There is no one-size-fits-all approach to dieting (although that would make things so much easier). Likewise, different diets lead to different results. For instance, intermittent fasting has been scientifically linked to weight loss and reduced inflammatory activity. And previous studies have touted low-fat and low-carb diets for lowering "bad" cholesterol. While omitting fatty, high-carb foods would, theoretically, also benefit the heart, experts have been hesitant to support these claims.
A new study now indicates that prioritizing healthy, high-quality foods has just as big of an impact on heart health as restricting carbohydrates and fat, especially when it comes to reducing cardiovascular disease risk.
"We found that what you eat on low-carb or low-fat diets matters just as much as the diet itself," lead author Zhiyuan Wu, PhD, a postdoctoral fellow at Harvard T.H. Chan School of Public Health, said in a news release.
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Consuming high-quality nutrients can help lower cardiovascular risk.
The observational study involved 156,353 women and 43,430 men, for a total of 199,783 participants. Their dietary habits were tracked over three decades via detailed questionnaires that assigned points to specific foods within low-carb and low-fat diets.
Foods containing high-quality nutrients had a higher score value. This included carbohydrates, fats, and proteins from whole grains, fruits, vegetables, nuts, and legumes. Meanwhile, unhealthy diet choices (i.e., consuming foods with low-quality nutrients) had a low score value. This category encompassed carbohydrates from potatoes and refined grains, and saturated fats and proteins from animal products.
During this time, researchers were also testing participants for heart disease and monitoring their metabolic regulation. To assess the latter, they measured "hundreds of blood metabolites," which enabled them to "better understand the biological effects of these diets," explained Wu.
The final verdict? Sticking to a low-carb or low-fat diet rooted in healthy food choices (AKA, high-quality nutrients) led to a reduced risk of developing coronary heart disease. According to the release, "These healthy diet patterns, whether low-carbohydrate or low-fat diet, lowered the risk of developing heart disease by about 15 percent." Meanwhile, those who consumed foods with low-quality nutrients, on either diet routine, experienced an increased risk.
"Our findings suggest that improving food quality is crucial for improving heart health," Wu said. "Regardless of whether someone follows a low-carbohydrate or low-fat diet, emphasizing whole, minimally processed and plant-based foods and limiting refined grain, sugar and animal foods, can significantly reduce the risk of coronary heart disease."
The takeaway:
Adhering to a low-carbohydrate or low-fat diet can do wonders for your health. However, when it comes to taking care of your heart, this study proves that consuming foods with high-quality nutrients is what matters most.
"For those looking to improve their diet, the researchers suggest focusing on adding more whole grains, fruits, vegetables, nuts and legumes while cutting back on processed meats, refined carbs and sugary foods. They note that it is also important to check food labels and be mindful of added low-quality ingredients, such as added sugars in juices and processed snacks," per the release.
Wu is presenting his team's findings at the American Society for Nutrition’s annual NUTRITION 2025 summit.
