Fats

Fats are made of smaller parts called fatty acids, and different types of fatty acids act a bit differently in your body. Some are better to eat more often, and others are best to keep in check.​

What fatty acids are

  • Fatty acids are the “building blocks” of fat in food and in your body, and they can be used for energy.​

  • They are like chains made mostly of carbon and hydrogen; small changes in the chain create different kinds of fat (saturated, monounsaturated, polyunsaturated).​

Saturated fats

  • Saturated fats have straight chains and no “bends,” so they tend to be solid at room temperature, like butter or the fat on steak.​

  • Eating saturated fat is good for you and is very satiating which tends to make you feel full for a longer period of time. They cannot be oxidized and thus, do not lead to inflammation.​

Monounsaturated fats

  • Monounsaturated fats (often called MUFAs) have one bend in the chain, so they are usually liquid, like olive or canola oil.​

  • When they replace polyunsaturated fat in your diet, they tend to help improve cholesterol numbers and may be better for your heart.​ They have only one double bond and can only oxidize once.

Polyunsaturated fats

  • Polyunsaturated fats (PUFAs) have two or more double bonds in the chain and are found in things like seed oils, walnuts, and fatty fish.​

  • Thes fats can be good or bad for you based on where the first double bond is. Omega-3 fatty acids are healthy (although recent research has shown too much can lead to the risk of atrial fibrillation). Omega-6 fatty acids tend to oxidize and cause inflammation. They aslo act on your body’s “endocannabinoid system” like THC from marijuana to drive hunger.​

Omega‑6 vs. omega‑3

  • Omega‑6 and omega‑3 are two “families” of polyunsaturated fats that your body cannot make on its own, so you have to get them from food.​

  • Omega‑6 fats come mostly from common vegetable oils (like soybean and corn oil) and many packaged foods, while omega‑3 fats come from fatty fish (like salmon) and some plants like flax and chia.​

Why the balance matters

  • Omega‑6 fats can be used to make substances that can turn on inflammation, and omega‑3 fats can help calm inflammation and support heart and brain health.​

  • Modern diets often have lots of omega‑6 and not enough omega‑3, so aiming to eat fish regularly and including foods like flax, chia, or walnuts can help even things out.​ It is logical to cut down the omega-6 fatty acids to maintain the proper ratios of the two for optimal health.

  • There is also Alpha Linolenic Acid which is an essential fatty acid (the body does not make it) Only 1.1 grams for females and 1.6 grams for males are needed to meet the reccomended dietary amounts per day. That is the equivalent of 1/4 tablespoon of flax seed oil or seven whole walnuts. It is present in only small amounts in animal meat and is most abundant in flax seeds, chia seeds and walnuts. The megafauna animals of our ancestors had plenty of it in their meat, but today’s meat does not.

Simple food guidelines

  • Try to use more saturated fats or oils like olive or avocado instead of seed oils (vegetable oils).​

  • Eat fish (especially fatty fish) a couple of times per week and include some walnuts and chia seeds to boost healthy omega‑3 and alpha linolenic acids.​

Why have we been told saturated fats are bad for us?

Saturated fats have been demonized since Ansel Keys came out with his 7 Country Study. From this came the “Diet Heart Hypothesis” which espouses that saturated fat raises cholesterol which leads to heart disease. This theory was adopted by the first governmental dietary recommendation panel and led to the “Food Pyramid” and the recommendation to eat a low saturated fat, medium protein, high carbohydrate diet. It can be demonstrated that the 6 Country Study was highly flawed and it was not reproducible. Keys actually had data from 22 countries but cherry picked six countries that aligned with his theory and ignored the rest.

Two other studies were conducted to “verify” the Six Country study - The Minnesota Coronary Event study and the Sydney Diet Heart Study. Neither could support that saturated fats were bad for us and failed to support the diet heart hypothesis:

  • The data from the Minnesota Coronary Experiment (also called the Minnesota Coronary Survey) was discovered decades later in unlabeled boxes in the basement of principal investigator Ivan Frantz’s home, containing old magnetic tapes and paper records that allowed a full reanalysis.​

  • The Sydney Diet Heart Study’s data was also “lost” for many years and later recovered from obsolete computer tapes

Both studies were re-evaluated. In the Re-evaluation of the traditional diet-heart hypothesis: analysis of recovered data from Minnesota Coronary Experiment (1968-73), the conclusion was:

“Available evidence from randomized controlled trials shows that replacement of saturated fat in the diet with linoleic acid [an Omega-6 polyunsaturated fat] effectively lowers serum cholesterol but does not support the hypothesis that this translates to a lower risk of death from coronary heart disease or all causes. Findings from the Minnesota Coronary Experiment add to growing evidence that incomplete publication has contributed to overestimation of the benefits of replacing saturated fat with vegetable oils rich in linoleic acid.”

In the the following study: Use of dietary linoleic acid for secondary prevention of coronary heart disease and death: evaluation of recovered data from the Sydney Diet Heart Study and updated meta-analysis, the conclusions were:

  • The re-evaluation concluded that substituting linoleic acid for saturated fat in this post‑MI male cohort increased all‑cause mortality, coronary heart disease mortality, and cardiovascular mortality, rather than reducing them.​

  • The authors further concluded that, when these recovered data are incorporated into a meta‑analysis of similar linoleic‑acid–only trials, there is no clear evidence of cardiovascular benefit and possible signal of harm, so advice to increase omega‑6 linoleic acid alone in place of saturated fat warrants reconsideration.

Thus, with a flawed study by Ansel Keys, and two major studies hidden for decades, Ansel Keys made his way on to Senator McGovern’s committee on establishing dietary guidelines for the country in 1978. Keys was know as a bully and quite the intimidator of those who opposed his views. There was a British physiologist, John Yudkin, who was the main scientific proponent arguing that sugar—not saturated fat—was the key dietary cause of heart disease. His work (summarized later in his book “Pure, White and Deadly”) directly challenged Ansel Keys’ fat‑centric diet–heart hypothesis by proposing that dietary sucrose was a major driver of cardiovascular disease.​ However, Keys publicly bullied him and his theory lost to the saturated fat theory of heart disease.

  • Internal documents and later historical analyses indicated that the sugar industry actively worked to downplay evidence linking sucrose to heart disease while promoting saturated fat and cholesterol as the primary culprits.​

  • This industry influence, combined with the dominance of Keys’ lipid hypothesis in professional societies and guidelines, led to Yudkin’s sugar-focused hypothesis being marginalized in mainstream cardiology and public health at the time.​

Thus, the food pyramid was born in 1980 telling Americans to cut down on saturated fat and eat mostly carbs. Americans have become one of the most obese and sickest peoples in the world. The standard american diet includes tons of carbs and very little saturated fat, tons of inflammatory seed oils and a lot of processed foods. We should be eating mostly saturated fats, some protein and only a little seed oils (Omega-6 farry acids).

Research showing saturated fat does not cause atherosclerosis or heart disease

Grasgruber, Pavel, et al. “Food Consumption and the Actual Statistics of Cardiovascular Diseases: An Epidemiological Comparison of 42 European Countries.” Food & Nutrition Research, vol. 60, no. 0, 2016, p. 31694, doi:10.3402/fnr.v60.31694.

  • Conclusion “Our results do not support the association between CVDs and saturated fat, which is still contained in official dietary guidelines. Instead, they agree with data accumulated from recent studies that link CVD risk with the high glycaemic index/load of carbohydrate-based diets. In the absence of any scientific evidence connecting saturated fat with CVDs, these findings show that current dietary recommendations regarding CVDs should be seriously reconsidered.”

Ramsden, Christopher E., et al. “Re-Evaluation of the Traditional Diet-Heart Hypothesis: Analysis of Recovered Data from Minnesota Coronary Experiment (1968-73).” BMJ, vol. 353, 2016, p. i1246, doi:10.1136/bmj.i1246.

  • Conclusions “Available evidence from randomized controlled trials shows that replacement of saturated fat in the diet with linoleic acid effectively lowers serum cholesterol but does not support the hypothesis that this translates to a lower risk of death from coronary heart disease or all causes. Findings from the Minnesota Coronary Experiment add to growing evidence that incomplete publication has contributed to overestimation of the benefits of replacing saturated fat with vegetable oils rich in linoleic acid.”

Ramsden, Christopher E., et al. “Use of Dietary Linoleic Acid for Secondary Prevention of Coronary Heart Disease and Death: Evaluation of Recovered Data from the Sydney Diet Heart Study and Updated Meta-Analysis.” BMJ : British Medical Journal, vol. 346, no. feb04 3, 2013, p. e8707, doi:10.1136/bmj.e8707.

  • Conclusions “Advice to substitute polyunsaturated fats for saturated fats is a key component of worldwide dietary guidelines for coronary heart disease risk reduction. However, clinical benefits of the most abundant polyunsaturated fatty acid, omega 6 linoleic acid, have not been established. In this cohort, substituting dietary linoleic acid in place of saturated fats increased the rates of death from all causes, coronary heart disease, and cardiovascular disease. An updated meta-analysis of linoleic acid intervention trials showed no evidence of cardiovascular benefit. These findings could have important implications for worldwide dietary advice to substitute omega 6 linoleic acid, or polyunsaturated fats in general, for saturated fats.”

Wise, Jacqui. “Evidence Does Not Support Guidelines on Saturated Fat, Researchers Say.” BMJ : British Medical Journal, vol. 348, no. mar19 5, 2014, p. g2238, doi:10.1136/bmj.g2238.

  • “The systematic review and meta-analysis, published in the Annals of Internal Medicine, included studies involving more than 600 000 people in 18 countries. The researchers found no association between total saturated fatty acid consumption and coronary risk when they analysed 32 observational studies of fatty acids in dietary intake and 17 observational studies of fatty acid biomarkers.”

You, Wenpeng, et al. “Total Meat Intake Is Associated with Life Expectancy: A Cross-Sectional Data Analysis of 175 Contemporary Populations.” International Journal of General Medicine, vol. 15, 2022, pp. 1833–51, doi:10.2147/ijgm.s333004.

  • Across countries, higher total meat availability correlates with higher life expectancy and lower child mortality, and these associations persist after adjustment for key covariates in regression models."

Astrup, Arne, et al. “Dietary Saturated Fats and Health: Are the U.S. Guidelines Evidence-Based?” Nutrients, vol. 13, no. 10, 2021, p. 3305, doi:10.3390/nu13103305.

  • “The last decade has seen nearly 20 papers reviewing the totality of the data on saturated fats and cardiovascular outcomes, which, altogether, have demonstrated a lack of rigorous evidence to support continued recommendations either to limit the consumption of saturated fatty acids or to replace them with polyunsaturated fatty acids. These papers were unfortunately not considered by the process leading to the most recent U.S. Dietary Guidelines for Americans, the country’s national nutrition policy, which recently reconfirmed its recommendation to limit saturated fats to 10% or less of total energy intake, based on insufficient and inconsistent evidence.”

Siri-Tarino, Patty W., et al. “Meta-Analysis of Prospective Cohort Studies Evaluating the Association of Saturated Fat with Cardiovascular Disease.” The American Journal of Clinical Nutrition, vol. 91, no. 3, 2010, pp. 535–46, doi:10.3945/ajcn.2009.27725.

Ravnskov, Uffe. “A Hypothesis Out-of-Date The Diet–Heart Idea.” Journal of Clinical Epidemiology, vol. 55, no. 11, 2002, pp. 1057–63, doi:10.1016/s0895-4356(02)00504-8.

  • “A meta-analysis of prospective epidemiologic studies showed that there is no significant evidence for concluding that dietary saturated fat is associated with an increased risk of CHD or CVD.”

Malhotra, Aseem, et al. “Saturated Fat Does Not Clog the Arteries: Coronary Heart Disease Is a Chronic Inflammatory Condition, the Risk of Which Can Be Effectively Reduced from Healthy Lifestyle Interventions.” British Journal of Sports Medicine, vol. 51, no. 15, 2017, p. 1111, doi:10.1136/bjsports-2016-097285.

  • “It is time to shift the public health message in the prevention and treatment of coronary artery disease away from measuring serum lipids and reducing dietary saturated fat. Coronary artery disease is a chronic inflammatory disease…”

Howard, Barbara V., et al. “Low-Fat Dietary Pattern and Risk of Cardiovascular Disease: The Women’s Health Initiative Randomized Controlled Dietary Modification Trial.” JAMA, vol. 295, no. 6, 2006, pp. 655–66, doi:10.1001/jama.295.6.655.

  • “Conclusions Over a mean of 8.1 years, a dietary intervention that reduced total fat intake and increased intakes of vegetables, fruits, and grains did not significantly reduce the risk of CHD, stroke, or CVD in postmenopausal women and achieved only modest effects on CVD risk factors, suggesting that more focused diet and lifestyleinterventions may be needed to improve risk factors and reduce CVD risk.”

Lee, Joyce H., et al. “United States Dietary Trends Since 1800: Lack of Association Between Saturated Fatty Acid Consumption and Non-Communicable Diseases.” Frontiers in Nutrition, vol. 8, 2022, p. 748847, doi:10.3389/fnut.2021.748847.

  • “Conclusions: As observed from the food availability data, processed and ultra-processed foods dramatically increased over the past two centuries, especially sugar, white flour, white rice, vegetable oils, and ready-to-eat meals. These changes paralleled the rising incidence of NCDs [Non-Comminicable Diseases], while animal fat consumption was inversely correlated.

Yamada, Satoru, et al. “Saturated Fat Restriction for Cardiovascular Disease Prevention: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.” JMA Journal, vol. 8, no. 2, 2025, pp. 395–407, doi:10.31662/jmaj.2024-0324.

  • Conclusions: The findings indicate that a reduction in saturated fats cannot be recommended at present to prevent cardiovascular diseases and mortality.

Associations of fats and carbohydrate intake with cardiovascular disease and mortality in 18 countries from five continents (PURE): a prospective cohort study. Dehghan, MahshidDiaz, R et al. The Lancet, Volume 390, Issue 10107, 2050 - 2062

  • “High carbohydrate intake was associated with higher risk of total mortality, whereas total fat and individual types of fat were related to lower total mortality. Total fat and types of fat were not associated with cardiovascular disease, myocardial infarction, or cardiovascular disease mortality, whereas saturated fat had an inverse association with stroke. Global dietary guidelines should be reconsidered in light of these findings.”

The Truth About Saturated Fats

The evidence and research, from the time the Diet Heart Hypothesis was developed, has clearly shown that saturated fat is absolutely fine to eat and that polyunsaturated fats (the Omega-6 fatty acids, such as linoleic acid) found in seed oils are the fats that are bad for you. Yes, seed oils will lower LDL. However, LDL does not cause cardiovascular disease (see my page on cholesterol).

Most doctors and nutritionists still follow the “Diet Heart Hypothesis”. I am a doctor and the amount of time spent on nutrition in medical school is very limited. Anything taught to us must follow the US government guidelines. See the research articles provided to see that the government guidelines need to be re-evaluated and that saturated fats are good for you. It is carbohydrates and polyunsaturated fats in excess amounts that are harming us.

Chowdhury R, Warnakula S, Setor Kunutsor S, Crowe F, Ward H, Johnson L et al. Association of dietary, circulating, and supplement fatty acids with coronary risk: a systematic review and meta-analysis. Ann Intern Med 2014;160:398-406.

“The systematic review and meta-analysis, published in the Annals of Internal Medicine, included studies involving more than 600 000 people in 18 countries. The researchers found no association between total saturated fatty acid consumption and coronary risk when they analysed 32 observational studies of fatty acids in dietary intake and 17 observational studies of fatty acid biomarkers. However, total intake of trans fats, found in some processed foods, was associated with coronary disease risk. The researchers, led by Rajiv Chowdhury from the University of Cambridge, also found that higher intake of polyunsaturated fats did not offer any protection against heart disease. They found some evidence that circulating levels of two main types of long chain omega 3 polyunsaturated fatty acids and arachidonic acid are each associated with lower coronary risk. However, their meta-analysis of 27 randomised trialsinvolving more than 100 000 participantsindicated that taking supplements with these nutrients did not significantly reduce the risk of poor coronary outcomes.”


Siri-Tarino PW, Sun Q, Hu FB, et al. Meta-analysis of prospective cohort studies evaluating the association of saturated fat with cardiovascular disease. Am. J. Clin. Nutr. 2010;91(3):535–546.

“During 5–23 y of follow-up of 347,747 subjects, 11,006 developed CHD or stroke. Intake of saturated fat was not associated with an increased risk of CHD, stroke, or CVD, A meta-analysis of prospective epidemiologic studies showed that there is no significant evidence for concluding that dietary saturated fat is associated with an increased risk of CHD or CVD. More data are needed to elucidate whether CVD risks are likely to be influenced by the specific nutrients used to replace saturated fat.”


Ravnskov U. A hypothesis out-of-date The diet–heart idea. J. Clin. Epidemiology. 2002;55(11):1057–1063.

“A large number of scientific studies contradict the hypothesis that dietary fat and high cholesterol play a major role in the causation of atherosclerosis and cardiovascular disease. Readers may probably object that I have preferably picked contradictory studies out of a huge number of supportive ones. However, a thorough examination of the literature in this area [1] has convinced me that most studies are either useless for determining causality, or they are contradictory. But even if many studies were supportive, a valid hypothesis should withstand all attempts of falsification. One single study that falsifies it and which is based on verifiable observations should suffice for its rejection. There are many, more or less probable, alternative hypotheses about the causation of atherosclerosis and cardiovascular disease, but the maintenance of the diet–heart hypothesis by prestigious and powerful scientists and organizations retard their exploration by turning away intellectual and financial resources. Worse is the fact, that any new discovery is twisted and bent to tally with the current concept, not to mention the negative effects on public health, food production, and the health and general well-being of millions of people. It would be a great contribution to science and mankind if influential institutions could break the vicious cycle by supporting researchers who create hypotheses that fit their data, instead of researchers who interpret their data to fit a predetermined hypothesis.”


Malhotra A, Redberg RF, Meier P. Saturated fat does not clog the arteries: coronary heart disease is a chronic inflammatory condition, the risk of which can be effectively reduced from healthy lifestyle interventions. Br. J. Sports Med. 2017;51(15):1111.

“Coronary artery disease pathogenesis and treatment urgently requires a paradigm shift. Despite popular belief among doctors and the public, the conceptual model of dietary saturated fat clogging a pipe is just plain wrong. A landmark systematic review and meta-analysis of observational studies showed no association between saturated fat consumption and (1) all-cause mortality, (2) coronary heart disease (CHD), (3) CHD mortality, (4) ischaemic stroke or (5) type 2 diabetes in healthy adults.1 Similarly in the secondary prevention of CHD there is no benefit from reduced fat, including saturated fat, on myocardial infarction, cardiovascular or all-cause mortality.2 It is instructive to note that in an angiographic study of postmenopausal women with CHD, greater intake of saturated fat was associated with less progression of atherosclerosis whereas carbohydrate and polyunsaturated fat intake were associated with greater progression.”


1.Lee JH, Duster M, Roberts T, et al. United States Dietary Trends Since 1800: Lack of Association Between Saturated Fatty Acid Consumption and Non-communicable Diseases. Front. Nutr. 2022;8:748847.

“Processed and ultra-processed foods increased from <5 to >60% of foods. Large increases occurred for sugar, white and whole wheat flour, rice, poultry, eggs, vegetable oils, dairy products, and fresh vegetables. Saturated fats from animal sources declined while polyunsaturated fats from vegetable oils rose. Non-communicable diseases (NCDs) rose over the twentieth century in parallel with increased consumption of processed foods, including sugar, refined flour and rice, and vegetable oils. Saturated fats from animal sources were inversely correlated with the prevalence of NCDs. Conclusions: As observed from the food availability data, processed and ultra-processed foods dramatically increased over the past two centuries, especially sugar, white flour, white rice, vegetable oils, and ready-to-eat meals. These changes paralleled the rising incidence of NCDs, while animal fat consumption was inversely correlated.”


1.Howard BV, Horn LV, Hsia J, et al. Low-Fat Dietary Pattern and Risk of Cardiovascular Disease: The Women’s Health Initiative Randomized Controlled Dietary Modification Trial. JAMA. 2006;295(6):655–666.

“Over a mean of 8.1 years, a dietary intervention that reduced total fat intake and increased intakes of vegetables, fruits, and grains did not significantly reduce the risk of CHD, stroke, or CVD in postmenopausal women and achieved only modest effects on CVD risk factors, suggesting that more focused diet and lifestyle interventions may be needed to improve risk factors and reduce CVD risk.”


Grasgruber P, Sebera M, Hrazdira E, et al. Food consumption and the actual statistics of cardiovascular diseases: an epidemiological comparison of 42 European countries. Food Nutr. Res. 2016;60(0):31694.

“The most significant dietary correlate of low CVD risk was high total fat and animal protein consumption.” “Our results do not support the association between CVDs and saturated fat, which is still contained in official dietary guidelines. Instead, they agree with data accumulated from recent studies that link CVD risk with the high glycaemic index/load of carbohydrate-based diets. In the absence of any scientific evidence connecting saturated fat with CVDs, these findings show that current dietary recommendations regarding CVDs should be seriously reconsidered.

Astrup A, Teicholz N, Magkos F, et al. Dietary Saturated Fats and Health: Are the U.S. Guidelines Evidence-Based? Nutrients. 2021;13(10):3305.

“Multiple reviews of the evidence have demonstrated that a recommendation to limit consumption of saturated fats to no more than 10% of total calories is not supported by rigorous scientific studies. Importantly, neither this guideline, nor that for replacing saturated fats with polyunsaturated fats, considers the central issue of the health effects of differing food sources of these fats. The 2020 DGAC review that recommends continuing these recommendations has, in our view, not met the standard of “the preponderance of the evidence” for this decision.”