While there are still some who resist the notion that more fat in the diet can be healthy, the general consensus that high quality fats and oils can be a major constituent continues to grow. Whether someone is getting 40% of their energy from fats or 60% would be less important in my opinion. The greatest issues with fats are more about their qualities and stability overall.
The human body places the majority of the fats it receives in cell or organelle membranes (such as the mitochondrial membrane). The ability of these fats to stay cool under pressure and to avoid becoming free radicals with exposure to the oxidative stress that is often present is essential for long-term health. Highly polyunsaturated fatty acid (PUFA) levels from seed oils contain multiple sites that can react with oxidation-driving molecules, creating much greater potential for generating cellular damage in one area or another. While these polyunsaturated oils are needed in small quantities every day, excessive amounts (as found in the typical American diet and in most processed foods) create greater risk for multiple diseases.
The best sources of polyunsaturated fat are organic ground flax, organic cold pressed flax oil, pumpkin seeds, unrefined krill oil, and small oily wild fish. All of these choices contain some major upsides in spite of being rich sources of polyunsaturated fat. First, they have solid levels of omega 3 fatty acids. Only pumpkin seeds are lower in this area, but pumpkin seeds are an incredible source of magnesium, zinc, and other nutrients. Unlike other PUFA-rich foods, organic flax and oily fish are low in their omega 6 fatty acid content. This means that they are less likely to drive inflammation on their own and may offer some anti-inflammatory protection.
As with most of the foods we are discussing, organic, cold pressed is critical. Conventionally grown flax will have significant levels of glyphosate in it and non-cold pressed will probably have been exposed to the petroleum distillate/solvent hexane for removal from the seed. Fish like sardines and mackerel are much lower on the food chain and make the most sustainable, as well as cleanest choices from the ocean.
Collectively, these sources of polyunsaturated fat should make up the minority of the fat in our diet. Again, some research suggests no more than 5% our calories and others indicate that they may be well tolerated at levels closer to 10%. Those differences are probably based upon numerous other factors, but choosing them wisely and from the best possible sources is equally important.
Monounsaturated fatty acids (MUFAs) have a dramatically lower susceptibility to oxidation than the aforementioned PUFAs. In addition, they are close to being physiologically neutral to the process of inflammation. Because they are not omega 3 or omega 6-rich, most foods high in their MUFA content do not favor pro-inflammation or anti-inflammation pathways. The most monounsaturated fats and oils are extra virgin olive oil, almonds, and avocadoes. All of these have at least a small amount of PUFAs, but it is a small minority of that fat that they offer. It is best to buy organic, raw almonds whenever possible. It is also important to do what you can to assure that your olive oil is truly extra virgin olive oil and not part of some lower quality blend. Sourcing olive oil from one estate or smaller olive farm is the best way to assure this. Try to make monounsaturated fats a bigger part of your day by using olive oil for lower heat cooking (less than 300F) or for salad dressings and dips. Snack on almonds and guacamole whenever the opportunity arises. These fats are stable and populations that have consumed as high as half their calories from olive oil (the Cretans and Ikarians for instance) have amazing health.
Lastly, and this is one that some still need to hear repeatedly, are the saturated fats. Believe it or not, saturated fats are the type that our cell membranes do the best with overall. Of course we do need the other types in varying amounts, but the majority of the fatty acids in these vulnerable membranes have got to be stable and less prone to oxidation. This is where coconut, extra virgin coconut oil, grass-fed butter, and macadamia nuts come in. All of these are almost entirely comprised of saturated fat.
Pacific Islanders and Sri Lankans have incredibly low risks for heart disease and cancer when they follow their traditional diets made up largely of coconut oil and fat. These fats also hold up to cooking and higher temperatures better than other types of fats. They make the best fats as foundations for healthy diets. Of course olive oil can too, so long as we are not cooking with it in high heat applications.
Lard could make this list if it were both organic and from 100% grass or pasture-raised animals. But because there is such a limited supply of products that meet these criteria, it is unlikely that most will find this. A non pasture-raised lard is not a recommendation that I will make.
So, in summary, choose more saturated fats for most of your cooking and don’t be afraid of butter! Be sure to also include higher quality, extra virgin olive oil whenever possible. Make the PUFA-rich oils a smaller part of your diet by limiting them to what you get from organic flax seeds or oil and smaller, oily, ocean going fish. If we do this, we provide our physiology with a more durable, longer lasting architecture that will also be less flammable when it comes to inflammation.