Fatty Acids, Their Food Sources, and Cardiovascular Disease: Current Evidence and Controversies Surrounding the 2025-2030 Dietary Guidelines for Americans.

The 2025-2030 Dietary Guidelines for Americans affirm the recommendation of limiting SFA intake to within 10% of total energy intake but simultaneously recommend the intake of red meat and full-fat dairy rich in SFA, leading to public confusion. This review summarizes evidence from short-term feeding trials, longitudinal observational studies, and long-term dietary interventions that examined SFA, in comparison with other fatty acids and carbohydrates, in relation to blood lipids and coronary artery disease (CAD) risk. Overall, the knowledge base clearly suggests that SFA, when isocalorically replacing cis MUFA and cis PUFA, leads to elevated levels of atherogenic low-density lipoprotein cholesterol. Consistently, longitudinal observational studies and long-term high-quality dietary intervention trials demonstrated that isocalorically replacing SFA with PUFA led to a lower risk of developing CAD. Conversely, when SFAs are replaced by refined carbohydrates, the effects on blood lipids and CAD risk become more neutral. Evidence from feeding trials and observational studies also suggests that animal fat, including dairy fat, leads to adverse lipid profiles and elevated CAD risk when compared with nontropical plant-based oils rich in MUFA and PUFA. A higher consumption of red and processed meats is also associated with a higher CAD risk, especially when compared with nuts, legumes, and whole grains. The health impact of dairy products may be influenced by their fat content, vary among dairy products, and depend on the consumption levels. Overall, the evidence supports the conclusion that a heart-healthy diet should emphasize healthful sources of PUFA and MUFA, such as nontropical plant oils, nuts, and seeds; healthful sources of carbohydrate and protein, such as fresh fruits and vegetables, whole grains, legumes, and dark-meat fish; and moderate intake of low-fat and fermented dairy products, while deemphasizing excess intake of red and processed meats and full-fat dairy products.