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Fats: The Macronutrient Guide

By Tyler Woodward

In this article, we will talk about everything you need to know about the essential macronutrient fat.

Key Takeaways: 

  • What is fat and why is it necessary in our diet?
  • The difference between healthy and unhealthy fats and the chemistry behind it 
  • How to identify and eat healthy fats

Table Of Contents:

What is Fat

What Is Fat?:

Fats are an essential macronutrient in our body, meaning that we cannot survive without it for a prolonged period of time. Fats are actually a type of lipid. All lipids have one key quality that they are insoluble or do not dissolve in water. Not all lipids are fats, but all fats are a type of lipid. Fat is the most calorically-dense of the three macronutrients containing 9 calories per gram compared to 4 calories per gram with carbohydrates and proteins. 


When we refer to fat in its dietary form, we are typically referring to it as a triglyceride. In triglycerides, there is one glycerol molecule that attaches to three (tri) individual fatty acid tails. These fatty acid tails are what we will be focusing on when discussing the fats that we regularly consume in our diets. Fatty acid tails consist of a chain of bonded carbon atoms. Every carbon atom has four open “spots” that can bond to another molecule. In these fatty acids, the carbon molecules will form either a single bond or a double bond to another carbon molecule and will fill the remaining spots with hydrogen bonds. 

Types of Fat

Types Of Fats:

When referring to fats, there are four types of fats that are commonly found in our modern diets:

  • Saturated Fats
    • Saturated Fats (or fatty acids) do not contain any double bonds, so each carbon molecule will be bonded to a carbon molecule on either side and two hydrogen molecules. Saturated fats are solid at room temperature.
  • Monounsaturated Fats
    • Monounsaturated fats contain one double bond in which two carbon molecules in the fatty acid chain are double bonded to each other. These double bonded carbon molecules will only attach to a single hydrogen molecule each. Monounsaturated fats are generally, but not always, liquid at room temperature.
  • Polyunsaturated Fats
    • Polyunsaturated fats contain at least two carbon-carbon double bonds in their fatty acid chain. Polyunsaturated fats are always liquid at room temperature.
  • Trans Fat
    • Trans fat can either be a monounsaturated fat if they contain only one carbon-carbon double bond or a polyunsaturated fat if it contains multiple carbon-carbon double bonds. Trans fat differs from monounsaturated and polyunsaturated fats in that the position their double bond occurs in is much less stable, but I’ll get to this in a bit. Trans fat can be liquid or solid at room temperature depending on if they are monounsaturated or polyunsaturated. 

Periodic Table of Elements

Organic Chemistry 101:

To truly understand the properties of these fatty acids, you must understand the chemistry behind them. Although organic chemistry is viewed as a daunting subject for most, including myself, I am going to simplify it as much as possible. 

Imagine atoms like pieces of a puzzle, some puzzle pieces only have one open spot to connect to another piece, while others have 2, 3, 4, ect. Just like in a puzzle, the “goal” of the atom is to fill their open spots, and the more open spots that they are able to fill, the more stable they become. Unlike in a puzzle, there are multiple ways for an atom to fill these open spots, some of which are more stable than others. These open “spots” are what we refer to as valence electrons. These electrons form rings around the nucleus or the center of the atom. 

The periodic table of elements is organized around this principle; the first row only has 2 valence electrons, or 2 spots, the second row has 8 valence electrons, and the third row contains 18 valence electrons. As you move from left to right across the periodic table, the atoms become more stable, as they naturally exist with more filled spots so to speak. Once an element has filled all of its spots, it becomes significantly more stable and less reactive with other elements/ compounds. The elements all the way to the right are known as the inert gases and naturally exist with all of their spots filled and do not react with the other elements. 

Organic chemistry focuses on the pivotal element of life, carbon. Carbon lies right in the middle of the periodic table with 4 valence electrons, meaning it has 4 potential spots to fill. As you can imagine, there are an almost infinite number of ways carbon can bond with other elements to fill these four spots. Typically, the easiest way to do so is by bonding with hydrogen atoms, as hydrogen is the most abundant element in the universe. Carbon also commonly bonds with itself forming single, double or triple bonds filling 1, 2, or 3 spots respectively (carbon cannot form a quadruple bond with itself, but that is a whole other story). Single bonds between atoms are the most stable bond because they allow for the individual atoms to freely rotate among themselves.

Double bonds restrict this rotation, holding the atoms in place, which is less stable in that they are easier to break apart. Triple bonds restrict the movement even more, meaning that they are the least stable and easiest to break apart. 

If these double bonds are less stable, then why do we find them naturally occurring in unsaturated fats?

The restricted movement in these double bonds actually has one huge benefit in nature. Restricting the movement between these atoms limits the transfer of energy & heat between them, meaning they act as insulators. These double bonds in the unsaturated fats are necessary for the survival of plants and animals that live in cold-weather climates. Without these unsaturated fats, they would freeze. There is a trend seen in nature that the colder the climate, the more unsaturated fats are found in the plants and animals that live there. This is why cold-weather fish like salmon, tuna, and herring are generally rich with omega-3 and omega-6 polyunsaturated fatty acids. 

Trans Fats

What About Trans Fat?

You know that one person that decides to squeeze in on a 3-person couch instead of sitting in the wide-open chair right next to them? That is basically the real-life equivalent of trans fat. When two carbon atoms make a double bond, there are two conformations or positions in which the double bond can occur. One position is much more favorable than the other because it provides more space and therefore allows more movement between the atoms, this is known as the cis-conformation (sitting in the chair instead of squeezing on the couch). Then there is the trans-conformation, which is still possible, but it is a much tighter squeeze, making it much less energetically favorable and a lot less stable. Due to this decreased stability, trans fats are not commonly found in nature and if they do occur, it is in very small portions. 

So let’s rank these fatty acids in order of stability from least to most stable...

Trans Fat (mono or polyunsaturated) -> Polyunsaturated Fats -> Monounsaturated fats ->Saturated fats

The stability of these fatty acids also coincides with the temperature at which these fatty acids become liquid. The more saturated the fat is the more stable the fat will be at higher temperatures. You can actually see this in real-time with coconut oil. Coconut oil contains ~95% saturated fats and can be left at room temperature for over a year without going rancid. Polyunsaturated fats like those found in fish, must be constantly cooled or will go rancid within a number of hours. This can be easily detected by the rotten, fishy smell often associated with fish and fish markets.  

Are Certain Fats Healthier Than Others

Are Certain Fats Healthier Than Others?

Yes, as warm-blooded mammals, we want to consume foods that are stable at our internal body temperature of ~99°F. When we consume trans fat, polyunsaturated fats, and certain types of monounsaturated fats, their double bonds will be oxidized or broken down and will release free radicals into the body. Free radicals are associated with causing stress, inflammation, DNA damage, among a plethora of other consequences down the line1. There has also been shown to be a consistent negative correlation with the amount of polyunsaturated fats consumed in mammals and shorter lifespans, meaning animals that favor less saturated fats tend to have shorter lifespans. 

Does fat make you fat?


Does Fat Make You Fat?:

Fat does not make you fat and neither do carbs or protein. What causes weight or fat gain is the consumption of excess energy and an inability to utilize that energy as fuel. Carbs, fats, proteins, and alcohol all contain a number of calories per gram consumed. 

*Remember calories are just a measurement of energy*

Carbs and protein have 4 calories per gram, alcohol has 7 calories per gram, and fat has 9 calories per gram. As long as you consume around the same amount of calories that you burn on a daily basis, you will not gain weight/fat no matter which macronutrient the calories come from. 

I think it is also worth noting that not all food sources are created equal. It is more difficult for the human body to digest certain foods like wheat or polyunsaturated fats which in turn forces the body to redirect its attention and energy from growth & repair to healing itself and reducing inflammation. 

Diets, Fat Loss & Fatty Acid Metabolism

Diets, Fat Loss & Fatty Acid Metabolism:

Fats, just like all the food we eat, can be broken down in the body to be used for energy. For a number of reasons, your body preferentially uses its carbohydrates stores as fuel, as long as it has adequate carbohydrates to use. The key to losing weight or fat is  to put your body into a caloric deficit by consuming fewer calories than you burn on a daily basis, which forces your body to pull from its fat reserves to compensate for this lack of energy. 

Are Any Diets Better Than Others For Fat Loss?

Yes and no. As long as you consume fewer calories than you burn, you will lose weight over time, no matter the diet you choose to do so with. Although there is a caveat. Diets higher in carbohydrates tend to help preserve protein stores because it is a much more efficient process for the body to convert carbohydrates into glucose (the body’s main fuel source) than it is to convert protein into glucose through gluconeogenesis. For this same reason, the body works much more efficiently when given a higher carbohydrate diet compared to a low carbohydrate diet like the carnivore or ketogenic diet. This has to do with the byproducts created through glucose metabolism (carbohydrates) compared to lipid metabolism.

When the body breaks down carbs into glucose, it releases CO2 into its environment, which encourages surrounding cells to consume more oxygen and eventually break down more glucose. This results in a positive feedback loop, basically telling the cells that we have adequate energy and to keep on using it. Fatty acid metabolism, on the other hand, also releases CO2, but in much smaller amounts. Additionally, fatty acid metabolism is a much slower process than glucose metabolism and releases a number of stress hormones like cortisol and adrenaline. This results in a negative feedback loop in which the cells aim to preserve energy by limiting the further breakdown of carbs and fats.

By consuming very few carbohydrates, we are forcing our body to use fatty acid metabolism as its main fuel source. This can significantly decrease our total energy production (metabolism) and also increase the amount of stress placed on our body. 

Takeaway: All in all, fat loss will be a much less stressful process on our body if we allow our body to use its desired fuel source. 

The Essential Fatty Acids

The Essential Fatty Acids:

*Hint - They’re not essential*

Dietary essentials are anything that we must consume through our diet because our body is incapable of producing them and requires them to function optimally. The two “essential” fatty acids are the omega-6 and omega-3 fatty acids. These are both types of polyunsaturated fatty acids and are named by where the double bonds occur in their structure. Omega-3 fatty acids have a double bond between every 3 carbon molecules, while omega-6 fatty acids have a double bond between every 6 carbon molecules. It should now make sense why cold weather animals like fish have a much higher concentration of these “essential fatty acids” and why polyunsaturated fats like these are not optimal for humans to eat, but this leaves the question of why are these fats considered essential. 

In 1929 George Burr made his essential fatty acid hypothesis claiming that unsaturated fats were necessary to prevent a host of diseases. In the experiment, rats were fed a diet completely devoid of fat, which resulted in a deficiency that could be cured by the consumption of the polyunsaturated fat or omega-6 fatty acid, Linoleic acid. This hypothesis was created before the discovery of most of the B vitamins and essential trace minerals. It was later found that Burr’s disease, which was previously believed to have been a fatty acid deficiency, was actually brought about by a deficiency in the b vitamins and zinc.

In 1938, William Brown,  working in Burr’s own lab, decided to test the essential fatty acid hypothesis on himself and for 6 months did not consume any unsaturated fats. In these 6 months he cured himself of lifelong migraines, lowered his blood pressure, lost 14lbs, significantly decreased his cholesterol levels, and increased his rate of oxygen consumption (signifying an increased metabolic rate). Later studies done on essential fatty acid deficient rats also showed they had increased metabolic rate and therefore an increased nutritional requirement, meaning that they needed more vitamins and minerals than their unsaturated fatty acid consuming comrades. 

The Omega-9 unsaturated fatty acid is the only form of polyunsaturated fatty acids that our body naturally produces on its own and might actually be essential to function optimally. Healthy sources of omega-9 fatty acids can be found in olives, avocados, olive oil, and avocado oil. 

Hydrogenated Fats

Hydrogenated Fats:

As we discussed before, polyunsaturated and many monounsaturated fats are naturally liquid at room temperature. In order to stabilize these fats to make them solid or solid-ish at room temperature, they can undergo a process known as hydrogenation2. Hydrogenation is the addition of hydrogen molecules onto the unsaturated fats to replace the double-bonded carbon with a hydrogen bond. Depending on the degree of hydrogenation(how many of the double bonds are replaced with hydrogen bonds) this will stabilize the fat, raising the temperature at which it melts. Effectively converting polyunsaturated fats into saturated fats. The issue with the hydrogenation is that the high heat required to replace the double-bonded carbons with hydrogens can also result in the conversion of the unsaturated fats into trans-fats.

Thermo Approved Fat Sources:

As far as healthy or thermo-approved fat sources, we recommend consuming the majority of your fats from saturated fat or monounsaturated fat sources. For this reason we recommend following the THERMO30 Roadmap to ensure you are consuming high-quality sources of fat pictured below: 

Thermo 30 day roadmap

You can also check out the full Thermo Diet course on our Umzu Fit platform

These fats are consistently made up mostly saturated fats and are generally organically sourced and grass-fed when possible. Organically sourced foods significantly decrease the amount of pesticides we absorb from our food. And grass-fed cows and pigs tend to have a higher ratio of saturated fat to unsaturated fat present in the meat. 


My goal in writing this article, as always, is to provide you with logically-based principles that you can use to form your own conclusions regarding any information you may come across within this subject. I really hope you found this article interesting and if you have anything to add to this article, or any comments or criticism, feel free to reach out to me on our facebook groups (The Thermo Diet Community Group, The UMZU Community Group) or on Instagram @tylerwoodward__. Also, please feel free to share this article with anyone that might be interested.

Thanks for reading!

Until next time… be good

~Tyler Woodward

B.S. Physiology & Neurobiology 


  1. Pamplona, R., M. Portero-Otín, C. Ruiz, R. Gredilla, A. Herrero, and G. Barja. 2000. “Double Bond Content of Phospholipids and Lipid Peroxidation Negatively Correlate with Maximum Longevity in the Heart of Mammals.” Mechanisms of Ageing and Development 112 (3): 169–83.
  2. https://chem.libretexts.org/Bookshelves/