What’s the Deal With Saturated Fat on Keto?
Many people are left completely confused on the topic of dietary fat, especially when it comes to the notorious saturated fat. The low-fat craze seems to be waning, but the fog of confusion persists. You know you’re supposed to consume relatively high amounts of healthy fats on a ketogenic diet, but what about saturated fat? Is saturated fat a good idea to consume on keto? What foods contain saturated fat? What about the connection to heart disease or obesity? Let’s delve into this hot topic that’s still somewhat coated in controversy.
What Is Saturated Fat?
Food contains three macronutrients: protein, carbs, and fat. Contrary to popular belief, you need protein and fat to survive, but you don’t need glucose (sugar). Your body can create its own glucose from dietary fat and protein in a process called gluconeogenesis.
Your body can’t make essential amino or fatty acids, so you must obtain them from your diet. There are no essential carbohydrates, but there are essential fatty acids and proteins. [1] This doesn’t mean that carbohydrates can’t be a healthy part of your diet; it’s just an important fact to remember.
Protein and carbohydrates yield four calories per gram, whereas fat yields nine calories per gram. This means that fat provides lots of energy and leaves you feeling satiated. Fats are composed of greater amounts of oxygen, carbon, and hydrogen. Saturated fat is a type of fatty acid that’s saturated with hydrogen atoms. For every carbon atom in saturated fat, there are two hydrogen atoms.
Monounsaturated fats contain one double bond between two connecting carbon atoms. Polyunsaturated fats have two or more double bonds between connecting carbon atoms with carbon atoms on the same side of the double bond. Trans fats have double bonds, but the hydrogen atoms are on the opposite sides of the double bonds.
All this science talk about carbon atoms and double bonds can fly over your head, but the main point to know is that saturated fat is simply more ‘saturated’ with hydrogen atoms than unsaturated fats.
Saturated fats tend to be solid at room temperature and are found in meat, dairy, fish, and coconut oil. Coconut oil has a whopping 87% saturated fat. Monounsaturated fats and polyunsaturated fats are found in foods like olive oil and fatty fish.
Trans Fats
The main fats to avoid are trans fats, which are rarely found in nature. Trans fats are largely found in partially hydrogenated oils, such as canola oil. They’re typically created during industrial manufacturing processes using a combination of heat and chemicals like hexane. Sadly, many restaurants reuse and reheat canola oil, particularly when making fries and fried foods. Strong research has associated trans fats with a heightened risk of heart disease and negative effects on cholesterol levels.
The Benefits of Saturated Fat
Health and media organizations have demonized saturated fat, but it turns out this naturally occurring fat is also essential, and not getting enough can be detrimental. Before we look at the demonization of saturated fat, let’s examine the benefits.
Saturated fat assists numerous bodily functions, from hormone production and immune health to neural activity and brain development. [2] [3] Without enough dietary fat, your body can’t make cholesterol or reproductive hormones. This means that if you aren’t consuming enough fat, it could negatively affect fertility and hormonal balance.
All the cells in your body are covered in fatty cell membranes. This membrane is comprised of glycolipids, cholesterol, and phospholipids. Phospholipids make up the bulk of the membrane, and they’re comprised of saturated and unsaturated fatty acids, a phosphate group, and a glycerol group. So, the notorious saturated fat actually helps you build your cells!
Your brain is around 60% fat and needs fat to function properly. You also need fats to absorb crucial fat-soluble vitamins, namely vitamins A, D, E, and K.
The Demonization of Saturated Fat
Some health experts and advocates tell you to avoid coconut oil and meat due to the saturated fat content. Other health experts and advocates tell you to include this natural healthy fat in your ketogenic diet. Why was fat demonized, and why did the controversy arise?
Saturated fat started gaining a bad rep starting in the 1950s and was largely fueled by a public health scientist called Ancel Keys. Most of Ancel Keys’s studies were observational, and some were clinical. Keys and his wife were proponents of the Mediterranean diet, which has been associated with a range of health benefits, including a reduced risk of developing chronic diseases.
Keys studied Minnesota businessmen looking for a correlation between cholesterol levels and cardiovascular disease and claimed he found associations between the average serum cholesterol and per capita intake of saturated fats and the rate of cardiovascular (heart) disease in the population.
In 1958, Keys started the Seven Countries Study, where he traveled to various countries and noted that heart disease rates drastically varied, with places like Japan having lower rates than Finland. He realized the Japanese diet was usually lower in fat, especially saturated fat, and he also noted that farmers in Finland buttered their cheese.
Insurance companies, physicians, food industry groups, and many others used these ambiguous studies to continue the demonization of saturated fat.
Ancel Keys’ Seven Countries Study originally included more nations, which sparked accusations of cherry-picking data to obtain the desired result that saturated fat is the ‘bad egg.’ In the same graph that Keys used to implicate saturated fat, a valid link between sugar and heart disease could also be implicated. The countries eating more fat were also eating more sugar.
Scientists pointed to sugar and raised questions and concerns that these associations weren’t conclusive, and that more clinical and laboratory research was necessary before safely making dietary recommendations. Some of Ancel Key’s projects and studies were supposed to be published but were found hidden in dusty basements for decades. [4]
During this time, as governments around the world began recommending the population lower their intake of all fats, and particularly saturated fat, the sugar industry allegedly paid scientists to downplay the link between heart disease and sugar. Like the tobacco industry, the sugar industry funded questionable science.
For many, the jury is still out on saturated fat, but for others, fat has been exonerated anecdotally and in the scientific literature. The interesting documentary Fat Fiction examines the history of the science of saturated fat.
Mounting research to date shows that saturated fat isn’t the artery-clogging fat linked to heart disease; rather, heart disease is more complex than ‘bad fat in a clogged drainpipe.’ Inflammation, infection, and sugar are still being studied and considered as causal factors for heart disease.
The science is far from settled, and more research is always ongoing, but it’s clear that science can be manipulated and head off in the wrong direction, leaving many of us blindly following suit.
The Fatty Conclusion
In addition to the overwhelming studies on the health benefits of natural saturated fat and the questionable science and manipulated observational studies of Ancel Keys, here are some points to consider the next time you think about pushing away that plate of grass-fed steak, eggs, or those delicious coconut oil-filled chocolate fat bombs:
- The Mediterranean diet usually limits saturated fat and meat intake and encourages fish. However, this doesn’t entirely make sense when you realize that the fatty fish mackerel, a favorite on the Mediterranean diet, provides more saturated fat than a T-bone steak. It became the ‘in’ thing to ‘watch your saturated fat intake’, but it’s more hype than hip and more talk and frenzy than solid scientific evidence.
- A 1981 study of the Tokelau island chain population in the South Pacific concluded that although over 60% of their calories came from coconuts, which have higher amounts of saturated fat, the population had good overall health and surprisingly low rates of heart disease. [5] Studies show coconut oil combined with exercise could lower and normalize blood pressure and improve cholesterol. [6] One study comparing soybean oil to coconut oil revealed that coconut oil actually reduced total and LDL cholesterol while increasing HDL, which is believed to be the good kind of cholesterol. [7] Research also highlights that decreasing saturated fat intake doesn’t decrease the risk of developing cardiovascular disease. [8] Even animal studies correlating a high-fat diet with obesity also used a diet high in carbohydrates, skewing the results. We know eating lots of carbohydrates spikes insulin production, which is the fat-storage hormone.
- The polyunsaturated fats in vegetable oil and canola oil can’t retain their structure when heated to higher temperatures. However, saturated fats found in duck fat, lard, coconut oil, and tallow retain their molecular structure and remain completely safe for consumption under high heat.
Many people are left wondering: how could a natural food (like meat) that people have been eating for millions of years suddenly be the cause of modern diseases like heart disease and obesity? At the same time, humans haven’t been consuming highly processed and refined carbs, sugars, chemical additives for millions of years.
References
Westman, E. C. (2002). Is dietary carbohydrate essential for human nutrition? American Journal of Clinical Nutrition, https://doi.org/10.1093/ajcn/75.5.951a
Gerhsuni, V. M. (2018). Saturated fat: Part of a healthy diet. Current Nutrition Reports, 7(3), 85-96. DOI: 10.1007/s13668-018-0238-x
Astrup, A., Magkos, F., Bier, D. M., Brenna, J. T., Otto, M. C. O… Krauss, R. M. (2020). Saturated fats and health: A reassessment and proposal for food-based recommendations: JACC state-of-the-art review. J Am Coll Cardiol, DOI: 10.1016/j.jacc.2020.05.077
Kearns, C. E., Schmidt, L. A., & Glantz, S. A. (2016). Sugar industry and coronary heart disease research: A historical analysis of internal industry documents. JAMA, 176(11), 1680-1685. DOI:10.1001/jamainternmed.2016.5394
Prior, I. A., Davidson, F., Salmond, C. E., & Czochanska, Z. (1981). Cholesterol, coconuts, and diet on Polynesian atolls: A natural experiment: The Pukapuka and Tokelau Island Studies. American Journal of Clinical Nutrition, 34(8), 1552-1561. DOI: 10.1093/ajcn/34.8.1552
Turchiano, R. (2015). Beating high blood pressure with a combination of coconut oil and physical exercise. Canadian Science Publishing, https://clinicalnews.org/2015/02/10/beating-high-blood-pressure-with-a-combination-of-coconut-oil-and-physical-exercise/
Khaw, K-T., Sharp, S. J., Finikarides, L., Afzal, I., Lentjes, M., Luben, R., & Forouhi, N. G. (2018). Randomised trial of coconut oil, olive oil or butter on blood lipids and other cardiovascular risk factors in healthy men and women. BMJ Open, 8(3), e020167. DOI: 10.1136/bmjopen-2017-020167
Chowdhury, R., Warnakula, S., Kunutsor, S., Crowe, F., Ward, H. A., Johnson, L., Franco, O. H., Butterworth, A. S., Forouhi, N. G., Thompson, S. G., Khaw, K. T., Mozaffarian, D., Danesh, J., & Di Angelantonio, E. (2014). Association of dietary, circulating, and supplement fatty acids with coronary risk: a systematic review and meta-analysis. Annals of internal medicine, 160(6), 398–406. https://doi.org/10.7326/M13-1788
