Reducing saturated fat intake may lower the risk of death and major cardiovascular events, but the benefit appears limited to people already at high cardiovascular risk, according to a new review published in Annals of Internal Medicine.
The systematic review analyzed data from 17 randomized trials involving more than 66,000 participants and examined how reducing or modifying saturated fat intake affected cholesterol levels, mortality and cardiovascular outcomes over at least two years. Researchers found that while cutting saturated fat consistently lowered total and LDL cholesterol, meaningful reductions in deaths and heart-related events were seen primarily among people with high baseline cardiovascular risk.
For individuals at low to intermediate risk, reducing or replacing saturated fat offered little or no measurable benefit over a five-year period.
The review also highlighted an important distinction in how dietary fat changes were made. The strongest evidence for reducing nonfatal heart attacks emerged when saturated fats were replaced with polyunsaturated fats, rather than simply removed from the diet. Replacing saturated fat with polyunsaturated fat was associated with larger absolute reductions in heart attack risk among high-risk participants.
Across the trials, reductions in cholesterol were observed regardless of participants’ baseline risk. However, those improvements did not consistently translate into lower rates of death or cardiovascular events for people without existing risk factors, underscoring that cholesterol changes alone do not guarantee better long-term outcomes.
The authors noted that dietary advice around saturated fat may be most relevant for people with established cardiovascular disease or multiple risk factors, such as high blood pressure, diabetes or a history of heart attack or stroke. In these groups, both reducing saturated fat and paying attention to what replaces it appeared to matter.
The findings also help explain why population-wide recommendations to reduce saturated fat have produced mixed results in previous research. When baseline risk is low, the absolute benefit of dietary fat changes may be small and difficult to detect over shorter time frames.
The authors emphasized that the results do not suggest saturated fat intake is irrelevant, nor do they support a one-size-fits-all approach. Instead, the data point toward a more targeted strategy that considers individual risk and focuses on improving overall fat quality, rather than simply lowering total fat intake.
An accompanying editorial noted that these findings reinforce the importance of replacement foods, not just reduction. In typical diets, saturated fats often come from foods such as butter, cheese, whole-fat dairy products, fatty cuts of red meat and processed foods made with animal fats or tropical oils.
Polyunsaturated fats, by contrast, are commonly found in foods like vegetable oils, nuts, seeds and certain spreads made from plant oils. The review suggests that for people at high cardiovascular risk, replacing saturated fat–rich foods with sources of polyunsaturated fat may matter more than simply cutting fat overall.
To keep expectations realistic, the authors emphasized that benefits were not observed uniformly across all populations and depended on both baseline cardiovascular risk and the specific nutrients replacing saturated fat.
Because the review focused on randomized trials, the authors cautioned that results should be interpreted in the context of study design, duration and participant characteristics. Longer-term effects in lower-risk populations remain uncertain.
The authors reported no primary funding source for this study.