Conscious Eating
Conscious Eating
Quality Counts in Heart Disease Prevention
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A 2026 study published in JACC followed nearly 200,000 U.S. adults for up to three decades to examine how low-carbohydrate and low-fat diets relate to coronary heart disease (CHD) risk, and whether diet quality matters more than macronutrient quantity in CHD risk. Using data from the Health Professionals Follow-Up Study and the Nurses’ Health Studies, researchers documented more than 20,000 CHD cases and evaluated participants’ diets based on carbohydrate content, fat content, and food quality.
Participants were scored on different versions of low-carbohydrate (LCD) and low-fat (LFD) diets, distinguishing between “healthy” patterns (emphasizing plant-based foods, whole grains, and unsaturated fats) and “unhealthy” patterns (higher in refined carbohydrates, animal fats, and processed foods). The findings showed that quality—not just macronutrient quantity—was critical.
Healthy versions of both LCD and LFD patterns were associated with significantly lower CHD risk. In contrast, unhealthy versions of both diets were linked to higher risk. For example, a healthy low-carbohydrate diet was associated with a 15% lower CHD risk, while an unhealthy low-carbohydrate diet was associated with a 14% higher risk. Similar patterns were observed for low-fat diets.
Blood biomarker analyses showed additional differences: healthier versions of both dietary patterns were associated with higher HDL (“good”) cholesterol, lower triglycerides, reduced inflammation, and favorable metabolomic profiles. Unhealthy versions showed the opposite pattern.
The findings challenge the idea that simply reducing carbohydrates or fat is inherently heart-protective. Overall, the authors suggest that whether a diet is low in carbs or fat matters less than the quality of the foods chosen within that pattern.
REFERENCES
Wu, Z., Liu, B., Wang, X., Alessa, H., Zeleznik, O. A., Eliassen, A. H., Clish, C., Wang, M., Mukamal, K. J., Rimm, E. B., Hu, Y., Hu, F. B., & Sun, Q. (2026). Effect of low-carbohydrate and low-fat diets on metabolomic indices and coronary heart disease in U.S. individuals. Journal of the American College of Cardiology, Advance online publication. https://doi.org/10.1016/j.jacc.2025.12.038 (American College of Cardiology)
Brownstein, M. (2026, February 11). Low-carb and low-fat diets associated with lower heart disease risk if rich in high-quality, plant-based foods, low in animal products. Harvard T.H. Chan School of Public Health. https://hsph.harvard.edu/news/low-carb-and-low-fat-diets-associated-with-lower-heart-disease-risk-if-rich-in-high-quality-plant-based-foods-low-in-animal-products/ (hsph.harvard.edu)
