Why Do They Matter?

A primary focus of the bioenergetic theory of health is preventing any blocks in cellular energy creation, so that the body's cells don't need to revert to backup energy creation pathways, and the body is consistently operating with an energy surplus. Polyunsaturated fat can directly block the effective creation of cellular energy. Avoiding the polyunsaturated fatty acids (PUFA) is one of the primary goals of a bioenergetic diet.

The Chemistry Of Fat

Fats are molecules made up mostly of carbon and hydrogen atoms. In some fats, there are enough hydrogen atoms in the molecule that every carbon atom is attached with only one "bond". Those fats are referred to as saturated fats, meaning they are saturated with hydrogen atoms. In fats with fewer hydrogen atoms, some carbon atoms are attached with two bonds. If there is only one of these double bonds, the fat is monounsaturated. If there is more than one, the fat is polyunsaturated.

This is important to our health because of oxidation. When a molecule oxidizes, its molecular structure changes. Saturated and monounsaturated fats are very resistant to oxidation, but PUFA readily oxidize, both before we eat them and in our bodies. When PUFA oxidize, the molecules they change into can cause severe damage.

What Does This Mean For Our Health?

Fats are used for structure within the body, including within the cells themselves. Within the cell, oxidized fat molecules can block the primary pathway the cell would normally use to create energy. Cells with enough oxidized fat in their structure can't use glucose properly, and must revert to backup pathways to create energy, lowering energy output. If too many cells are "infected" with oxidized fat, a person will develop metabolic dysfunction due to the lack of ability of these cells to effectively process glucose.

Oxidation of PUFA within the body might also lead directly to other diseases. Some PUFA can oxidize into molecules that are known to be very damaging in the body. Some of these substances are directly implicated in diseases including atherosclerosis, dementia, auto-immune diseases, fatty liver disease, fybromyalgia, asthma, and macular degeneration. This is in addition to the many chronic disease states that are caused by the energy shortage these fats can lead to in the cells.

Sources Of PUFA

PUFA are found mostly in non-tropical nuts and seeds, and the fat of cold-blooded animals. One of the features of PUFA is that they stay liquid at lower temperatures. This is advantageous for both plants and cold-blooded animals that need to survive in cold weather. Most warm-blooded animals, including humans, do not make PUFA. The only PUFA in these animals come from their food.

The most concentrated sources that are typically eaten by humans (and farm-raised animals) are seed oils, which are the concentrated fats from high-PUFA seeds. This includes most common present-day cooking oils including corn, peanut, canola (rapeseed), sunflower, safflower, rice bran, grape seed and sesame seed oils. Tropical nut oils, particularly coconut oil, palm kernel oil, macadamia nut oil and cocoa butter, are low in PUFA.

Olive oil, palm oil and avocado oil have some PUFA, but are mostly monounsaturated fat. Pure versions might be fine in moderation, but many of these oils are impure, either because their seeds were included in the extraction process, or because the oil is diluted with a higher-PUFA seed oil, or both.

Another source of PUFA in most Western diets is farmed chicken and pork fat. Non-ruminant animals like chickens and pigs have digestive systems that do not transform PUFA into saturated or monounsaturated fat. Therefore, when those animals are fed high-PUFA diets, their fat is also high in PUFA. In present-day farming, seed-oil-laden feed is ubiquitous, so the PUFA content of any farmed chicken or pork fat (including bacon and chicken eggs) is high.

How Much Do We Eat?

The typical evolutionary human diet probably included around 1% to 2% of calories from PUFA. Our bodies have many anti-oxidants, and evolved to deal with small amounts of oxidation from these quantities of PUFA. However, as a person consumes more and more PUFA, that system can become overwhelmed.

With the invention of cheap food-grade seed oils in the 1800s, and their continued increase in use particularly since the 1970s, the amount of PUFA that most people consume has exploded. Not coincidentally, chronic diseases and obesity have also exploded during that time. Some studies estimate that the modern Western diet can include up to 25% of calories from PUFA, primarily from seed oils.

Avoiding PUFA in our current food environment can be difficult, but there are vast potential health benefits to making the effort, and there is a wide variety of great food available without the dangers of PUFA.