Saturated Fats

The New York Times had a headline a few years ago that read: “Butter is Back.”[1] Time magazine’s cover page stated: “Eat Butter.” As a result, people are embracing bacon, cheese, butter, and steaks as healthy. They are saying “saturated fat is good,” and “low-fat is bad.” Ironically, extensive research and scientific evidence from the last 50 years have shown that saturated-fat consumption is a predictor of LDL (low-density lipoproteins) and triglyceride levels in the body, which are also known as “bad cholesterols.” So, which message is true?

The two key reports that were published that seem to contradict decades of evidence are the 2010 and 2014 meta-analyses by Siri-Tarino et al,[2] and Chowdhury et al.[3] Both studies showed no clear association between saturated-fat intake and coronary artery disease. The media took these reports and, before you knew it, heralded the vindication of saturated fat and the promotion of beef, butter, bacon, and cheese. What should we make of these new studies?

Flawed Conclusions

We have known since 1979 that observational studies simply do not have the predictive power to correlate dietary changes with coronary artery disease risk. The meta-analysis from 2010 [2] basically clumped observational studies together, many of which would not have been able to show a correlation between diet and CAD incidence in the first place. The 2014 study published was just a rehashing of the 2010 study. Other flaws found in these saturated fats studies include:

• comparing similar populations that ate Western-type diets which were high in both fat and saturated fat;
• utilization of a single 24-hour dietary recall to determine dietary patterns; and
• adjusting for serum cholesterol.

On the other hand, controlled feeding experiments and free-living dietary change experiments have shown similar and consistent results correlating saturated-fat intake and coronary artery disease.[4][5][6][7][8][9][10][11]

Take Home #1: Do Not Jump to Conclusions When You Read a Headline

Many experts, such as Walter Willett of Harvard university and his colleagues, were concerned about the errors in the above saturated-fat studies. In fact, they even drafted a response letter to the journal raising their concerns.[12] They noticed:

• the omission of important studies
• lack of clarity on the comparison foods; and
• incorrect number citations from original studies.

You see, even top researchers did not buy into these studies that are so often cited to promote saturated fat, burgers, butter, and bacon. Responsible scientists do not jump to conclusions. We should not either.

Take Home #2: Recent Studies Do not Exonerate Saturated Fat

Since the 2014 paper came out, new reports have been published in peer-reviewed journals which go contrary to the idea that saturated fats are healthy. Some examples are below:

• In 2015, a study showed that replacing 5% of energy from saturated fat with 5% from unsaturated fats, and specifically polyunsaturated fats, lowered coronary heart disease risk by 17% and 25%, respectively.[13]
• In 2015, a study published in the Cochrane Review concluded that replacing saturated fats with starchy foods and protein did little good, but replacing saturated fat with polyunsaturated fats is more protective.[5] The report stated: Lifestyle advice to all those at risk of cardiovascular disease and to lower risk population groups should continue to include permanent reduction of dietary saturated fat and partial replacement by unsaturated fats. The ideal type of unsaturated fat is unclear..[25]
• A 2016 paper showed that saturated-fat intake increased total mortality by 8%, while polyunsaturated fatty acids and monounsaturated fatty acids lowered the risk of mortality by 19% and 11%, respectively.[14]
• In 2017, the American Heart Association released a presidential advisory paper stating that there were major weaknesses in the scientific papers supporting saturated fat, and that lowering saturated fat was still the healthy dietary recommendation.[15]
• In 2017, the Annals of Nutrition and Metabolism published a report which concluded: […] strong evidence supports the partial replacement of saturated fatty acid-rich foods with those rich in cis-polyunsaturated fatty acids to lower LDL-C and reduce the CHD risk.[16]

Take Home #3: Often, the Information Portrayed May not Even Be What the Scientists Themselves Concluded

When the 2014 paper came out, the message was “butter is back” or “bacon is back,” but interestingly, the authors of the paper themselves did not agree with this messaging. Here is a statement from the senior author of the study, Dr. Di Angelantonio: It was reported as ‘butter and burgers,’ and that’s not what our paper said […] What the paper said was that the story on saturated fat is slightly more complicated than we thought[12]

In 2016, a meta-analysis was published that seemed to suggest butter (very high in saturated fat) was not really linked with chronic diseases.[17] The media again pounced on it. Time magazine’s front cover even stated: “Eat Butter.” But again, the authors of the paper themselves did not agree with this messaging. Dariush Mozaffarian, the senior author of the paper, noted: Overall, our results suggest that butter should neither be demonized nor considered ‘back’ as a route to good health[18] Another author, Laura Pimpin, stated in the same press release: […] butter may be a ‘middle-of-theroad’ food: a more healthful choice than sugar or starch, such as the white bread or potato on which butter is commonly spread and which have been linked to higher risk of diabetes and cardiovascular disease; and a worse choice than many margarines and cooking oils—those rich in healthy fats such as soybean, canola, flaxseed, and extra virgin olive oils—which would likely lower risk compared with either butter or refined grains, starches, and sugars[18] When the authors themselves do not agree with how the media is presenting their paper, it’s a big red flag. Harvard university’s School of Public Health stated it best: Referring to butter as “healthful” is a stretch […] Journalists and broadcasters often do not get the message right. The current saturatedfat saga is a case in point.

Take Home #4: Processed and Red Meats Are not Health Foods, Despite the Ads

The International Agency for Research on Cancer (IARC), a group connected with the World Health Organization, categorizes processed meats as group 1 carcinogens (cancer-causing agent). They state: Processed meat was classified as carcinogenic to humans (Group 1), based on sufficient evidence in humans that the consumption of processed meat causes colorectal cancer[19] Other group 1 carcinogens include:

• coal gas
• Epstein–Barr virus;
• alcoholic beverages
• hepatitis B virus
• hepatitis C virus
• plutonium
• tobacco smoke
• ionizing radiation; and
• PCBs

Red meat isn’t much better, as it is categorized as a group 2A carcinogen. This means it is probably carcinogenic to humans[19] What else are in this category? Here is a sample:

• cobalt metal with tungsten carbide
• glyphosate
• lead compounds
• malaria
• petroleum refining
• nitrogen mustard
• acrylamide
• DDT; and
• human papilloma virus type 68.

Most people would be shocked to know that their hotdogs, burgers, Spam®, and Klik® are listed as cancer-causing agents. A recent study from the Adventist Healthy Study 2 cohort linked a high consumption of animal proteins with a 61% increased risk of cardiovascular mortality, whereas proteins from nuts and seeds actually decrease the risk by 40%.[20] So, don’t rush for your hotdogs and BLT sandwiches just quite yet!

ConclusionTake Home 5: Low Fat Diet Did Not Fail; The Implementation Failed

Many people say: “We tried low-fat, but it did not work!” But, did North Americans really ever go on a low-fat diet? The answer is no. As a society, we never substantially cut down on our meat and animal products, oil, and other highly processed, high-fat foods. We still ate our doughnuts, croissants, fried chicken, milk, etc. As a whole, North America never really tried a low-fat diet. Choosing lower-fat options is not the same as adopting a low-fat diet. Perhaps the healthiest low-fat diet is a whole-foods, plantbased diet. North America, in a general sense, has never tried this dietary approach.

Many people say: “We tried low-fat, but it did not work!” But, did North Americans really ever go on a low-fat diet? The answer is no. As a society, we never substantially cut down on our meat and animal products, oil, and other highly processed, high-fat foods. We still ate our doughnuts, croissants, fried chicken, milk, etc. As a whole, North America never really tried a low-fat diet. Choosing lower-fat options is not the same as adopting a low-fat diet. Perhaps the healthiest low-fat diet is a whole-foods, plantbased diet. North America, in a general sense, has never tried this dietary approach. Some people say that the issue isn’t fat, its sugar. That’s only partially true. Replacing fat with sugar is not healthy. It is not either-or; it is both-and. It is prudent to lower saturated fat and added sugar. All saturated fats, trans fat, and added sugars should be limited.

Conclusion

The bottom line is simple: To conclude that saturated fat is now on the healthy list, based on two poorly done studies, is erroneous. To suggest otherwise would be professionally irresponsible, and a blatant disregard for well-done scientific studies of the last several decades. In the meantime, what dietary advice would we suggest?

1. Focus on lowering saturated fats, not all fats. Replace saturated fats with polyunsaturated and monounsaturated fats, which can be derived from plants.
2. Avoid reductionistic thinking. Focus on whole foods, not macronutrients.
3. A whole-foods, plant-based diet has been shown to prevent, treat, and potentially reverse various chronic diseases.[21][22][23][24][25][26][27][28][29][30][31] We recommend eating whole grains, fruits, vegetables, beans, nuts, and seeds.