I have not intentionally been sending you fewer blog posts in the past few months, promise. Gosh I hope you noticed…! What I have been doing is analyzing a ridiculous amount of data to compile a comprehensive research paper regarding saturated fat and heart disease. I’m not ready to spill the beans on the finished product just yet, but I’m excited to give you a little glimpse of my findings so far.
I know saturated fat has gotten raked over the coals in the mainstream for decades due to being “artery clogging.” However, the recommendation to eat a “low-fat diet” or “low-saturated-fat diet” is based on some seriously flawed research stemming from the 1960s and 1970s. Which, I have to say, after having utilized technological resources to help me thumb through >500 studies for this project, I have no idea how those researchers were able to truly conduct quality studies. But anyway…
Way back in the 1960s a fella named Ancel Keys led a revolution regarding saturated fat. He found in his infamous Seven Countries Study1 (and derivatives of it) that people who ate the most saturated fat died quicker than those who ate less saturated fat. However, these (Seven Countries and its follow-ons) studies were observational in design (click here for more on why that would matter), and cannot prove cause and effect. Furthermore, one huge (or would have been huge) review analyzed >3,500 studies only to find that ZERO studies exist (as of 2011) to support the recommendation to consume a “low-fat diet” for prevention or treatment of high cholesterol.2 No, that wasn’t a typo: ZERO studies support that. But gosh, the American Heart Association (AHA) is so adamant about low-fat eating! Here is something else super interesting. The Presidential Advisory from the AHA3 that came out in 2017 to reassure everyone that saturated fat (including coconut oil) is still bad for us was a pretty shady publication. By study design criteria, that publication is a narrative review, which means that it has the potential to carry a lot of people’s opinions. No information was listed regarding how they chose studies for their review, which often means that they can selectively include/exclude studies that meet their agenda (this is cutely referred to as “cherry picking data”). Furthermore, it would take me all day to type up all of the financial support the authors received from Big Pharma and Big Food, not to mention the COUNTLESS advisory boards for Big Pharma and Big Food on which many of the authors serve. (But you can download the full text to see for yourself here.) Bias, anyone…?
Furthermore, without getting too deep into detail here, the interventions used in nutritional studies MATTER, yet often get ignored because many people just settle in on the conclusions found. For example, one randomized controlled trial I analyzed in my project gave group A high saturated fat and white bread, group B high monounsaturated fat with white bread and tomatoes, and group C polyunsaturated fat with white bread, tomatoes, and walnuts. You guessed it – the group receiving saturated fat and white bread had less desirable health outcomes than the other two groups. No kidding? Groups B & C were given a fighting chance with receiving fiber and antioxidants from the tomatoes and walnuts. The real thing to take from that example, is that when you are trying to compare two things, you have to actually compare two like things. A confounding factor is something that interferes with the trial in such a way that you no longer can determine cause and effect. If you didn’t give the saturated fat group tomatoes and walnuts as well, then you can’t possibly make a determination in comparison to the groups that had that extra fiber and antioxidants. HOWEVER, when the early morning news shows get ahold of the conclusion statement of these types of trials, they have no expertise or analytical skills to realize that this was crappy science; they simply report “latest study proves, yet again, that saturated fat is going to kill you.”
Ok, so when is she going to get to the point? The real conclusion I have come to through 3 months of very little sleep and 53 glorious pages of results from the analysis of 349 peer-reviewed research studies (I only included 3 of them here today) on saturated fat and heart disease published since 2010 is:
- Evidence supporting the limiting of saturated fat for the prevention or treatment of heart disease is limited at best, and evidence supporting a low-fat diet to prevent or treat high cholesterol is nonexistent.
- Saturated fat, with the exception of specific types like stearic acid, do tend to raise both LDL (bad) cholesterol and HDL (good) cholesterol. The LDL from saturated fat intake are typically “large fluffy” in nature, and therefore less likely to “clog” your arteries.
- Although high LDL is a risk factor for heart disease, high inflammation and/or oxidative stress has been found to be the catalyst causing the artery plaque to build, not LDL independently.
- A low-fat diet should not be recommended for anyone, including those looking to prevent or treat high cholesterol or heart disease.
- Future studies examining intake of saturated fat in the context of adequate omega-3 fat intake and/or fiber intake are critical to truly understanding the holistic impact of saturated fat as part of an otherwise healthy eating pattern.
- Consumers should increase intake of whole plant foods rich in fiber as well as an increased omega-3 fat intake, as well as whole-food sources of all types of dietary fat in the spirit of prevention and treatment of heart disease.
- Saturated fat can and should be a part of a holistic, moderate-fat-containing, eating style for most individuals, as the benefits of saturated fat cannot be disregarded.
- US Dietary guidelines, historically and currently, seem to be based on limited and/or flawed literature surrounding the role of saturated fat in overall health as well as the prevention and treatment of heart disease.
- Saturated fat should not be limited nor consumed in excess.
- Whole-food saturated fat sources would be best; and use of saturated fat in cooking would be ideal to prevent excessive production of free-radicals from vegetable oils.
And there you have it. What are some holistic sources of saturated fat? Well, pasture-raised and/or grass-fed meats, butter (grass-fed preferred), ghee, extra-virgin coconut oil, whole-fat dairy products (yogurt, milk, cottage cheese, cheese), nuts, seeds, etc. Including omega-3-rich fats like salmon, tuna, cod, sardines, halibut, mackerel, flaxseed, walnuts, etc., as well as TONS of whole, colorful vegetables in your daily/weekly eating routine are crucial to good health as is a little but of uncooked extra-virgin olive oil. Have less vegetable oils and less carbs (you don’t have to give them up, nor should you; but reducing carb intake is typically beneficial for most people) and try to make your carb choices 100% whole grains, whole fruits, or starchy vegetables.
Until next time…xoxox
- Keys A, Menott A, Karvonen MJ, et al. REPRINT: The Diet and 15-Year Death Rate in the Seven Countries Study. American Journal of Epidemiology. 2017;185(11):1130-1142.
- Smart NA, Marshall BJ, Daley M, et al. Low-fat diets for acquired hypercholesterolaemia. Cochrane Database Syst Rev. 2011(2):Cd007957.
- Sacks FM, Lichtenstein AH, Wu JHY, et al. Dietary Fats and Cardiovascular Disease: A Presidential Advisory From the American Heart Association. Circulation. 2017;136(3):e1-e23.