Food Quality Tracked With Heart Risk More Than Low-Carb or Low-Fat Labels

CATEGORY: EATING FOR HEART HEALTH

The label on a diet mattered less than what was actually on the plate. In an analysis of nearly 200,000 U.S. adults, the healthier versions of both low-carbohydrate and low-fat eating, the versions built around plant-based foods and whole grains, were linked to lower risk of coronary heart disease. The less healthy versions of those same two patterns were linked to higher risk. Nobody was handed a diet here. People reported what they usually ate, which makes this an association rather than cause and effect.¹

Three Decades of Food Questionnaires, 20,033 Cases

The researchers pooled three long-running cohorts: the Nurses’ Health Study, its sequel, and the Health Professionals Follow-Up Study. That came to 198,473 adults followed for up to about three decades. Every few years participants filled out detailed questionnaires about what they ate. Those answers let the team score how closely each person’s diet matched several versions of low-carbohydrate and low-fat eating. The versions were graded by quality. Some emphasized plant-based foods and whole grains; others leaned on animal products and refined carbohydrates. The team then counted new cases of coronary heart disease, the narrowing of the arteries that supply the heart, and logged 20,033 of them. Blood samples were checked against the dietary patterns as well.

15% Lower One Way, 14% Higher the Other

Set against people whose diets least resembled each pattern, those following a healthy, plant-forward low-carbohydrate diet most closely came in about 15% lower for coronary heart disease. The healthy low-fat version came in around 13% lower. Then the picture flips. Diets high in animal products and refined carbohydrates carried roughly 14% higher risk within the low-carbohydrate group and about 12% higher within the low-fat group.¹ Scored without regard to food quality, the overall low-carbohydrate pattern went with slightly higher heart disease risk and the overall low-fat pattern with slightly lower.¹

Triglycerides, HDL and C-Reactive Protein Moved With the Pattern

The healthier patterns came with a friendlier blood profile: lower triglycerides, a type of fat in the blood, higher HDL or “good” cholesterol, and lower levels of C-reactive protein, a marker of inflammation. The less healthy patterns showed the reverse. Those blood signals give the finding a plausible route from plate to artery. Participants were mostly health professionals, which limits how far the numbers travel. The same quality split does appear elsewhere. A 2026 review pooled 19 long-term studies of 846,589 people. Diets closest to a healthful plant-based pattern, built on whole grains, vegetables, fruit, nuts and legumes, were linked to about 23% lower risk of coronary heart disease. Plant-based patterns leaning on refined grains, sweets and sugary drinks were linked to about 24% higher risk.²

Key Takeaways

• Among nearly 200,000 adults, the quality of a low-carbohydrate or low-fat diet tracked with heart disease risk more closely than the diet type did.
• Versions rich in plant-based foods and whole grains went with lower risk; versions high in animal products and refined carbohydrates went with higher risk.
• The healthier patterns also tracked with better cholesterol, triglyceride and inflammation markers in the blood.

References

1. Wu Z, Liu B, Wang X, et al. 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. 2026;87(20):2764–2781. link
2. Kim Y, Kim Y. A plant-based diet and cardiovascular disease, coronary heart disease, and stroke: a systematic review and meta-analysis of prospective cohort studies. Nutrients. 2026;18(17):2779. link.