saturated fat

Saturated fat refers to a class of fatty acids in which carbon atoms are fully 'saturated' with hydrogen atoms, meaning they contain no double bonds in their chemical structure. This molecular configuration makes these fats solid at room temperature, distinguishing them from unsaturated fats, which remain liquid. Saturated fatty acids (SFAs) are found in animal fats such as butter, lard, high‑fat dairy products, red meat, and certain tropical plant oils like coconut and palm kernel oil. Unlike essential fatty acids such as omega‑3s and omega‑6s, saturated fats are not considered essential because the human body can synthesize them endogenously. Historically, saturated fats have been a central focus of nutrition science because of their influence on blood lipid profiles, particularly low‑density lipoprotein (LDL) cholesterol, a well‑established risk factor for atherosclerotic cardiovascular disease. The Dietary Guidelines for Americans and major heart health organizations recommend limiting saturated fat intake to less than 10% of total energy intake, with some organizations such as the American Heart Association advocating for an even stricter limit of 5–6% to reduce cardiovascular risk. Although saturated fats provide caloric energy and play roles in food texture and flavor, their health impact largely depends on the overall dietary pattern and what nutrients replace them when reduced in the diet.

Saturated fat contributes to several physiological functions, although it does not have an established recommended dietary allowance as with essential nutrients. The primary biological role of all fats, including saturated fats, is to provide a dense source of energy; each gram supplies approximately nine calories, more than twice the energy provided by carbohydrates or proteins. Saturated fats also facilitate the absorption of fat‑soluble vitamins—A, D, E, and K—because dietary lipids help form micelles in the gut necessary for transporting these vitamins across the intestinal wall. Structurally, saturated fatty acids are components of triglycerides and phospholipids, which are integral to cell membranes and intracellular signaling pathways. In the context of lipid metabolism, saturated fat intake influences serum lipoprotein concentrations. Numerous studies have demonstrated that higher intakes of saturated fats raise LDL cholesterol levels, which in turn are associated with atherosclerotic plaque formation and increased risk for coronary heart disease and stroke. Evidence from systematic reviews and meta‑analyses indicates that reducing saturated fat intake likely lowers the incidence of combined cardiovascular events, though effects on total mortality are less clear. The umbrella review published in 2024 reported that a reduction in saturated fat intake was associated with a relative risk reduction in combined cardiovascular events but had minimal impact on all‑cause or cardiovascular mortality. These effects are thought to be mediated through improvements in serum LDL cholesterol and potentially other cardiometabolic risk markers. Importantly, the health impact of saturated fats can vary by food source. For example, saturated fats in whole‑fat dairy products appear to have a different association with cardiometabolic outcomes compared with those in processed meats, possibly due to the food matrix and accompanying nutrients. Overall, the consensus among public health bodies remains that replacing saturated fats with unsaturated fats—especially polyunsaturated fats—consistently yields better outcomes for cardiovascular health. Energy balance and total diet quality are critical contexts when considering the role of saturated fats in health.

Unlike vitamins and minerals, saturated fat lacks an established Recommended Dietary Allowance because it is not essential for survival; the human body can produce saturated fatty acids endogenously. Consequently, dietary guidance focuses on limiting intake rather than meeting a minimum requirement. Both the Dietary Guidelines for Americans and the Food and Nutrition Board advocate that saturated fat should account for less than 10% of total daily calories. For an adult consuming a 2,000‑calorie diet, this translates to fewer than 20 grams of saturated fat per day. The American Heart Association suggests a stricter limit of 5% to 6% of calories from saturated fats, which equates to about 11–13 grams per day on a 2,000‑calorie diet, based on evidence linking lower saturated fat intake with improved LDL cholesterol profiles. These population‑based recommendations apply across age groups starting from age 2 years, with no special profile for infants or young children, because saturated fats are not required to prevent deficiency. Factors influencing individual needs include total energy requirements, activity level, and the proportion of other macronutrients in the diet. Importantly, guidance emphasizes the quality of fats consumed; replacing calories from saturated fats with equivalent calories from polyunsaturated or monounsaturated fats is associated with better cardiovascular outcomes. For people with elevated LDL cholesterol or established cardiovascular disease, clinicians often recommend tighter limits and tailored dietary plans. In clinical practice, the concept of Acceptable Macronutrient Distribution Range (AMDR) for total fat—25% to 35% of daily calories—remains relevant, but within that, saturated fats should be a relatively small fraction, with the majority of fat intake coming from unsaturated sources.