Low-fat vs. Mediterranean: Which diet is better for your heart?

"Cut back on fat."

It is advice that has long dominated dietary guidance — but it may not be the best approach. The notion that fat is inherently bad, or must be avoided at all costs, is giving way to a focus on fat quality. That shift is reflected in both recent research and the US government's latest dietary guidelines.

The American Journal of Clinical Nutrition recently published a joint US-European study finding that a traditional Mediterranean diet reduces heart disease risk more effectively than a low-fat diet. Researchers tracked the diets of 12,197 adults aged 55 to 80 with cardiovascular risk factors. The cardiovascular disease risk rate was 35.9 percent among those on a low-fat diet, compared with 28.2 percent among those following a Mediterranean diet.

The Mediterranean diet emphasizes foods rich in unsaturated fatty acids — olive oil, fish and nuts, among others. The findings suggest that selectively choosing healthy fats, rather than simply cutting total fat intake, may be more effective for heart health.

A similar effect emerged in research published in Current Problems in Cardiology in 2024. A follow-up study of 10,054 participants found that those on a Mediterranean diet had lower mortality rates from cardiovascular disease — particularly heart attacks and strokes — than the control group.

Nutritionists caution that cutting fat indiscriminately, without a clear plan for what to eat instead, may not benefit heart health.

The same message runs through the Dietary Guidelines for Americans 2025-2030, released earlier this year. The new guidelines move away from the old directive to reduce total fat intake, urging people instead to distinguish between types of fat and choose accordingly.

Previous guidelines capped fat consumption at 20 to 35 percent of total daily calories. The updated version steps back from strict fat reduction, allowing fat from whole foods within an appropriate range.

Processed oils — such as cooking oils — and trans fats produced during food processing are still recommended for reduction. The longstanding rule that saturated fat, even from whole foods, should account for less than 10 percent of total calories remains in place.

The new guidelines call for a clear distinction between healthy fats and those to avoid, based on criteria such as whether a fat is saturated or unsaturated and whether it comes from a whole food or a processed source.

US health authorities said healthy fats are found in a wide range of foods — including olives, meat, avocados and nuts — and urged people to choose quality fats from real food.