Low-carb and low-fat diets can both protect your heart — but only if they’re built on healthy, high-quality foods.
A new study published today in JACC, the flagship journal of the American College of Cardiology, suggests that when it comes to lowering heart disease risk, the quality of a low-carbohydrate or low-fat diet may be more important than simply reducing carbs or fat.
Researchers found that both eating patterns were linked to a lower risk of coronary heart disease (CHD) when they emphasized nutrient-rich, whole foods. In contrast, versions heavy in refined carbohydrates and animal products were associated with a higher risk of CHD and less favorable metabolic health markers.
Low-carbohydrate and low-fat diets remain popular across the United States. However, their long-term impact on heart health, and how food quality influences outcomes within these diets, has not been fully understood. This investigation is one of the most extensive so far, examining diet quality, metabolomic data, and CHD risk in nearly 200,000 U.S. adults followed for more than three decades.
Why Food Choices Within Diets Matter
“Our findings highlighted that it’s not simply about cutting carbs or fat, but it’s about the quality of foods people choose to construct those diets,” said Zhiyuan Wu, a postdoctoral research fellow at the Harvard T.H. Chan School of Public Health and lead author of the study. “The efficacy of low-carb and low-fat diets in reducing CHD risk is a topic of ongoing debate, and past studies showed mixed findings.”
Wu explained that one reason earlier research may have produced conflicting results is that people can follow a low-carb or low-fat diet in very different ways. Some choose vegetables, whole grains, and healthy fats, while others rely on refined grains, processed foods, and animal-based fats.
