Is Saturated Fat Still the Villain We Thought?
For decades, saturated fat—found in butter, red meat, and cheese—has been cast as a dietary demon, blamed for clogging arteries and triggering heart attacks. Public health campaigns urged us to swap steak for salads and butter for olive oil, promising longer, healthier lives. Yet, beginning with Dr Atkins in the late 1990s, it started to become clear that the low-fat/high-carbohydrate diet was not the answer for everyone. As heart disease remains the leading cause of death globally, a growing chorus of researchers, doctors, and journalists questions whether saturated fat deserves its reputation as a silent killer. The science, they argue, is less conclusive than we’ve been told, and the answer depends on who you are, what you eat, and how your body responds.
To unravel this debate, I’ll use two sources: experts and metastudies.
The experts
First, let’s look at the views of seven key voices shaping the conversation:
Gary Taubes: the keto warrior
Gary Taubes, author of Good Calories, Bad Calories and The Case for Keto, sees saturated fat as a scapegoat in a misguided war on fat. He argues that carbohydrates, not fats, drive heart disease by spiking insulin, which promotes fat storage and inflammation. “The low-fat mantra failed us,” Taubes told The Guardian in 2021. “Heart disease rates didn’t plummet when we ditched butter for bread.”
Taubes points to historical data and observational studies suggesting no clear link between saturated fat and heart disease. A 2010 American Journal of Clinical Nutrition meta-analysis found no significant association between saturated fat intake and cardiovascular disease (CVD) risk in 350,000 people. He also cites the rise in obesity and diabetes since the 1980s low-fat push as evidence that carbs are the real problem.
Taubes advocates unrestricted saturated fat intake within a ketogenic diet (<50 grams carbs/day), favoring butter, beef, and eggs over processed carbs. He claims this approach cuts CVD risk by 20–30% by reducing insulin-driven inflammation, especially for those with obesity or diabetes. For older adults (60–90), he sees keto as a way to reverse metabolic issues, potentially adding 3–5 years to life.
Critics, including a 2017 Cochrane Review, note that reducing saturated fat to <10% of calories lowers CVD events by 17%. Taubes’ dismissal of LDL cholesterol’s role in heart disease clashes with mainstream cardiology.
Ben Bikman: insulin resistance as the true enemy
Dr Ben Bikman, a biomedical scientist and author of Why We Get Sick, zeroes in on insulin resistance as the root of heart disease. “High insulin levels damage arteries and fuel plaque buildup,” he explained in a 2022 podcast. Keto diets, high in saturated fat but low in carbs, reverse this by keeping insulin low, he says.
Bikman cites studies like a 2021 Journal of Clinical Lipidology trial showing keto diets reduce triglycerides (15–25%) and improve blood sugar (HbA1c drops ~0.7–1.2%), cutting CVD risk factors by 15–20%. He argues saturated fat’s impact on LDL is less concerning in a low-insulin state, pointing to a 2021 American Journal of Clinical Nutrition study showing whole-food saturated fats (e.g., eggs) don’t clearly raise CVD risk.
Bikman supports saturated fat from whole foods (e.g., meat, dairy) within a keto diet, aiming for <50 grams carbs/day. He estimates a 15–25% CVD risk reduction for insulin-resistant people. For older adults, he stresses adequate protein (1.2–1.6 g/kg body weight) to prevent muscle loss, which could indirectly raise CVD risk by 5–10%.
However, a 2023 BMJ meta-analysis linked low-carb, high-fat diets to a 10–15% higher CVD risk over decades, suggesting long-term risks from LDL elevations Bikman downplays.
Peter Attia: precision over dogma
Dr Peter Attia, a physician, author of Outlive, and host of The Peter Attia Drive, once championed keto but now takes a nuanced view. “Keto works for some, but it’s not a one-size-fits-all,” he said in a 2021 podcast. He focuses on individual responses, using advanced lipid tests like apolipoprotein B (apoB) to gauge heart disease risk.
Attia acknowledges keto’s benefits: a 2021 Nutrients trial showed it reduces weight (5–10%) and triglycerides (10–20%), potentially lowering CVD risk by 10–20% in insulin-resistant people. But he warns that 30–50% of keto dieters see LDL spikes, increasing CVD risk by 10–15% if apoB rises (Journal of the American College of Cardiology, 2022). He prefers monounsaturated fats (e.g., olive oil) over saturated fats.
Attia advises limiting saturated fat (<20 grams/day) and monitoring apoB. He supports keto for diabetes or obesity but suggests cycling off after 3–6 months. For older adults, he’s cautious, citing risks of muscle loss and low fiber, which could raise CVD risk by 5–10%. He estimates a neutral to 10% CVD risk reduction with proper management.
Attia is a concierge doctor to billionaires. His reliance on advanced testing may be inaccessible, and long-term keto mortality data are lacking, as noted in a 2018 Lancet Public Health study showing low-carb diets increase mortality by 15–20% over 25 years.
Mark Hyman: A healthier keto diet
Dr Mark Hyman, a functional medicine physician and author of many books on nutrition, views keto as a short-term tool for conditions like diabetes or obesity, not a lifelong diet. “Done right, keto can reset your metabolism,” he wrote in The Pegan Diet. He emphasizes whole foods and a “healthy keto” with low-carb vegetables and nutrient-dense fats.
Hyman cites a 2018 Cleveland Clinic study where keto improved 22 of 26 CVD risk factors, including inflammation (C-reactive protein drops 10–20%) and HDL (5–10% rise), potentially cutting CVD risk by 15–20%. He’s less worried about saturated fat from whole foods like eggs but urges moderation (10–15% of calories) to avoid LDL spikes.
Hyman suggests a cyclical keto (e.g., 5 days on, 2 days off) with olive oil, avocados, and fish over butter or red meat. He estimates a 15–20% CVD risk reduction short-term for metabolic issues. For older adults, he prefers a Mediterranean-style keto to avoid nutrient deficiencies, which could raise CVD risk by 5–10%.
Hyman’s optimism lacks long-term mortality data. A 2023 BMJ study suggests low-carb, high-fat diets increase CVD risk by 10–15% over time, challenging his long-term claims.
Thomas Dayspring: he lipidologist’s warning
Dr Thomas Dayspring, a lipidologist, is laser-focused on apoB, the protein in LDL particles that drives atherosclerosis. “ApoB is the best predictor of heart disease risk,” he told The Peter Attia Drive in 2025. He sees keto’s high saturated fat content as a potential problem, elevating apoB in 30–40% of people.
Dayspring acknowledges keto’s short-term benefits: a 2021 Nutrients trial showed it reduces metabolic syndrome markers by 15–20%, potentially lowering CVD events. But he warns that apoB spikes increase CVD risk by 15–25% (Journal of Clinical Lipidology, 2019), potentially shortening life by 3–5 years. He recommends replacing saturated fats with olive oil or fish.
Dayspring advises capping saturated fat at 10–15% of calories (~20–30 grams/day) and monitoring apoB weekly. He supports keto for insulin resistance but prefers Mediterranean diets for long-term CVD prevention (20–30% risk reduction). For older adults, he’s skeptical, citing risks of sarcopenia and low fiber.
Dayspring’s focus on apoB is evidence-based, but his caution about keto may overlook individual variations where apoB remains stable, as noted in some keto trials.
Mario Kratz: the dairy defender
Dr Mario Kratz, a nutrition researcher in Austria (formerly at the University of Washington), studies dairy fats and their complex effects on health. “Saturated fat isn’t a single villain,” he told Nutrition Reviews in 2020. His work suggests dairy fats (e.g., in cheese, yogurt) may not harm heart health as much as once thought due to their unique fatty acid profiles and nutrient matrix.
Kratz cites a 2021 American Journal of Clinical Nutrition study showing dairy fats don’t significantly raise CVD risk, unlike red meat fats. He argues that foods like yogurt may even lower CVD risk by 5–10% due to probiotics and calcium. However, he agrees with mainstream guidelines that high saturated fat intake (>10% of calories) increases LDL, raising CVD risk by 10–15% (Circulation, 2020).
Kratz supports moderate saturated fat (7–10% of calories) from dairy but advises limiting red meat and tropical oils. He recommends whole-fat yogurt and cheese within a balanced diet, estimating a neutral to 5% CVD risk reduction. For older adults, he sees dairy as a nutrient-dense option to combat frailty, potentially lowering CVD risk indirectly by 5–10%.
Kratz is one of the few keto proponents to acknowledge the risk of eating too much saturated fat. He advocates mixing nuts, avocado, fish, beans, lentils, and tofu into your diet to replace carbs with protein and healthy fats.
Tim Noakes, the saturated fat promoter
Dr. Tim Noakes, an Emeritus Professor at the University of Cape Town and a National Research Foundation A1-rated scientist, has significantly influenced nutrition discourse, particularly through his advocacy for low-carbohydrate, high-fat (LCHF) diets. His views on saturated fat and heart disease challenge conventional dietary guidelines, positioning him as a polarizing figure in medical and nutritional circles.
Noakes’s stance is that saturated fat does not cause heart disease, a view he has expressed in various forums. Noakes argues that excessive carbohydrate consumption, particularly refined sugars and starches, is the primary dietary factor contributing to heart disease. He has published several articles explaining why he believes sugar and carbohydrates are the leading causes of heart disease — via insulin resistance.
The metastudies
Metastudies are critical, because they combine many trials into one view. They are usually done by statisticians and therefore help shed light on which studies are higher quality. Not all metastudies are valuable, but most are. More recent metastudies are better than older metastudies. In general, metastudies before 2016 are not worth spending time on. In most cases, you want metastudies that look at endpoints like heart attacks, stroke, and death, rather than biomarkers like cholesterol or triglycerides in the blood.
One of the problems with any studies of diet and outcomes is that it’s extremely expensive to control all the factors, so researchers generally use epidemiological studies, which are far less reliable. Most metastudies, therefore, concentrate on randomly controlled trials. Here are some of the most recent, in chronological order:
Reduction in saturated fat intake for cardiovascular disease, 2020
Conclusion: Reducing saturated fat intake for at least two years causes a potentially important reduction in combined cardiovascular events. Replacing the energy from saturated fat with polyunsaturated fat or carbohydrate appear to be useful strategies, while effects of replacement with monounsaturated fat are unclear. The reduction in combined cardiovascular events resulting from reducing saturated fat did not alter by study duration, sex or baseline level of cardiovascular risk, but greater reduction in saturated fat caused greater reductions in cardiovascular events.
Saturated Fats and Health: A Reassessment and Proposal for Food-Based Recommendations: JACC State-of-the-Art Review, 2020.
Conclusion: Most recent meta-analyses of randomized trials and observational studies found no beneficial effects of reducing SFA intake on cardiovascular disease (CVD) and total mortality, and instead found protective effects against stroke. Although SFAs increase low-density lipoprotein (LDL) cholesterol, in most individuals, this is not due to increasing levels of small, dense LDL particles, but rather larger LDL particles, which are much less strongly related to CVD risk. It is also apparent that the health effects of foods cannot be predicted by their content in any nutrient group without considering the overall macronutrient distribution. Whole-fat dairy, unprocessed meat, and dark chocolate are SFA-rich foods with a complex matrix that are not associated with increased risk of CVD. The totality of available evidence does not support further limiting the intake of such foods.
Association between dietary fat intake and mortality from all-causes, cardiovascular disease, and cancer: A systematic review and meta-analysis of prospective cohort studies, 2021.
Conclusion: Diets high in saturated fat were associated with higher mortality from all-causes, CVD, and cancer, whereas diets high in polyunsaturated fat were associated with lower mortality from all-causes, CVD, and cancer. Diets high in trans-fat were associated with higher mortality from all-causes and CVD. Diets high in monounsaturated fat were associated with lower all-cause mortality.
Saturated fat: villain and bogeyman in the development of cardiovascular disease?, 2022
Findings from the studies reviewed in this paper indicate that the consumption of SFA is not significantly associated with CVD risk, events, or mortality. Based on the scientific evidence, there is no scientific ground to demonize SFA as a cause of CVD. SFA naturally occurring in nutrient-dense foods can be safely included in the diet. My problem with this study is it may have put too much emphasis on the PREDIMED trial, which in my view was very poorly done.
Red meat consumption, cardiovascular diseases, and diabetes: a systematic review and meta-analysis, 2023
Conclusion: Unprocessed and processed red meat consumption are both associated with higher risk of CVD, CVD subtypes, and diabetes, with a stronger association in western settings but no sex difference.
Saturated Fat Restriction for Cardiovascular Disease Prevention: A Systematic Review and Meta-analysis of Randomized Controlled Trials, 2025.
Conclusion: The findings indicate that a reduction in saturated fats cannot be recommended at present to prevent cardiovascular diseases and mortality.
Dr John Ioannidis from Stanford is one of the leaders of the meta-analysis movement. He teaches medical statistics and how to do good metastudies. While he hasn’t written specifically about saturated fat, it seems likely that Ioannidis would say the evidence linking saturated fat to heart disease is weak and largely based on flawed observational studies. He would call for more rigorous studies before making population-wide recommendations and warn against overconfidence in nutrition guidelines that rest on poor-quality data.
What should you eat?
The results are clear as mud: we have no idea what causes heart disease! And yet, heart disease kills more people than any other. More research is needed!
Still, we have to eat something. What should we eat?
In my view, the first thing we should all do is exercise more. From a diet perspective, the confusion could very likely come from the fact that researchers don’t take insulin resistance into account when they run trials, so that confusion makes its way through the system. I’m not a doctor, I’m not a professional researcher, so your reading of the above evidence may differ from mine, but here’s how I would summarize:
Processed meats are probably not ideal. Processed meats — hot dogs, salami, anything that comes in a can — probably aren’t as healthy as cooking fresh meat. I think all the experts would agree we should limit those to just treats, rather than part of a good diet.
For People with Insulin Resistance or Type 2 Diabetes: Maintain ketosis and watch your ApoB number. If it’s too high, reduce red meat and focus more on chicken, turkey, fish, beans, lentils, and tofu. Get plenty of fiber and fresh foods.
For Older Adults (60–90): Eat to modify your A1c number first. Below 5.9, you don’t need to be in ketosis, but you should limit sugars and carbohydrates until you’re under 5.7. Focus on getting enough protein — the older you are, the more protein you need. This population should eat between .8 and 1 gram of protein per pound of ideal body weight per day. Limit simple carbohydrates to once or twice a month. Get plenty of fiber and fresh foods.
For athletes: Carbs are critical. Most athletes should get 0.8 grams of protein per pound per day and use carbs to fuel your muscles. Don’t let your A1c number go above 5.6 — if it does, lower your glycemic load.
For vegetarians: Hyman’s cyclical, plant-rich keto and Kratz’s dairy-moderated diet align with your goals. Keep your A1c under 5.7 first. Use whey protein to help get enough and support muscle growth. Take some B vitamins to add insurance. And get plenty of fiber and fresh foods.
For vegans: veganism is not a healthy diet. I say that as someone who was vegan for 45 years and wrote one book on the benefits of being vegan. I plan to write more about what I have learned. If you care about your health, choose another option.
For people on a carnivore diet: We know almost nothing about this. Because it keeps people in ketosis, it’s good for losing weight. Is it a good long-term diet? My answer is that if your ApoB stays under 120, it might be, but by eliminating fiber from your diet, you’re going far outside the boundaries of what most scientists believe is healthy. You may not die of heart disease, but you may get cancer. You may also want to watch other factors, like iron, calcium, etc. Could you live on a carnivore diet and just take lots of cholesterol-lowering drugs? Who knows? No one knows the answer to that question.
Saturated fat doesn’t seem to be a universal villain, but it’s not yet clear that it’s harmless. Neither a fully plant-based nor a fully meat-based diet will support optimal health, but there are many good choices in between. In my view, your A1c number will tell you what you can and can’t eat, and your ApoB number will tell you how much saturated fat you should tolerate. Perhaps in another ten years, we’ll know more, but for the moment, we need to read the evidence critically and keep our minds open to the idea that we simply don’t know as much as we would like to know about saturated fats and heart disease.
Want to lose weight? Come to my weight-loss page.
Want to live 10-20 years longer? Learn the facts.