risk for the Mediterranean diet compared with the low-fat diet. Put another way, the Mediterranean diet was associated with about a 21% lower relative risk of cardiovascular disease. The Mediterranean pattern was also associated with a 28% lower risk of coronary artery disease, 40% lower risk of cardiovascular death, and 23% lower risk of death from any cause compared with the low-fat diet.
Why This Study Matters
We already have substantial evidence linking the Mediterranean diet with cardiovascular health. What makes this new research especially interesting is that it examined its potential impact in a large U.S. population over a 20-year period and compared it directly with both a low-fat approach and the American Heart Association’s food-based dietary goals.
It also reinforces an important evolution in nutrition science.
For many years, dietary fat itself was viewed as something to minimize. Today, we understand that the type and source of fat—and the overall dietary pattern—matter enormously.
The Mediterranean diet isn’t simply a “high-fat” or “low-fat” diet. It emphasizes nutrient-rich foods including vegetables, fruits, legumes, whole grains, nuts and fish, with extra virgin olive oil as a principal source of dietary fat. Rather than simply reducing total fat, the Mediterranean pattern emphasizes unsaturated fats from foods such as olive oil, nuts and fish while limiting less healthful sources of fat.
The message has shifted from simply eating less fat to choosing better fats as part of a healthier overall diet.
The Power of the Mediterranean Pattern
One reason the Mediterranean diet continues to attract scientific attention is that it provides much more than basic nutrients.
Olives, grapes, tomatoes, nuts, herbs, vegetables and other plant foods contain naturally occurring bioactive compounds—including polyphenols and carotenoids—that are being studied for their roles in cardiovascular health, vascular function and protection against oxidative stress. Extra virgin olive oil is particularly distinctive because, unlike chemically refined oils, it retains many of the naturally occurring compounds found in the olive fruit.
But the larger lesson from this research is not about any single food. It is about the dietary pattern as a whole.
The Mediterranean diet replaces many highly processed foods and less desirable sources of fat with whole plant foods, fish and unsaturated fats, while delivering a remarkable variety of naturally occurring bioactive compounds.
Like all observational nutrition research, this study cannot prove cause and effect. However, its findings are consistent with decades of research—including randomized clinical trials—showing that a Mediterranean dietary pattern supports cardiovascular health.
The Takeaway
For years, nutrition advice focused heavily on what we should remove from our diets—particularly fat. Research increasingly points us toward a more useful question:
What kinds of fat—and what kinds of foods—should we eat instead?
This new study provides another compelling answer.
A Mediterranean-style diet rich in extra virgin olive oil, fruits, vegetables, nuts, legumes, whole grains and fish may offer substantially greater long-term cardiovascular protection than simply trying to eat a low-fat diet.
And that may be one of the most important lessons modern nutrition science has taught us:
When it comes to heart health, the type and source of fat—and the quality of the overall diet—matter more than simply counting grams of fat.
To your good health!
--------------
[1] Li Y, Stern D, Martínez-González MA, et al. Cardiovascular Disease Risk Under Low-Fat, Mediterranean, and American Heart Association diets: A Target Trial Emulation in United States Adults. The American Journal of Clinical Nutrition. Published online June 19, 2026.
Cardiovascular disease risk under low-fat, Mediterranean, and American Heart Association diets: a target trial emulation in United States adults - The American Journal of Clinical Nutrition
About the Author
Clare Hasler-Lewis, M.S., Ph.D., MBA, is CEO and Co-Founder of OlivinoLife, Inc., and a nutrition scientist who has spent more than 35 years translating nutrition research into practical health information. She is the author of the Med Diet News series, which explores the latest science on the Mediterranean diet and healthy aging.