saturated fat - a wolf in sheep’s clothing or A misunderstood boogeyman?

Saturated fat. Some say avoid it like the plague, others seem to tout it like an essential nutrient. As with most things, the truth lies somewhere in the middle. Is it to be feared? Should you avoid it? The unfortunate answer is, it’s not so simple: it depends. It depends on how much saturated fat you’re eating, what the overall composition of your diet looks like, how much fiber you consume, how much saturated fat you eat in comparison to other fat sources (such as poly- and mono-unsaturated fats), what food source you get saturated fat from, how your genetics affect how well or how poorly you process it, your inflammation status, what your overall metabolic state looks like (do you have insulin resistance or obesity), among many other factors. This may not be the simple answer you were looking for, but as with most topics in biology, things are always more complex. Telling someone to avoid saturated fat and, the opposite, not to worry at all, are both far too simplistic. Some people may indeed need to avoid saturated fat as best they can, depending on some of the factors listed above. Others can get away with a lot and not see side effects. The simplest answer I can give is to get your LDL and APOB B checked through blood tests. APO B is the preferred test. It is more precise compared to LDL, but LDL is fine if you cannot find a testing center that will measure APO B. The difference isn’t exactly important to this discussion. Just know that the LDL test came around first, and APO B can be thought of as a more refined version. If these numbers are out of whack, you may need to make some changes. If not, you are probably fine. In the case that you are searching for an avenue to obtain these tests, I personally like using Siphox Health. They have a comprehensive metabolic health test you can do at home that you then mail in. I am not affiliated with this company at all, just a fan.

Saturated fat is implicated in heart disease risk in that it affects blood cholesterol levels. It causes a decrease of the number of receptors on the liver that pull cholesterol carrying molecules out of the blood stream. Cholesterol that is harmful, the term cardiologists use for this being atherogenic, meaning that they contribute to atherosclerosis (the medical term for heart disease), is mainly shipped around the bloodstream in carrier molecules called LDL, low-density lipoproteins. This is why the blood test I mentioned earlier measures this. Cholesterol is a type of fat and blood is mainly water. Fat and water do not mix, so transporting fat requires these special carrier proteins, LDL being one of them. There are also HDL, high-density lipoproteins, IDL, intermediate-density, and VLDL, very-low-density. These all have varying effects on heart disease, which we will not get into. The main one of importance here is LDL. These LDL molecules have a tendency to get lodged in the artery wall and get stuck there, causing a cascading immune response that ends with calcification, hardening, and stiffening of the arteries, making blockages (heart attack or stroke) more likely.

It is important to point out the distinction between dietary cholesterol and saturated fat. Saturated fat is a fatty acid, while cholesterol is one of a class of molecules called sterols. I won’t go into the details, but just know they are not the same thing, and therefore have different effects on the body. For a long time, the recommendation was to avoid dietary cholesterol for heart health, as it was thought that dietary cholesterol would affect serum or blood cholesterol. It makes sense in principle. You eat more, more shows up in your blood, that’s how it works with most other things we eat. Eat more sugar, blood sugar rises, etc.  Since that recommendation began in the 1960’s, scientists have come to the conclusion that there is not really scientific evidence to support this. Dietary cholesterol does not affect blood cholesterol. Dietary cholesterol seems to have been implicated in the place of saturated fat, which most high cholesterol foods also contain a good amount of. One of the theories here is that our bodies down regulate cholesterol production in response to dietary cholesterol consumption in order to maintain a relatively stable pool. Outside of a few rare genetic conditions that affect cholesterol production and regulation, dietary cholesterol is not something to be concerned about. 

Another important point to make is that our understanding of the causal mechanisms of LDL, APO B and heart disease progression are still being worked out. This causal relationship is hotly debated among experts in the field. Some experts see LDL/APO B as directly causal. A higher number over a longer time period leads to more plaque development, full stop. This seems a bit overly simplistic. Others take a more nuanced view. Metabolic health and inflammation status seem to play a role in how harmful LDL is over time. We know that things like insulin resistance and obesity can negatively affect LDL and APOB levels, which will indirectly affect how much saturated fat you can safely consume before it becomes a problem. In simple terms, someone who is metabolically healthy can probably get away with eating more saturated fat than someone who is metabolically unwell. Some take this interpretation so far to say metabolic health is the only driver and LDL therefore should not be paid attention to. I don’t necessarily agree with this view either. The camp I personally fall into is somewhere in the middle. Achieving optimal metabolic health while also keeping LDL and APO B under control seem, to me, to be the best way to mitigate risk. 

For the remainder of this discussion, I am going to simplify things a bit, otherwise this discussion will be way longer than it already is. Regarding saturated fat sources and how they affect disease risk, I will be going by the notion that APO B/LDL are primary risk factors, i.e. directly causal. While I just made the point that I think there is more at play here, for the sake of simplicity, let’s assume from a dietary perspective, anything in the diet that raises LDL/APO B is raising risk.  

From a genetic standpoint, we know that how someone’s LDL level responds to dietary saturated fat varies. Some people seem to be able to eat all the saturated fat they want and their blood levels seem to change very little. Others seem to need to avoid saturated fat entirely in order to keep their LDL in check. The mechanisms here are still being parsed out and are fairly high level, so I won’t go into detail there, but just know that it is important to know how you personally respond to not only saturated fat in general, but also how individual sources affect you. This is why I recommended blood tests. You won’t really know where you stand until you check. Before you knee-jerk start making changes to your diet, which may be completely unnecessary, you should know where you stand and then monitor things, at least yearly if not a few times a year. 

In terms of dietary saturated fat, where that saturated fat comes from matters. I want to start by making a point that I am not demonizing saturated fat. We need some in our diet. It is important for immune function and for creating the myelin sheaths protecting nerve fibers, to give just a few examples. Saturated fats are not bad or harmful in and of themselves, there is just a safe upper limit. Human biology is about homeostasis, a happy medium; not too much, not too little. Just like temperature, ph, electrolytes, or even frankly water for that matter, there is an optimal amount, and there is such a thing as too much. 

We can first begin by discussing processed foods. A diet composed of a lot of ultra-processed foods does not affect cholesterol levels in the same way as someone primarily eating a whole food diet. Saturated fat from whole foods is not the same as saturated fat from processed foods. Our body metabolizes them differently. Saturated fats from processed foods are generally worse gram for gram than their whole food counterparts. This is another instance of the medical community not yet knowing why. All we can tell is that ultra processed foods seem to be bad in a whole host of ways, not just in how they affect cholesterol levels, and should be minimized or avoided entirely. 

Most sources of mono- and poly- unsaturated fats do contain some amount of saturated fat. Nuts, seeds, some legumes, and foods like olives and avocados (both of which are technically fruits) and their extracted oils, are some examples. Saturated fats from these sources do not seem to affect cholesterol levels or, in some cases, even have an LDL lowering effect. Some evidence shows that poly- and mono- unsaturated fats will upregulate LDL receptors on the liver, pulling them out of circulation, basically the opposite effect of saturated fat. They also typically contain fiber, which has an effect on LDL. I will unpack this in a moment. Olive oil in particular is known to have a whole host of health promoting benefits, from regulating inflammation, blood pressure, blood sugar levels, and cholesterol levels. 

Fiber. It may seem strange that fiber could play a role in saturated fat consumption, but it does, in a bit of a roundabout way. Bile acids are produced by the body to help digest fat. These are typically reabsorbed and recycled after use. However, fiber, in this case soluble fiber, binds to these bile acids causing them to be excreted in feces with the fiber rather than being reabsorbed. These bile acids require cholesterol to be created, so when they are lost in stool, our body has to upregulate their production using circulating cholesterol from the blood, thus lowering the blood cholesterol total. This will therefore have a net effect of offsetting the saturated fat we eat in terms of our LDL level.

Dark chocolate is a plant based source of saturated fat, and this one being particularly concentrated, usually around 50% of the total fat content being saturated. Despite its high saturated fat content, it does not seem to raise risk. (Here I am talking about true dark chocolate, 80% or higher, anything less than that is a glorified candy bar and does not count) This is likely that it comes along with a high amount of fiber, and antioxidants like flavonoids and polyphenols, which have been shown to promote stable blood pressure and decrease cortisol, among a whole host of benefits. Dark chocolate does tend to accumulate heavy metals so this would be a food to include only in modest amounts. Coconut is another plant based saturated fat that seems to have a similar risk profile to dark chocolate. 

Seafood contains some saturated fat, in similar ratios to avocado, olive oil and nuts. Seafood, particularly small low-mercury fatty fish such as wild caught sardines, salmon, herring, mackerel, anchovies, and trout, are about the healthiest protein sources you can eat. Similar to dark chocolate, one does need to be wary of the amount of heavy metals these foods can contain, so I don’t recommend having them for every meal of every day. But they should be in your diet at least 2-3 times per week. They contain high amounts of omega-3, which have a net LDL lowering effect and are fantastic for overall health, not just heart disease risk. 

Animal products. Particularly meats, are the real point of contention here. Many of the observational studies show an increased risk with most animal products, particularly red meat. Most of these studies have huge confounding variables, from healthy user bias, to flaws in research design, like red meat being lumped together in categories with foods like pizza and lasagna in some cases. What are my views here? I want to first state that I include animal products in my diet daily. They are fantastic protein sources. I eat 3-5 eggs every day. I drink 2 cups of whole milk a day and eat copious amounts of greek yogurt. I eat 7-10 oz of venison daily and enjoy a nice steak from time to time. I consume chicken regularly. I have no problem with animal products. Red meat especially is one of the most nutrient dense foods and I think it should be eaten daily. Milk and eggs are fantastic protein sources and come with a whole host of benefits. However, I do think there is nuance here that is worth discussing. I try to consume metas  in the leanest forms I can. If I can get my animal products grass fed/pasture raised I prefer that. 

For a long time, full fat dairy was demonized for its high amount of saturated fat, with some sources having the highest amount of saturated fat of any food group. Cheese in particular is extremely high in saturated fat. Despite this, full fat dairy does not seem to have an effect on heart disease risk, with some sources even having a protective effect. This does not mean you can go out and eat all the cheese and milk you want, remember happy medium. But it does mean you can safely consume it within reason. Butter seems to have different effects for some reason. Most studies seem to show a neutral or slightly increased risk from it. Some theorize this is due to the processing of the butter, where the milk fat globules are broken up during churning and therefore are digested differently. I personally choose to minimize butter consumption, while enjoying as much full fat dairy from other sources as I please. 

Eggs I think are fine to consume to your heart’s content, even the yolk, which is extremely nutrient dense. Eggs were demonized in the past for their high cholesterol content, but we have already put that myth to bed. Lean poultry and red meat I think are great within reason. Pork is pretty hard to find lean and can get very high in not only saturated fat but just calories in general. While I am not convinced by the data regarding animal products being directly harmful, I can see the harm is extremely fatty animal products. First, their caloric content can be hard to determine, which can make controlling calories difficult. Take a ribeye steak for example. Depending on the fat content, which can vary wildly, a standard cut of meat can run anywhere from 600 to over a thousand calories. That’s a huge margin to play with. Someone at a healthy body weight probably may not need to concern themselves as much with this, but that is not most people. I personally like to weigh and track all my food and keep my food intake pretty consistent. These fatty meats are the opposite of consistency, which is why I choose to instead opt for learner cuts of meat and add back in fats from things I can weigh and control such as olive oil, nuts, or avocado. Something else to consider is that it’s a lot easier to add fats than take them away. If the cut of meat already has a ton of fat, you’re kinda stuck with that, unless you want to go in and manually try to trim off what fat you can. It’s a lot more practical to start with the leanest piece of meat you can, and add fats back in a way that you can control. You don’t necessarily need to avoid animal fats when adding fats back in. If you want to add rendered animal fat, be my guest. At the very least, you have more control over the energy density of your meal with this method.

Our modern food system is optimized for metabolically sick animals. They are overfed, often force-fed even, and pumped full of hormones to promote growth, to increase margins. More fat on the animal means more yield. Saturated fat in animal meat can be viewed as a form of empty added calories or of lower food quality. Unfortunately, these animals are not what I would call healthy, and that has to be reflected in the quality of the meat. Most animals in the wild during our hunter-gatherer days would have been exceptionally lean. Never would you have found a cow or pig holding the amount of fat that is typical of a conventionally raised animal today. Bacon or a ribeye steak are basically the fattiest part of an overly fatty animal force fed low quality grains and oils to fatten them up. Foie Gras is the liver of a duck that is force fed to induce fatty liver disease. What is typically the most expensive form of meat you see at the store? Aside from the choice cuts of steak, it’s the 95/5 ground beef, the wild venison, the wild caught seafood; the foods with the highest protein to calorie ratio. Simply compare cuts of chicken. Breast is generally more expensive than thighs or drumsticks. The cheaper stuff has been cheapened by adding excess fat. The expensive foods are expensive because you are literally paying for more protein, more quality. This is why I said I opt for grass fed/pasture raised when I can.These animals are raised in a more traditional way that is healthier for the animal and, in my opinion, contributes to a healthier meat source for us.  They tend to be leaner and have a more optimized nutrient profile. Again, I don’t have a problem with animal fats, per se, just too much of them. Eat your lean animal products. They will come along with a little fat, in the appropriate amounts. 

What is the take away here? Saturated fat is not bad in moderation. It should be included in your diet, just in the appropriate amounts. Mono-unsaturated fats (olive oil and macadamia nuts being my favorites, but lean animal proteins have some as well) and omega-3’s which most people do not get nearly enough of, seem to be the best for overall health and longevity and should be your focus. If you load up on fat from animal meats, where is the room for the olive oil, seafood, nuts, avocado, and for that matter the eggs and dairy, which are far better animal fat sources in comparison. The bulk of your fats should still be coming from monounsaturated fats and you should put a focus on omega-3’s since our modern diet is so devoid of them. Your primary source of saturated fat should be eggs, full fat dairy and a little coming from lean animal meats. Saturated fat is not to be feared, it is simply to be managed.