Episode 060: Welcome to another episode of of Real Health Radio. Today’s show is all about dietary fat.
I go though what is fat and what are the different types. We look at the digestion, absorption and transportation of fat. I cover what functions fat performs in the body. And I look at my recommendations and where I stand on fat consumption and the types of fats people should be consuming.
00:00:00
00:02:05
00:04:20
00:14:50
00:16:25
00:22:50
00:25:50
00:37:55
00:42:50
00:46:15
00:50:45
00:54:45
01:03:30
01:06:50
00:00:00
Chris Sandel: Welcome to Episode 60 of Real Health Radio. You can find the links talked about as part of this episode at the show notes, which you can find at www.seven-health.com/060.
Welcome to Real Health Radio: Health advice that’s more than just about how you look. Here’s your host, Chris Sandel.
Hey everyone, and welcome back to another installment of Real Health Radio. This is another show where it’s just me on my own, looking at a particular topic in detail. For this show I’m going to be covering dietary fat. I’ve previously done episodes on carbohydrates and also on protein, both of which were well received, got lots of listens, got lots of emails about. If you haven’t checked those out, I will put them in the show notes, and you can give them a listen after you’ve listened to this one.
Dietary fat is one of the three macronutrients – as I mentioned, carbs and protein being the other two. It’s probably, of the macronutrients, the one that is most maligned and has had the most worry and fear brought up around it. I would say in the last decade or so, some of this has dissipated a little bit and carbs are now taking a lot more of a bashing, but the campaign for low fat eating and the fear of fat has been going on so long that for most people, this is often how they think about fat, and that’s what they have in their mind.
As part of the show today, I’m going to go through what is fat and what are the different types. We’ll look at the digestion and absorption and transportation of fat in the body, what functions fat performs in the body, and then we’ll look at my recommendations in terms of consumption, where I stand in terms of what fats people should be consuming, and how they should be consuming that stuff.
00:02:05
Starting with “what is fat?” – I’m going to be honest: when putting this together I’ve really struggled with this bit, and for a lot of parts of this episode. Part of the reason for this is so much of the talk around fat uses talk around fat structure, and it uses unfamiliar words and relies on an understanding of chemistry, and this can be quite off-putting. I remember in the past where I’d be hearing people talk about this stuff and I would just glaze over and be totally confused – and this still happens when people talk about it in certain levels of detail.
The other thing is, it’s also a lot easier to explain this when there is a visual representation so you can be looking at something alongside me talking. But being a podcast, we don’t have that, so I’m going to just keep it super simple and tell you the most important stuff for you to understand.
Fats are chains of hydrogen and carbons that at one end have a carboxyl group. For anyone who is not versed in chemistry, that probably means absolutely nothing. The best analogy that I can use to help you imagine what fat is is to compare it like a chain of a simple bracelet or a necklace that hasn’t been done up and is just lying on a dresser or a table. At one end you have a clasp, which is the carboxyl group, and then the rest of it is just this long chain of interlinked little chains the whole way along.
Fats come in varying lengths, just like say a necklace or a bracelet. We break fats down into four different categories: short, medium, long, and very long. If a fat has fewer than 6 carbons (or 6 chain links), it’s known as short. If it has been 6 and 12 links, it’s known as medium. If it has been 13 and 21 links, it’s known as long. And if it has more than 32, it’s known as very long. Most people are not going to need to know that, but I just wanted to explain it in case you’re wondering, when someone says a medium chain fat or a short chain fat or a long chain fat, what that actually means.
00:04:20
Fats are also classified depending on whether they are saturated or not, and there are three options here. You have saturated fat, you have monounsaturated fat – that’s unsaturated, mono meaning one, so monounsaturated fat – and then you have polyunsaturated fat, poly meaning many. Many unsaturated fat.
To explain this, I’m going to again leave the chemistry out of it and just do it from a visual perspective, continuing on with the bracelet analogy. A saturated fat is one that is a chain that is completely straight. If you have that bracelet, it’s lying on the table and it is completely straight without any bending. It would therefore be a pretty rubbish bracelet, as you wouldn’t be able to do it up because it’s more straight like a ruler.
A monounsaturated fat is where you have the chain, but it’s straight except for one kink. Let’s say that bracelet is lying flat on the table and say a third of the way down the bracelet at one of the links, it bends, and then at this point it continues on again in a straight line. So it’s straight, it bends at one point, and then it continues to be straight again.
The final option is then polyunsaturated fat. This is a chain where there are multiple kinks or bends, so a chain that has five different points at which it bends. It’s straight, then it bends, then it’s straight, then it bends again, etc., etc.
Fats are classified based on the length of the chains, or how many links there are, and whether it has different kinks (if it has zero kinks, it’s known as saturated; if it has one kink, it’s known as monounsaturated; if it has multiple kinks, it’s known as polyunsaturated), but also where those kinks appear.
Each of those different variations in terms of length, the number of kinks, where they appear, each then forms a different type of fat. For example, a saturated fat that is three links long is known as propionic acid, if it is four links long, it is known as butyric acid, and so on. Just within saturated fats, there are 36 different types of fats based on the length of the chain. Each of these different fats behave slightly differently and have different functions within the body.
Then within unsaturated fats, you have both the length of the chain, but also the number of the kinks and where those kinks appear. For example, you can have two fats that are both monounsaturated, so they each have one kink, and they can both be the same length. But for one of them they have their kink at the ninth link in that chain, and for the other, they have a kink at the eleventh link in the chain. Both of these would have a different fatty acid name. The same then applies with polyunsaturated fats.
This alone, you can start to see just how many different types of fats there really are. Each of them has, as I said, a slightly different role in the body and behave slightly differently. With polyunsaturated fats, you’ve probably heard people talk about Omega-3s or Omega-6s or Omega-9s. These numbers indicate not how long the chain is, but how many links from the tail end of the chain before there is a kink for example, for an Omega-3, it has a kink that is the third link before the end of the tail. If it was an Omega-6, it would have a kink at the sixth link before the tail end.
You can have many other kinks throughout the chain, but it’s where that last kink appears that determines whether it is an Omega-3 or an Omega-6 or an Omega-7 or an Omega-9. It also therefore means that there can be lots of different types of Omega-3s depending on how long the chain is, but also how many different other kinks there are prior to that last one and where the last one is on the chain.
The final type of fat I haven’t mentioned that most people have also probably heard of is trans fat, which is actually a type of polyunsaturated fat. Trans fats are fats that occasionally appear in nature, but are much more likely to be manmade through a process known as hydrogenation.
When trans fats appear in nature, they are actually quite health-promoting and they aren’t associated with negative outcomes. Manmade trans fats, on the other hand, aren’t good for health. This is something I’ll cover a little bit later on, but to start with, let’s just look at how manmade trans fats are created and I can explain this a little more.
Polyunsaturated fats, because of their chemical structure, have a much lower solidifying points. For example, if you have coconut oil, which is a saturated fat, sitting on your countertop, most of the time it’s going to be solid – or at least, living in the UK it’s going to be solid most of the time. In the middle of summer, some of the days maybe it’s turning to liquid, but most of the time, because it’s a saturated fat, at room temperature it is going to be hard.
Olive oil, which is a monounsaturated fat, when sitting on a countertop is always really in liquid form. At room temperature, it is a liquid. If I were to then put that olive oil into the fridge, it may start to get a little thicker, and if I then started to turn the temperature down, it would become more solid.
You then have something like a fish oil, which is a polyunsaturated fat. If this is left on the countertop, it’s going to be liquid. If you put it in the fridge, it still remains liquid. If you put it in the freezer, it’s probably going to start to get thicker, but still could be liquid. You have to take it down to colder and colder temperatures before it starts to solidify.
All of this starts to make sense if you think about where these oils are found and what they do. For example, polyunsaturated oils are found in decent amounts in seeds, for example. Seeds will typically have to germinate in the springtime, when the temperatures are still quite low. If the seed was filled with saturated fat, they would be rock-hard and you wouldn’t be able to have that germination happen. But because they’re filled with polyunsaturated fats, they remain more of an oil even in those cold temperatures instead of solidifying, and it means that germination can happen.
Or if you think about with fish oils – say something like a trout – they are swimming in streams that are often very, very cold. If they were filled with saturated fats, they would be rock-hard in these temperatures and they wouldn’t be able to swim. But if they are filled with polyunsaturated fats, they are still able to stay as an oil even in those cold temperatures and they’re able to move properly and swim properly.
As human beings, we run at a much higher temperature. Even if we are say living in the Arctic, our body temperature is still going to be somewhere around 36 to 37 degrees Celsius, or 97 to 98.6 Fahrenheit. I know this will differ depending on other factors; you can get a little bit lower than this. But at these kinds of temperatures, saturated fats are then going to be turning into oils instead of being solid. We are not like the trout. We can have saturated fats within us without it solidifying because of the temperature.
Bringing all of this now back to trans fats, if you have something like a vegetable oil, this is going to be liquid at room temperature. Back in the 1890s, a gentleman called Paul Sabatier worked out a way of changing vegetable oil so it could become solid at much warmer temperatures. Because it’s then solid at much warmer temperatures, it reacts in a similar way that we’d expect saturated fats to react at those temperatures. It’s this discovery that then led to margarine, which is a vegetable oil that reacts in a similar way to butter in terms of how it’s impacted on by the environmental temperature.
The process that was discovered was called hydrogenation. Rather than getting into the chemistry side of it, let me bring it back to the bracelet analogy so you can understand.
I said with monounsaturated fats and polyunsaturated fats, the bracelets would have kinks in them. These kinks always happen in one direction. If the bracelet is lying on the table, say for example the kinks are always going to go to the left. If there are three kinks, each one will happen to go to the left and to the left and to the left.
With trans fats, through the process of hydrogenation, the kink starts to go in the other direction. Whereas they would always go to the left before, now they will always go to the right. The kinks also become much smaller, so they are almost straight. Because they’re nearly straight, they’re able to stack much closer together in a similar way that saturated fat does, which then allows it to become solid at room temperature and behave more like a saturated fat in relation to environmental temperature.
Just so you know, polyunsaturated fat in its natural state is known as a cis fat, and a polyunsaturated fat that has been hydrogenated and converted is known as a trans fat.
00:14:50
The final thing I want to mention in this section on fat is triglycerides. You’ve probably heard the term “triglyceride,” and you may even have negative connotations when you hear it. You think of cardiovascular disease or something similar. But actually, a triglyceride is just three individual fats that are bound together. You can imagine those three bracelets lying parallel to one another, and there’s just a bit of sticky tape at the end connecting them. The tape is a substance called glycerol, and it holds the three fats together.
This is how fat is mostly found in the human body and in animals, but also how it’s found in vegetables and other non-animal sources that contain fat. So while the term “triglyceride” might conjure up certain thoughts, triglycerides aren’t bad. This is really just the structure that fats like to be in.
If you’re wondering, the three bracelets that are then connected together as part of the triglyceride, each of the bracelets can be a different type of fat. You could have a triglyceride that has all of the three fats be saturated fats, but each of the bracelets is a different length, so it’s a different type of saturated fat. Or you can have one that’s saturated fat and two that are monounsaturated fat, or one saturated, one monounsaturated, one polyunsaturated. Basically the combinations are endless. But just so you know, with those triglycerides, they can be different types of fat.
Hopefully that gives you a bit of an understanding about fat and you’ve been able to follow along and it hasn’t been too confusing.
00:16:25
I now want to look at the digestion of fats. Just like I’ve been talking here, the digestion of fats is also fairly complicated, and it’s more complicated than carbohydrate digestion or protein digestion. This is largely because fat isn’t water soluble and it aggregates together, making it more complex to break down. It forces the body to have to add in extra steps that aren’t then needed for things like carbohydrates and protein.
I’m going to walk you through the digestion, but like with my explanations earlier on, I’m going to try and keep things really simple so that anyone can understand it, even if you don’t have a background in physiology.
The process of fat digestion starts in the mouth, although this is a very preliminary stage. Chewing food into smaller particles helps to break up fat, but this is probably more relevant for things like protein and carbohydrates than fat digestion. In the mouth, you release a chemical substance called lingual lipase. Lingual means the tongue and lipase refers to an enzyme that works on the fat, so it’s an enzyme in your saliva, and it begins to emulsify the fat.
The word “emulsify” is common when talking about fat digestion, but you probably might not know what it means. Imagine you have a glass that you put some water into. You then pour some olive oil into that glass, and what happens? The oil sits on the top, and all the oil forms one big mass, so it’s just one big blob. Emulsifying the fat is when you then start to break this one big fat into smaller and smaller individual droplets instead of just having one big mass. By breaking them into smaller and smaller droplets, the body is then able to do the processes to digest them that I’ll talk about in a little bit.
As I mentioned earlier, fats in their natural state like to stay as triglycerides. (Those are those three bracelet chains that are stuck together.) Imagine that in this glass of water, or when the fats are together, that there’s 1,000 triglycerides. There would be huge amounts more, but I’m just using simple math here to explain the concept. Emulsification is taking this one group that is all together that is 1,000 and then splitting it into two groups where there’s 500 each, then three groups, then four groups, and so on, with the end goal being to get them to be single triglycerides. But to start with, you’re just taking those bigger groups and splitting them into smaller and smaller ones.
The process of emulsification starts in the mouth due to that lingual lipase, and as I said, it’s just the start of that process. The fat then, along with the rest of the chewed food, makes its way into your stomach. In the stomach you release a thing called gastric lipase, which is very similar to lingual lipase apart from the fact that it is released in the stomach as opposed to from the tongue.
Both lingual and gastric lipase are most important during infancy because they help to break down the fats in mothers’ milk. As adults, these lipase are important, but we have much more developed digestive capabilities further down in the small intestine. We’re able to produce more enzymes in the pancreas in much higher amounts than we are as an infant. Really, it’s the small intestine that is the main site for fat digestion once we move out of being an infant.
When the food moves from the stomach and then into the small intestine, it first enters into the upper portion to the small intestine that is known as the duodenum. When that happens, hormone signals are sent to both the gallbladder and also the pancreas. The gallbladder releases a substance called bile and the pancreas releases a substance called pancreatic lipase, and both of these are important for fat digestion.
Starting with bile, the bile continues the process of emulsification. It’s breaking those fats down into smaller and smaller groups. But as part of the process of emulsification, it is also adding a coating or a substance to the fat that then prevents them from clumping back together. If you’ve got a group of say 20 triglycerides and then they’re broken into a group of 10 and then 8 and then 5, you’re breaking them down, but you’re making it so that they then won’t bunch back together. The end goal as part of this bile and that process is you’re breaking them into single triglycerides. Because they’ve been coated in this substance, they aren’t forming back together.
It’s then the job of pancreatic lipase to work on these triglycerides. It then breaks them down even more. As I mentioned, a triglyceride is those three bracelets that are stuck together, and the pancreatic lipase then breaks them into single bracelets, which are known as monoglycerides (mono meaning one), and then further breaks them into free fatty acids, where you just have the single fat and then the glycerol is separated for it. You then have free fatty acids and glycerol, or you have them as monoglycerides.
Once the fat is then broken down into those two things, whether it’s monoglycerides or free fatty acids, they then start to be absorbed through the mucosal lining in the small intestine and enter into a thing called epithelial cells. Basically, the fats are broken down into single molecule forms and then they enter into a cell that is just across the other side of the small intestine.
They then go to a special place inside these cells which has a job of making them ready to travel round the body. Here they are reconstructed back into those triglycerides, because as I said, that’s really the form that they prefer to be in.
00:22:50
They are then turned into a thing called chylomicrons, which I’m probably butchering in terms of how to pronounce it. Chylomicrons is probably a term you haven’t heard before, so let me explain it.
For a fat to move around the body, it needs to be transported. Yes, you can have free fatty acids in the blood, and yes, you can have triglycerides that are in the blood, but the majority of fat that is being moved around the body is being transported. The things that transport these triglycerides is a special kind of protein. If you can imagine, the triglyceride is getting into a little car, which is then the protein, and then this car shuttles it around the body.
In this vehicle or the car, it’s not just triglycerides, but you also have small amounts of cholesterol and you have fat-soluble vitamins. These are vitamins A, D, E, and K. The term chylomicrons refers to the triglyceride, the protein vehicle, the cholesterol, and then the fat-soluble vitamins that all travel together around the body.
While you probably haven’t heard the term “chylomicrons,” you have heard of other transport proteins that help to transport fat and cholesterol around the body because you’ve undoubtedly heard of LDL and HDL, which stand for low-density lipoprotein and high-density lipoprotein. These are all doing similar things. These are transporters of fats and cholesterol and fat-soluble vitamins around the body.
Once the fat has then been turned into the chylomicron, it is then released into your lymphatic system. Your lymphatic system is like a highway that runs next to your blood supply. Things move from the lymphatic system into your blood supply and then vice versa. For example, most of your immune system, your white blood cells, they travel in your lymphatic system. They move into your blood as they need to be doing stuff, they pull back into your lymphatic system. It’s just something that runs along your blood supply.
Once these fats are into your lymphatic system as the chylomicrons, they are then sent around the body to wherever they’re needed. They can travel to your cells to be used for energy. They can travel to your liver and be converted into different types of liver proteins. They can travel to cells to provide them with cholesterol, to create hormones, to provide them with fat-soluble vitamins. Or they can travel to certain locations and be stored in fat cells and be used at some point in the future.
That explains fat digestion, and again, hopefully I’ve kept this easy enough so that you can understand and light enough that you haven’t wanted to switch off just yet.
00:25:50
The next thing this then brings us onto is what are the different roles that fat plays in the body? I briefly touched on them just now, but I want to go through it in a bit more detail.
The first is that fat is required for the production of certain hormones. This can happen for a number of reasons. Fat itself is used to make certain hormone-like substances that are needed for the signaling for cells to make hormones. Without these substances, the cells don’t get the message that certain hormones are needed to be produced or aren’t getting the message they need to be produced in the right quantities.
Fat is also found and associated with cholesterol in foods, and cholesterol is needed as the raw material to make steroid hormones. Steroid hormones are things like estrogen and progesterone and cortisol and aldosterone and many other hormones. You need cholesterol as the raw material to actually make those hormones.
While you can have a food that is high in fat and low in cholesterol, you don’t typically find foods that are high in cholesterol but low in fat. Cholesterol is always found where there is fat in decent amounts. In terms of looking at fat and hormones, maybe in terms of its production, it’s more the cholesterol than the fat. But because the two often appear together, it can often be difficult to separate them and talk about them and know which is more important for production or having the impact.
I would also add the same comments here with fat-soluble vitamins. Lots of the functions that are accredited to fat when you look at the functions it has in the body are things like wound healing, bone formation, supporting the retina in the eye. A lot of these are probably coming from the fat-soluble vitamins as much they are fat itself. But again, because fat-soluble vitamins are regularly found in the foods that contain the fats, and because you need fats to help with fat-soluble vitamin absorption and digestion and transportation, we often put the two of them in the same category.
Getting back to hormone production, body fat can also be really important for hormone production – both for reproductive hormones and for thyroid hormones, but for other hormones as well. This can have an impact depending on where someone falls on the body fatness spectrum. You can be getting problems if people are too low, just as you can be getting problems if people are too high.
At low levels, it’s not uncommon that this then suppresses reproduction and reproductive hormones and also suppresses thyroid function and thyroid hormones.
This makes total sense. If you have really low body fat, your body can often interpret this as you are in a famine. If you’ve got little amount of food coming in versus the amount that you’re using and this means you’re getting lower and lower supplies of fat and you’re getting leaner and leaner, your body is less likely to prioritize reproduction. This is especially true for women because if your body is worried that you’re not bringing in enough food just to get you through the day, it’s not going to want to risk you getting pregnant and then having an even further drain on that situation. So it’s not going to be prioritizing reproductive hormones.
From a thyroid perspective, your thyroid gland and your whole thyroid system is one of the main determiners of how many calories you use and how much energy you’re producing. If it notices that your fat reserves are getting lower and lower, it’s going to be much more likely to be slowing energy production and use down as a protective mechanism. It’s going to be worried that you’re going to be running out of things, so it pulls down your thyroid function. That then starts to turn off other functions or turn down other functions within the body.
I’ve actually done a whole podcast on issues that relate to reproduction and going into more detail about some of this stuff as well as explaining other factors. If you want to check that out, you can find it at www.seven-health.com/025. I’ll also put all of the different links in the show notes for this show, which is www.seven-health.com/060.
At the other end of this spectrum in terms of weight, having higher amounts of body fat could also start to create a problem. Body fat isn’t inert on the body, but actually has functions similar to an endocrine organ. The word “endocrine” means hormone, so the higher body fat starts to have a greater impact on hormone production and hormone function within the body. You can have it affecting things like reproductive hormones or thyroid hormones or inflammation or blood sugar, and much more.
This isn’t to say that people need to then go on a crash diet to reduce body fat or that other dietary or lifestyle changes can’t mediate some of or all this stuff. I think we have a completely unrealistic standard about what a healthy body looks like. I’m a big one for body diversity, but fat in and of itself can have a negative impact. Whether or not someone can then do anything about that is a different story, but I don’t want to pretend like it can’t or it doesn’t have an impact.
That’s it with hormone production. Fat also has a role in the body as a source of energy. Like carbohydrates, fat can be broken down and used for energy by our cells. It’s converted into ATP, or cellular energy. There’s lots of arguments on both sides of the aisle about which is better and what people should be having in their diet, and people saying that you should be keeping your carbs really low and it should be all fat, and people saying basically the opposite.
Personally with clients, I tend toward them having more of the higher carb side of things than the higher fat side of things. But this is very much down to the individual. We try and work out what works better for them, because I do think that both methods on paper have both advantages and disadvantages. It just comes down to what works for that individual.
Fat is also talked about for its ability to create satiety. People often say one of the roles of fat in the body is to increase the satiety that we get from a meal, and that if you increase the fat, it will increase the ability to feel full after a meal, and that sensation lasts for a longer time.
This one probably isn’t as true as most people have made out. Of all the macronutrients, protein is the one that has the most significant impact on satiety. Carbohydrates and fat are then fairly similar in terms of satiety. Maybe fat has a slight advantage. But there’s two things I want to mention with this.
The first is that satiety can often be created by reducing the reward and the palatability of food. For example, if you go on a high fat diet, in the beginning it might be exciting, but the longer that you’re having high amounts of bacon and butter and avocado at every single meal, the more the novelty wears off. If you’re then avoiding or limiting carbohydrates and only eating these high fat meals, then you can get a spontaneous reduction in food intake and a lack of reward from eating it, and that can then feel like, or people then say, “that leads to more satiety, so I’m eating less.”
But this isn’t because of the power of fat on satiety, and more to do with reducing the palatability of food. If you did the reverse and you kept your fat incredibly low and increased your carbohydrates, you would also get the same phenomenon. Initially you might be like, “Wow, I get to eat all of these carbohydrates. I get to be having tons of fruit.” But after a while it just gets a little bit more boring, and slowly you start to eat less calories. That happens until you start to feel completely bored and you start to feel deprived, and then you quit, and then you eat high amounts of whatever macro you’ve been shunning.
The other part with the satiety side of things is that fiber has a huge impact on this feeling. If you’re having a meal that is high in fat but is low in carbohydrates and also, because of that, low in fiber, then you might not feel so satiated. Just like if you’re having a high carbohydrate meal but those carbohydrates are coming from things like fruit juices or fizzy drinks, you’ve also had a situation where the fiber has been removed and it’s not so satiating.
While I think fat can be satiating, it’s a factor that’s probably overblown in its importance when talking about the benefits of fat.
Fat is important for brain and nervous system function. Your brain is made up of high amounts of fat and needs a regular supply of it to function properly. For our nerve cells, they are insulated by a thing called the myelin sheath. This is an equivalent of the insulation that covers an electrical cord. Your nervous system is running electrics through your body, so it helps to keep the current running along the nervous system. Fat is essential for the maintenance of the myelin sheath, and is one of the substances that it is made out of.
Another role for fat is for the cell membrane. This is the perimeter of the cell, which keeps the things on the inside and the outside separate and what helps to choose what can come into the cell and what can come out of the cell. This one is a little bit more questionable as well for me.
A number of episodes ago, I had Brad Abrahams and Jeremy Stuart on the show. (Again, I’ll link to it in the show notes.) They were talking about a documentary they’d made called On the Back of a Tiger. Part of the film challenges our understanding of physiology. Certain experiments that have been done by people like Harold Hillman and research that has been done by people like Gerald Pollack would question the validity of the idea that the cell membrane is this fatty layer that it is often made out to be.
So even if it has got some fat in the cell membrane, it’s not nearly as important as it’s made out to be, and it’s not just fat the way that it’s made out to be. If anything, it’s going to be more protein than fat. But the importance of that cell membrane isn’t as important as it’s made out to be.
That’s it for the roles of fat in the body. There are probably others that I’m missing, but those are the main ones that come to mind. As I said, there were some others that I briefly touched on that I think probably relate more to the fat-soluble vitamins as opposed to the fat per se.
00:37:55
I now want to talk about the categorization of fats that we typically use. I said earlier that fats can be divided into different categories based on their chemical structure. While we can break fats down based on their length – whether they’re short chain or medium chain – the majority of time when people break fats down and we talk about it, we talk about saturated fats, monounsaturated fats, polyunsaturated fats, and trans fat.
Something I want you to understand – and this is something I don’t think most people get – is that when we use those labels, we really simplify things. If I were to say to you, “What type of fat is butter?”, you would probably quickly say it is a saturated fat. Or if I was to say to you, “What type of fat is olive oil?”, you may immediately think olive oil is a monounsaturated oil.
This isn’t totally correct, because butter does contain a lot of saturated fat, but it is not all saturated fat. If you look at the fat profile of butter, 65% of it is saturated fat, 25% of it is monounsaturated fat, 5% is polyunsaturated fat, and 5% is trans fat.
You may be thinking, “Trans fat in butter? I thought trans fat only appeared in margarine, not in butter.” I mentioned earlier that trans fats can naturally appear in nature, and when they do appear in nature, they aren’t damaging and they’re actually health-promoting. The trans fat that is found in butter is one of those naturally occurring, healthy trans fats. It’s known as conjugated linoleic acid, or CLA, and it’s actually beneficial for things like heart disease and atherosclerosis.
But getting back to the point I’m trying to make, when we say that butter is a saturated fat, it’s not because it only has saturated fat in it; it’s because, of the different types of fats, saturated fat is the one that is the highest percentage.
Then looking at olive oil, to further demonstrate this point, it contains about 75% monounsaturated fat, 15% saturated fat, and 10% polyunsaturated fat. But we call it a monounsaturated fat because that is the fat that accounts for the highest percentage.
This shorthand way of thinking about fats can obviously cause problems. A perfect example of this would be when we make generalized statements. Often people talk about lard as being a saturated fat, but if you look at the actual breakdown of fats, it’s about 48% monounsaturated fat, 38% saturated fat, and 14% polyunsaturated fat. These numbers can change a little bit depending on the diet of the pig, but that’s the rough makeup. This would mean that lard is actually a monounsaturated fat rather than a saturated fat despite how it’s often referred.
Often lard is used in experiments as a saturated fat, and then the outcome, depending on what happens there, whether it be a good outcome or a bad outcome, is labeled as saturated fat being the reason for that outcome.
You then have something like say coconut oil, which is over 90% saturated fat, 6-7% monounsaturated fat, and then the small remainder being polyunsaturated fat. The fat profile of lard and coconut oil are incredibly different. Lard is about 40% saturated fat; coconut oil is about 90% saturated fat. And yet we typically lump these two into the same categories when we talk about saturated fats.
This can then obviously be very problematic if you’re doing research that uses lard and then you make comments about saturated fats, and that then includes coconut oil in those comments because you put those two in the same category.
On top of this, we have the individual types of fatty acids that make up the profile of each of them. How long or short the fats can be can impact on their behavior and what they do within the body. I know I’ve been talking about saturated fats here (or supposed saturated fats if we’re talking about lard), but this holds true with monounsaturated fats and polyunsaturated fats as well. Making sweeping statements that whole categories of fats are good and bad is completely missing how complex this really is. The categorization of fats into saturated or monounsaturated or polyunsaturated really only tells us a very small amount about that fat.
00:42:50
I now want to briefly go through the different sources for each different fat. As I’ve just explained, it doesn’t mean that these are the only fats that this source has in it. It just means that this type of fat is the one that is in the highest amount within that food.
Foods that are referred to as saturated fats and contain this as their highest fat are: butter, cream, cheese, ghee, suet, tallow, fatty cuts of meat, coconut and coconut oil, palm oil, cocoa butter, chocolate, macadamia and macadamia nut oil, milk, and bone marrow. Not all of these are high fat. For example, milk, even if you’re drinking whole fat milk, contains a pretty low amount of fat. Low fat cheese would still be considered a saturated fat. It just means that of the fats that they have in them, saturated fat is the one that is in the highest percentage.
The next category then is monounsaturated fats. Fats that contain the highest amount of their fats in monounsaturated fats as a percentage are things like: olives and olive oil, canola oil, sunflower oil, sesame oil, avocado and avocado oil, peanuts and peanut oil, cashews and cashew nut oil, and then some salad dressings.
Polyunsaturated fats, which are often shortened to PUFs, are broken down into different categories. These are different Omega categories. There’s actually four different types of Omega categories. There’s Omega-3, Omega-6, Omega-7, and Omega-9. But the ones that are of most interest are the Omega-3s and Omega-6s. These are the ones that most people talk about, so I’m just going to cover these two categories
Starting with Omega-3s, the foods that have Omega-3s behind their highest fat category are things like: oily fish and fish oils, algae, flaxseed and flaxseed oil, chia seed and chia seed oil, and dark green leafy vegetables – things like mustard greens and collard greens and kale and spinach.
The final category is Omega-6s. The foods that have the highest amounts of these fats are: nuts – nuts like almonds and pecans and pistachios and walnuts and hazelnuts – and seeds and seed oils – things like pumpkin seeds, safflower, sunflower, evening primrose oil, black currant oil, soybeans and soybean oil, hemp oil, borage oil, and corn oil.
Undoubtedly I probably missed some things in these lists, but that should give you a bit of an idea. I will just add that although say peanuts are in the monounsaturated fat category because this is the highest fat they contain, they also contain very high amounts of polyunsaturated oils, particularly Omega-6. In fact, they contain pretty much the highest amount of Omega-6 of all the nuts apart from maybe walnuts.
Now that we’ve gone through the different sources, I want to look at recommendation around fats and what you should be eating.
00:46:15
If I’m being honest, this is something I vacillate on. There are so many conflicting ideas about what people should be doing, often sitting at very opposite ends of the spectrum, that it is hard to know what is correct. But I’ll give you my take of where I am now, which is, like most of the sessions I make, pretty moderate – or at least, I think that they’re fairly moderate.
To start with, I just want to give you an idea of some of the different camps when it comes to fat intake, and then I can tell you my opinion.
First you have those who think you should be keeping your fats really low. This is basically fats across the board, but especially things like saturated fats and trans fats. Someone like Pritikin, who is probably the poster child for something like this, recommending that people eat very low fat with a very high fiber diet.
You then have more of the mainstream view, which is following the advice of the food pyramid or the food plate, depending on which country you’re in. The suggestion here is also to keep fat low, but probably not to the same extent as the real low-fat movement. Again, there is a shunning of saturated fats and trans fats, but there’s a real push for people to be eating more of the polyunsaturated fats, whether that’s coming from oily fish or using vegetable oils or vegetable oil spreads like margarine.
Just as a side note, because of research about how bad trans fats are, products like margarine that used to be created by hydrogenation are now not made in this way. Instead, they now add a small amount of palm oil or palm kernel oil, which is a saturated fat, and this allows it to then stay solid at room temperature without the need for hydrogenation. It’s why margarines are now a lot more spreadable when they come from the fridge, because they don’t go so hard as they did before because they haven’t had that hydrogenation process. So they’ve got more of the vegetable oils remaining more like vegetable oils in them.
The mainstream message here is that you want to keep fat on the lower side, and if you are to be having fats, you want to be much more learning towards the polyunsaturated fats and nothing else.
You then have people in the paleo movement and other movements as well who disagree that fats should be kept low. They think that there’s nothing wrong with fat taking up a larger percentage of calories. They also rally against the notion that saturated fat is bad and believe that this should actually take up a larger percentage or a larger chunk of the fat that we consume. They also typically believe that polyunsaturated oils might not be as good for us as it’s made out, and particularly things like Omega-6 oils, especially if they’re coming from sources like vegetable oils.
You then have people like Ray Peat, who is very pro saturated fat and anti polyunsaturated fat, really regardless of the source. While the paleo movement and other movements may talk about Omega-6s being bad and that Omega-3s are good, Ray Peat really believes that both Omega-6s and Omega-3s are problematic and they should be kept as low as possible. He’s definitely not a high fat guy and he doesn’t think that people need to be eating ladlefuls of coconut oil or butter, but he feels that people should be including fat in their diet, and when they are including fat in their diet, that it should be of the saturated fat variety.
Then the final broad category are those that believe in a very high fat diet or even a ketogenic diet. For this kind of protocol, you’re looking at around 65-70% of your calories coming from fat – even more, often – maybe 15-20% coming from protein, and then a very small percentage, normally in the single digits, coming from carbohydrates. Typically this diet, again, is very pro saturated fats and often things like short chain and medium chain fats, so very pro things like coconut oil.
Those are the general camps. I’m massively generalizing things here, but just to give you a bit of an idea.
00:50:45
Where do I stand on all of this? Personally, I’m fairly pro saturated fats. I think there is plenty of research to show that they are not only not as harmful as we used to think or were made out, but they are actually beneficial. This doesn’t mean that people need to be eating huge amounts of coconut oil or they need to be putting butter and coconut oil in their coffee like Bulletproof Coffee suggests. But I am encouraging of people to be using these fats and oils as part of their regular diets.
The benefits of saturated fats are especially important when it comes to things like cooking. The more unsaturated an oil is, the more vulnerable it is to heat and light and oxygen. This means that cooking with something like a saturated fat doesn’t create negative changes in the oil in the same ways as when you’re cooking with an oil that is more unsaturated.
One thing I do want to mention with this is often people say that if you heat an oil too high – say you’re heating olive oil too high – that you will turn it into a trans fat. This isn’t true. To turn a cis fat into a trans fat, you need to take it through a particular process, and part of this process is adding hydrogen to it – which when you’re cooking, you are not doing. Maybe if you’re Heston Blumenthal or something along those lines you may be doing it, but generally if you are cooking something in an oven or in a frying pan and you heat the oil too high, it does not turn into a trans fat.
There are problems with heating an oil too high, and it can create different substances that aren’t good for health, but these substances aren’t trans fats.
On the topic, then, of polyunsaturated fats and whether or not they should be included in the diet, one of the big things that people talk about is that you want Omega-3s and Omega-6s to be in a fairly balanced ratio between the two. It’s still up for debate what is the exact ratio that should be aimed for, but maybe somewhere around 1:1 or 1:2 for Omega-3s to Omega-6s.
Over the last 100 years, we’ve had a huge shift towards using vegetable oils in our diet as opposed to other fats that are incredibly high in Omega-6s, but are very low in Omega-3s. This means instead of having a ratio of say 1:1, we’re looking at a ratio that’s more like 1:15 or 1:20 or often much higher.
Typically when people talk about Omega-3s, they talk about them being anti-inflammatory, and when they talk about Omega-6s, they talk about them being pro-inflammatory. This is a gross oversimplification of things, but let’s just leave it at this level for today.
There is nothing wrong with having something that encourages inflammation. It’s part of the healing process in the body. It’s important for our immune system. But when pro-inflammatory substances are in a very, very high amount while anti-inflammatory components are very, very low, this is going to cause a problem.
If you look at a lot of the chronic conditions that we are suffering with today – diabetes, heart disease, cancer, autoimmune issues – inflammation is a big component as part of them. This isn’t to say that it’s all Omega-6’s fault, but having excessive amounts of these oils in the diet is probably not helping.
My thoughts on polyunsaturated fats is that people need to be getting some of them in, but they should be trying to get a better balance between Omega-3s and Omega-6s. This often means increasing some of the Omega-3 intake, but also reducing a lot of the Omega-6 intake.
00:54:45
But one thing that I want to suggest around this, which is probably just as important for the ratio, is the difference between foods that contain these oils and the refined oils themselves that you buy in the grocery store or the health food store. As I mentioned earlier, the more unsaturated an oil is, the more it reacts to heat and light and oxygen. When these oils are in foods – say you’ve got some nuts and you’ve got some polyunsaturated fats in those nuts – they are then surrounded and supported by vitamins and minerals and other substances that are in that food that then prevent or at least minimize the degradation of that oil.
But when they then extract it and go through a process of refinement, these supporting nutrients and factors are removed. Then they are more likely, when they are exposed to heat and light and oxygen, that they are going to oxidize and start creating substances that are bad for your health. This means that that bottle of vegetable oil that you see in the supermarket is likely to be rancid already sitting on the shelf in the store before you buy it. After it then sits on your stove for 2 months, being opened numerous times, having the exposure of the heat from the stove as you’re cooking, it’s going to be in much worse shape.
This isn’t just for things like vegetable oils. It can also be the same for things like fish oils. I’m going to link to a study in the show notes that appeared in Nature.com from 2015. It was a study from New Zealand that looked at and tested 32 different fish oil supplements, and of the 32 supplements, only 3 of them contained the quantities of EPA and DHA that were equal to or higher than it said on the label. So most of them didn’t contain the thing that it said it would, or didn’t contain them nearly in the level that it promised that it would.
But the other problem was to do with oxidation. These results were equally not very pretty. Only 8% of them met the international recommendations and did not exceed oxidation levels. What this means is basically all of them had started to go rancid, had started to oxidize, had started to have problems within those oils. That means that when you’re taking that stuff in, you’re then exposing your body to those oils that are already starting to degrade.
This is why making recommendations around fats and oils can be really difficult, because if you do a study where you extract an oil from some fish or from some nuts, the results are going to be very different and might not ring true if those oils were consumed as part of their whole foods. While increasing polyunsaturated oils may be helpful, whether this is coming from eating some cashew nuts or some mackerel may be very different from the results of eating cashew nut oil or having some fish oil.
There was a really great article on Stephan Guyenet’s website Whole Health Source. Again, I’m going to put this in the link to the show notes, and you can find that at www.seven-health.com/060. The article is him looking at fat intake between 1980 and 2010, which is a period where there’d been a real increase in weight gain and obesity over those years. The article looked at total fat intake across this period.
When you look at the total fat intake from 1980 through to about 2010, the change is very marginal. Gram for gram, it’s a little bit more, increased by somewhere about 10 grams a day, but in the whole scheme of things it’s pretty small.
Just as a slight side note, for all those people who claim that we started putting on weight because everyone was told to go low fat, even if people were told this message, the data clearly shows that on average, no one really heeded that advice. Going low fat wasn’t the problem, despite what most people may say.
But back to the article. Despite the fact that total fat remained about the same across that time, going up only slightly, what did change was the percentage of added fat in the diet. Whereas before, more of the fat was already being contained in the foods that people were eating – so fattier cuts of meat or some eggs or avocados or olives – during this period, what increased dramatically was the use of seed oils – things like soybean oil and canola oil – and added fats.
What tends to happen when fat is added to food is that total calorie consumption goes up. This isn’t so much from fat. It can be, but it is also from other food sources as well. You have someone who’s going for a skinless chicken breast because it has a lower amount of calories, it has lower amounts of fat grams. They then cook it in some canola oil or they add these oils to their meal, believing it’s heart healthy. In the end, they end up eating more calories than if they didn’t add the oil, and it just had foods that had more of these fats naturally contained in them. And this is before we even think about the damaging effect of the oils that are then being oxidized that are then used as part of this cooking.
Please don’t take this the wrong way and think that I’m saying you have to be eating everything dry and never adding some butter or some oil to a meal. That is not what I’m saying. But if you look at one of the biggest things that have changed in our diet since the 1980s – and probably going back earlier than that, if you look at the information going back even to the turn of the century, so for the last hundred-odd years – there’s been a real change in the amount of oils that we’re using and the types of oils we’re using, but also an increase in that added fat at the expense of foods that already contain those fats.
Really, the take-home message should be that saturated fats aren’t good or bad, and polyunsaturated fats aren’t good or bad. It really does depend on the situation. It depends on the amounts and the quantities. But really, what you should be trying to do is get more of these fats in food form rather than having them as refined or added fats. If you are going to be adding fats and using fats, the safer option is more towards the saturated fats from an oxidization perspective, especially if you’re going to be cooking with them.
This is what I typically recommend with clients. I suggest that they use things like butter and coconut oil and ghee with their cooking, and that they can also be using olive oil, but to save this for more lower temperature cooking than anything else, and for people to be getting the rest of their fat sources from food, and for them to be having things like eggs and liver and meat, and for them to be having seafood and oysters and mussels and prawns and scallops. If they want to be really boosting their Omega-3s, they do it through things like oily fish rather than using fish oil supplements.
On the nuts and seeds front, I know lots of people are very pro nuts and seeds. For me, this is a much more person to person thing. Even though on paper research shows that these can be helpful for certain people, I often find that clients struggle to digest them very well, and when they limit them or they avoid nuts and seeds, they stop getting the gas and the bloating and their digestion will start to improve.
This is kind of like, from my perspective, beans and pulses. I know that there’s lots of research that shows that there is benefits from eating beans and pulses, but in real live human beings, I find that people often don’t do so well on them. So if nuts and seeds work for you, then eat them. If they don’t, then avoid them. There’s plenty of other foods you can be eating.
01:03:30
On the trans fat side of things, people should really be trying to keep these on the lower side unless they are naturally occurring trans fats. I mentioned that butter will have some of the naturally occurring trans fats. These are really common for and are produced by ruminant animals. If you’re having dairy products or meats from ruminant animals, you’re going to be getting small amounts of these trans fats, and there’s nothing wrong with these things. If anything, they’re going to be helpful for you.
But if it is a manmade trans fat, this is when there’s more of a problem. Over the last decade or so, there’s been laws requiring companies to label trans fat on their foods, and because the public have now become aware of the issues they cause, most of these companies have started to reformulate their products so they don’t contain these trans fats and they can label them as “trans fat free.”
This has actually worked quite well. There was a study done by the Center for Disease Control and Prevention, and they found that Americans’ blood levels of trans fats dropped by 58% from 2000 to 2009. So obviously the labeling and the labeling laws have had the desired effect because companies were wanting to take that stuff out of the food.
One thing to be aware of is the allowable amount per serving. The figures I’m going to use here are for the U.S. I couldn’t find anything to do with the UK. But if a product contains less than half a gram of trans fat per serving, it can still be labeled as “trans fat free.” What is important here is “per serving.” It is easy for companies to make servings very small to be able to label something as fat free or trans fat free to get around this.
There have been changes now to the dietary guidelines recently that are going to update and deal with this “per serving” side of things, and the laws are that “per servings” have to be a realistic representation of what someone would normally eat, so you couldn’t make a “per serving” only 15 grams if actually a normal size serving would be 30 grams or 100 grams – which is often what happens to massage the figures to allow something to say “trans fat free.”
Unfortunately, what is now happening is that while in say Western countries we’ve become aware of the problems with trans fats and we’re removing them more from our diet and from products, these oils are now being widely used by developing nations. It’s part of the reason for the growing epidemic of cardiovascular disease in developing nations around the world.
It really reminds me of an episode of Last Week Tonight by John Oliver, all about smoking. Despite smoking figures decreasing drastically in Western countries, sales of cigarettes are still pretty high. The reason for this is that cigarette companies have now made their way into developing countries who aren’t aware of the dangers of them. This is also happening with trans fats. I’ll link to the episode in the show notes with John Oliver. It’s a really well-done thing, so check it out.
01:06:50
The final thing I just want to mention before I wrap this up is to do with calories. For every gram of carbs and protein, they are worth 4 calories. For every gram of fat, it is worth 9 calories. This is generalizing things, but I just want to keep it simple for ease of use.
This means that gram for gram, fat provides double the amount of calories of carbohydrates or protein. There’s often this notion that if you go high fat and low carb, that you can just eat with impunity – that calories don’t matter and they’re this made-up thing, that it’s actually really carbs’ fault, and if you just keep your carbs low, that’s where the problem’s been. So keep your carbs low, you can eat as much fat as you want.
This is total nonsense. Yes, calories in versus calories out is nowhere near as simple as it is made out to be, but to think that it has no bearing on things is just flat-out wrong. If you want to eat higher fat and you feel better and function better on a higher fat diet, then go for it. But please don’t think that you can just eat as much fat as you like and you’re totally immune to weight gain because this is not the case. This can often be with people eating handful after handful of nuts and seeds without realizing how high in calories they are versus other things that they could be possibly eating.
That brings a close to this episode. I know it was a really long one. I know it got a bit technical in parts, so if you’ve made it this full way through, then that is awesome. Hopefully this cleared up some misconceptions and some myths that you’ve heard before about fat.
Next week I am back with a guest. The show is already recorded, and you’re really going to love it. Until then, in the words of Jerry Springer, take care of yourself and each other.
Thanks for listening to Real Health Radio. If you are interested in more details, you can find them at the Seven Health website. That’s www.seven-health.com.
Thanks so much for joining this week. Have some feedback you’d like to share? Leave a note in the comment section below!
If you enjoyed this episode, please share it using the social media buttons you see on this page.
Also, please leave an honest review for The Real Health Radio Podcast on iTunes! Ratings and reviews are extremely helpful and greatly appreciated! They do matter in the rankings of the show, and I read each and every one of them.
And finally, don’t forget to subscribe to the show on iTunes to get automatic updates.
Thanks for joining me on this episode. Here is a link to see the other shows. Until next time!
Policies
Social
Copyright © 2012 – 2023
seven-health.com · All Rights Reserved.
Hi Chris,
Thank you for the interesting information and for analyzing the subject in a critical way. What do you think about cod liver oil? Would you avoid it same as for fish oil? Regarding nuts and legumes you said they can be a problem to be digested for some people. Could this be due to the fact that nuts, seeds and legumes need to be germinated/sprouted first? Last question…I have got a friend who had high levels of blood cholesterol despite the fact she was training for triathlon, very lean girl with problems with her cycle (too frequent or missing) and not eating much fat at all. Do you have any idea on why her cholesterol was high in her situation?