People at higher risk of heart disease may gain the most from reducing saturated fat in their diets, a new review finds.
The analysis, published Dec. 16 in Annals of Internal Medicine, examined more than a dozen clinical trials involving over 66,000 participants. Researchers found that cutting saturated fat helped those with a greater likelihood of heart problems avoid heart attacks and strokes. For people without these risk factors, the benefits were less clear over a five-year period.
Saturated fat is commonly found in foods like butter, steak, pizza, ice cream, and many processed meats.
“Our results provide a small but important piece of evidence used in updating the Dietary Guidelines for Americans,” said study co-author Bradley Johnston, associate professor of nutrition at Texas A&M University in College Station, Texas.
Experts say reducing saturated fat remains one of the most effective ways to prevent high cholesterol.
Alice Lichtenstein, director of the Cardiovascular Nutrition Laboratory at Tufts University in Boston, who was not involved in the study, emphasized the value of prevention. “You can’t measure something that hasn’t developed yet in people who don’t have disease,” she said. “But the whole idea is to prevent it.”
The review also highlighted the importance of what replaces saturated fat in the diet. Swapping it for polyunsaturated fats—found in foods like fatty fish or canola oil—helped lower “bad” LDL cholesterol and reduced the risk of heart disease.
Current federal dietary guidelines recommend keeping saturated fat to less than 10% of daily calories. The American Heart Association suggests an even lower limit of under 6%.
Efforts to reduce saturated fat began in the 1960s and have influenced food choices for decades. However, not all foods high in saturated fat have the same effects. Processed meats, for example, also contain sodium, which can raise blood pressure, while some dairy products, such as milk and yogurt, may support better blood sugar control and weight management.
Lichtenstein cautioned against relying on a single study to drive nutrition policy. “One systematic review shouldn’t have a major effect on policy without a broader body of evidence,” she said.
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