The fats we eat are not only used as a reserve energy source and burned for fuel, they are also used to build structures in our bodies, such as cell membranes. It is important that we get the types of fats our bodies need to build those structures, and to understand the distinction between the natural fats our bodies expect and the unnatural fats so often provided in the processed foods we eat.
Processed vs. Unprocessed
The distinction between processed foods and unprocessed foods applies to fats. Some of the fats in our food supply come from natural, unprocessed or minimally processed sources and some from very unnatural processed sources. Processed fats and oils can lead to inflammation.
Animal fats are natural, provided they haven’t been hydrogenated. If purchasing lard, beef tallow, butter, or other animal fats check the label to ensure that they haven’t been hydrogenated.
Fats from plants can be natural or unnatural depending on how they are produced: refined vs. unrefined. Natural oils are extracted without using chemicals or heat. Unhealthy processed oils are produced with heat and/or chemicals. Unfortunately, the overwhelming majority of fats in processed foods and used for cooking in restaurants is the unhealthy processed kind.
Some vegetable oils come from the fruit of the plant: olive, palm, coconut; and others from the seeds: soybean, peanut, corn, safflower, grapeseed, canola (from the rapeseed plant), etc.
Natural oils are produced without heat and chemicals, and will say something like “cold pressed,” “expeller expressed,” or “unrefined” on the label. Natural, healthy, olive oil will be labeled “extra virgin” (“regular” olive oil is extracted using heat and/or chemicals).
Most seed oils are created using an industrial process involving heat and solvents to extract the oil (the solvent generally used is hexane, a petroleum product; before processing is complete the hexane is evaporated away).
Check food labels carefully. Vegetable oils found in processed foods (soybean oil, peanut oil, corn oil, canola oil, grape seed oil, etc.) are almost always the industrially produced kind.
To sum up processed vs. unprocessed fats:
Animal fats (lard, beef tallow, duck fat, butter) are natural if they haven’t been hydrogenated or otherwise processed.
Vegetable oils from the fruit of the plant (olive, palm, coconut, avocado) are natural if they are unrefined.
Vegetable oils from seeds (soybean, peanut, corn, grape seed, canola, safflower) are unnatural and inflammatory unless they are cold pressed (and most aren’t). A major problem with processed oils is that they are very prone to oxidation, especially when heated. The fry vat in a typical restaurant is reheated over and over. Anything cooked in it will be heavily oxidized and inflammatory.
And note that margarine is made from these unnatural oils, and is often hydrogenated to boot.
Be sure to check food labels carefully for these oils. The food industry puts them in just about everything.
Types of Fats
The three types of dietary fat are saturated, monounsaturated, and polyunsaturated. “Saturated” means all the carbon atoms in the fatty acid molecule have a hydrogen molecule bound to them, and so there is no gap where other atoms can interact with it. “Monounsaturated” means the fat molecule has one gap where other atoms can interact with it. “Polyunsaturated” means that the fat molecule has at least two gaps where other atoms can interact with it. Saturated fats are less prone to oxidation because they don’t have that gap; polyunsaturated fats are most prone to oxidation because they have multiple gaps.
In choosing how much of which types of fats to include in our diets, it is important to know how the different kinds of fats can affect our health. Monounsaturated fat (MUFA): Olive oil contains primarily MUFA, in the form of oleic acid. Some meats contain significant amounts as well (half of the fat in a ribeye steak is oleic acid). Oleic acid is not considered detrimental to health.
Polyunsaturated fat (PUFA): An important distinction between types of PUFA is between omega-3 fats and omega-6 fats. Both are essential fatty acids (meaning our bodies need them, can’t make them, and so must get them from our food).
Most of us get too much omega-6 and too little omega-3 fats. Pre-industrial populations tended to have rates of 4:1 or lower; Americans tend to have an omega-6/omega-3 ratio of around 16:1
A high ratio is associated with inflammation and heart disease risk.
Natural sources of Omega-6 PUFA include walnuts, sunflower seeds, avocado, eggs, and cashews. It is far better to get our omega-6 PUFA from those real food sources than from the unnatural oils found in processed foods. (The average American gets 10 percent of calories from soybean oil, a processed oil very high in omega-6 fats.)
As to omega-3, according to Healthline, some health organizations recommend a minimum of 250–500 mg each day for healthy adults. This can be obtained from about 8 ounces of fatty fish per week. Wild-caught cold-water fish like salmon are the best sources. Eggs (especially pastured eggs) have significant omega-3 fats as well; but they aren’t as good a source as fish.
Fish oil supplements are available for those wishing to increase their omega-3 intake. Choose a high-quality supplier to ensure the fats aren’t oxidized. Also, don’t take more than the recommended dose.
If we get our required PUFA from real foods rather than from the industrial oils found in processed foods, it will be less likely to cause inflammation and contribute to chronic disease.
Saturated fat: There is much controversy around saturated fat and its effect on our health. For many years the dietary guidelines have recommended sharp limits on saturated fat in the diet (though those recommendations no longer include a limit on overall fat or dietary cholesterol). But there are many researchers who do not believe the evidence against saturated fat is conclusive. In fact, the Journal of the American College of Cardiology published a review by top researchers that concluded that there was not sufficient evidence to support the recommendation to limit saturated fat. Other researchers dispute those findings. So far no large, randomized controlled trials have confirmed the hypothesis that saturated fats will shorten our lives. There are a number of large observational studies that show a small association between saturated fat and heart disease mortality, but those studies cannot prove causation.