What Fats Should We Be Eating? (Part 2)
In Part 1 of The Confusing Role of Fat in the American Diet, we provided an overview of how our changing food climate has effected the fats we consume. To summarize, industrial developments in the 1800’s and 1900’s brought about chemical processes for yielding more affordable oils. “Vegetable” oils like canola, corn, and soybean became the go-to oils for both cooking and commercialized foods. Not only did these refined oils replace the natural fats that had been prevalent in the American diet, chemical processes further refined them with a method called hydrogenation. The process of partially hydrogenating these oils creates what we know of as trans fats. Despite numerous studies warning of the health risks associated with these types of fats, they have been very popular due to their relatively low cost to produce in comparison to animal, dairy fats, and seed, nut, and fruit oils. The greatest problem with the consumption of vegetable oils is their pro-inflammatory effect they have on the body and the lack of nutrients they provide.
Warnings against the consumption of saturated fatty acids (SFA) – the primary fat in animal fat, dairy, and coconut oil – has been debated heavily since the increasing popularity of vegetable oils. Claims that saturated fat leads to high cholesterol, heart disease, and stroke are made by public organizations like the American Heart Association (1) despite new research that speaks to the contrary. Old studies found that upon consumption of SFA, a slight increase in LDL cholesterol (commonly thought of as the “bad cholesterol”) was noted. These studies subsequently left off their findings that a corresponding, and often greater, increase in HDL cholesterol was also observed (2). HDL cholesterol is thought of as the “good cholesterol” because it has the effect of lowering risk of cardiovascular disease.
A Brief History of Fats in America
Many researchers have taken to examining old studies with negative findings in regards to saturated fatty acids, and have seen that the recommendations made previously do not have much weight (3, 4). One important factor is that previous studies did not take into account whether the animal fat consumed was from conventionally raised or free-range livestock. Conventionally raised animals have a very different body composition than those that are allowed to graze outdoors in an open field. Free-range animals will always have an optimal fat profile in comparison to conventionally raised animals (5). Additional studies are finding that increased saturated fatty acids intake actually decreases risk of cardiovascular disease (6, 7).
In fact, there is mounting evidence proving that carbohydrates are the driving factor behind fat metabolism due to the effect on insulin (8), as we discussed in our recent article Why We Are Sugar Addicts.
This evidence in regards to carbohydrates makes recommendations like Choose My Plate by the United States Department of Agriculture (USDA) very problematic. Their graphic depiction of an idea plate shows nearly 50% of the plate covered with fruits and grains, both forms of carbohydrates (9). There is no category for fat shown anywhere in the graphic, leading to an assumption that only trace amounts of fat are to be obtained through protein and dairy, which are shown depicted in the graphic. From what we now know about the effects of a low fat, high carbohydrate diet, these recommendations can only lead to further incidence of obesity, heart disease, and other degenerative diseases.
What Fats Should We Eat?
Not only should we be including saturated fats from healthy sources (free-range animal meats, organic coconut oil), studies have also shown the benefits of including moderate amounts of unsaturated fats in our diet. Oils from sources like olives, avocados, and sesame seeds contain high amounts of monounsaturated fats (MUFA) and vitamin E, which is a potent anti-inflammatory that is lacking in the American diet. MUFAs are proven to encourage healthy blood pressure levels, improve insulin sensitivity, and reduce incidence of cardiovascular disease (10). These anti-inflammatory benefits are in direct contrast with the pro-inflammatory effect of vegetable oils, which are high in omega-6 type polyunsaturated fats. High levels of omega 6 fatty acids in comparison to omega 3 result in pro-inflammatory conditions in the heart (11), brain (12), and overall body composition (13).
Most Americans are still influenced from years of being told that fat is bad. They may cut back on the trans fatty acids but continue to consume refined vegetable oils, resulting in a diet high in omega-6 fatty acid. You can improve your health by throwing out the margarine, Crisco, and vegetable oils and instead consuming a moderate amount of heart healthy fats. Shoot for a balance of saturated fat (free-range animal products and butter, organic coconut or palm oils), monounsaturated fat (olives, avocado, and sesame seeds, and omega-3 type polyunsaturated fats (wild fish and chia seeds).
Saturated Fats, American Heart Association, 2014: http://www.heart.org/HEARTORG/GettingHealthy/FatsAndOils/Fats101/Saturated-Fats_UCM_301110_Article.jsp
Saturated Fat and Cardiovascular Disease: The Discrepancy…, Nutrition Journal, 2011: http://www.nutritionjrnl.com/article/S0899-9007(11)00314-5/fulltext
Saturated Fat and Cardiometabolic Risk Factors…, Springer Link, 2010: http://link.springer.com/article/10.1007/s11745-010-3393-4/fulltext.html
Saturated Fat, Carbohydrate, and Cardiovascular Disease, The American Journal of Clinical Nutrition, 2010: http://ajcn.nutrition.org/content/91/3/502.full
Dietary Intake of Saturated Fat by Food Source…, American Journal of Clinical Nutrition, 2012: http://ajcn.nutrition.org/content/96/2/397.full
Should Animal Fast Be Back on the Table?…, Animal Production Science, 2014: http://www.publish.csiro.au/view/journals/dsp_journal_fulltext.cfm?nid=72&f=AN13536
Dietary Fatty Acids and Oxidative Stress in the Heart Mitochondria, 2010: http://www.sciencedirect.com/science/article/pii/S1567724910001431
Fatty Acids, Obesity, and Insulin Resistance: Time for a Reevaluation, American Diabetes Association, 2011: http://diabetes.diabetesjournals.org/content/60/10/2441.full
Choose My Plate Diagram, USDA, 2014: http://www.choosemyplate.gov/images/MyPlateImages/JPG/myplate_green.jpg
Dietary Monounsaturated Fatty Acids are Protective Against Metabolic Syndrome and Cardiovascular Disease Risk Factors, Springer Link, 2011: http://link.springer.com/article/10.1007/s11745-010-3524-y
The Balanced Omega-6/Omega-3 Fatty Acid Ratio, Cholesterol, and Coronary Heart Disease…, Australian Journal of Medical Science, 2011: http://search.informit.com.au/documentSummary;dn=637391976224392;res=IELHEA
Evolutionary Aspects of Diet: The Omega-6/Omega-3 Ratio and the Brain, Springer Link, 2011: http://link.springer.com/article/10.1007/s12035-010-8162-0
Importance of a Balanced Omega 6/Omega 3 Ratio for the Maintenance of Health, La Paz Hospital of Madrid, 2011: http://scielo.isciii.es/pdf/nh/v26n2/13_original_06.pdf