Much of the confusion happens when people make generalizations about fat in the diet. Many diet books, media outlets and blogs talk about fats as though they were all the same. In reality, dozens of fats are common in the diet, and each one has a different role in the body and effects on your health. Even within groups of fats like saturated, unsaturated and polyunsaturated, specific fats still have different roles. The key is to understand that each type of fat has its own unique effects on the body. Once you start thinking about fats more specifically, you’ll be better equipped to make healthy dietary choices.Dietary cholesterol does not change the risk of heart disease for most people, according to the largest studies available. However, for up to a quarter of the population, high dietary cholesterol increases “bad” LDL and “good” HDL cholesterol.
While people who give dietary advice often lump saturated fats together, there are many different kinds of saturated fats that have different effects on health. Labeling all saturated fats as “healthy” or “unhealthy” is an oversimplification. One discriminating feature of fats is their length, meaning the number of carbon atoms they contain. Fats may be short (containing fewer than six carbons), medium (6–10 carbons), long (12–22 carbons) or very long (22 or more). Your cells treat fats very differently depending on their chain length, which means fats of different lengths can have different effects on health. Even-length saturated fats include stearate, found primarily in meat, cheese and baked goods. They also include palmitate, which is named for palm oil, but also found in dairy, meat, cocoa butter and fully hydrogenated vegetable oils. Another even length saturated fat, myristate, can be found in butter, coconut and palm oil. Odd-length saturated fats, including heptadecanoate and pentadecanoate, come mostly from beef and dairy. Because the health effects of saturated fats and the ways they are metabolized are so nuanced, it is not useful to think of them as collectively “good” or “bad.”
Though these differences are nuanced, the takeaway is that the specific food is more important than the type of fat it contains. For example, an avocado contains the same amount of saturated fat as three slices of bacon. Bacon increases the levels of “bad” LDL cholesterol. However, eating about a half to 1.5 avocados daily actually reduces levels of “bad” LDL cholesterol, according to a study of 229 adults. Some saturated fats contribute to heart disease. However, calling all saturated fats bad is an oversimplification. In fact, when they come from dairy and vegetable sources, as well as certain meats, some saturated fats are healthy.