Let’s begin by exploring oils and fats. Oils are fats, though some fats are more solid than others. Some fats remain liquid at room temperature and are generally referred to as oils. Therefore, when discussing fats and oils, we are talking about fats as a broader category. The primary distinction between them lies in the degree of hydrogen saturation of their fatty acids. This saturation influences characteristics such as texture, stability, and behavior when heated.
There are three main categories of dietary fats: saturated, monounsaturated, and polyunsaturated. Fats with the highest degree of hydrogen saturation are referred to as saturated fats. These fats are typically solid at room temperature and melt when heated. They tend to be more shelf stable, meaning they are less prone to rancidity. Examples include lard, tallow, and tropical oils such as palm and coconut oil.
The second category consists of monounsaturated fats which include olive oil and avocado oil. Ghee and butter also contain meaningful amounts of monounsaturated fatty acids, even though they are primarily saturated fats. This mixed composition contributes to their softer texture at room temperature and semi-solid state when cooled.
The least hydrogen-saturated fats are known as polyunsaturated fats. These fats are generally more chemically fragile and thus more susceptible to oxidation and rancidity. Examples include vegetable oils such as corn oil and soybean oil.
As noted by lipid researcher Dr. Mary Enig, PhD, “none of the naturally occurring fats and oils are made up of only all saturated or all unsaturated fatty acids; rather they are mixtures of different amounts of various fatty acids” (Know Your Fats, p. 17).
General Characteristics of Dietary Fats
Fats are energy-dense and serve as carriers for fat-soluble vitamins, including vitamins A, D, E, and K. These vitamins are absorbed in the intestines and transported through the body via the bloodstream, with some being stored in the liver or fat tissue.
Historically, people around the world relied on naturally occurring fats such as butter, ghee, lard, tallow, chicken fat, olive oil, coconut oil, and palm oil as primary dietary fat sources. These fats were widely used prior to the development of industrial food processing methods in the 20th century. During that time, overall dietary patterns differed significantly from modern industrialized diets.
Some researchers, including Dr. Enig, have raised concerns about changes in dietary fat consumption associated with the increased use of industrially processed vegetable oils and hydrogenated fats. These concerns are discussed in the context of broader dietary and lifestyle shifts observed in modern populations. ¹
Polyunsaturated Vegetable Oils
Polyunsaturated fats include two well-known fatty acid families: Omega-6 and Omega-3 fatty acids. Vegetable oils are a primary dietary source of Omega-6 fatty acids, while fish and shellfish are commonly cited sources of Omega-3 fatty acids.
Vegetable oils high in the Omega-6 fatty acid linoleic acid (LA) include corn, cottonseed, soybean, and canola oils. Linoleic acid is considered an essential fatty acid, meaning it must be obtained through the diet.
Some scientific literature has explored the balance between Omega-6 and Omega-3 fatty acid intake. For example, a review published in the American Journal of Clinical Nutrition discusses dietary patterns that emphasize higher Omega-3 intake relative to Omega-6 intake in relation to cardiovascular and neurological health markers. ² These discussions reflect ongoing areas of nutritional research rather than established medical conclusions.
Stability and Processing Considerations
Polyunsaturated vegetable oils are generally less stable than saturated or monounsaturated fats, particularly when exposed to heat, light, and oxygen. Some vegetable oils are produced through industrial processing methods that may include high heat, bleaching, and chemical solvent extraction. ³ These processes can alter the oil’s chemical structure and reduce naturally occurring nutrients.
Cold-pressed oils undergo less processing and are often recommended for limited uses such as salad dressings rather than high-heat cooking. Many liquid vegetable oils are packaged in dark containers and labeled with storage recommendations due to their susceptibility to oxidation.
Oxidation can affect flavor and aroma and may contribute to the breakdown of fatty acids. For this reason, proper storage and appropriate culinary use are important considerations when selecting cooking oils.
Oxidation and Free Radicals
When polyunsaturated fats are repeatedly heated - such as in commercial deep-frying applications - their chemical structure may degrade over time. This degradation can increase the formation of oxidation byproducts, including free radicals. Free radicals are atoms or molecules with an unpaired electron.
While free radicals are naturally produced in the body, excessive amounts can contribute to oxidative stress. Dr. Richard A. Bowen, DVM, PhD, has described how oxidative processes such as lipid peroxidation can affect cellular membranes and alter their physical properties. ⁴ These mechanisms are widely studied in biological research.
Some animal studies have examined the effects of specific fatty acids, including linoleic acid, in experimental models of tumor development. ⁵ These findings contribute to scientific discussion but are not intended to establish dietary fats as causes or treatments of disease in humans.
Trans Fats
To make liquid vegetable oils more solid and shelf stable, manufacturers historically used a process known as hydrogenation. This process produces hydrogenated or partially hydrogenated oils, which contain trans fatty acids.
Trans fats were commonly used in products such as margarine, vegetable shortening, and commercially baked goods due to their stability and spreadable texture. Scientific research has associated industrial trans fats with unfavorable changes in blood lipid markers, leading to widespread reformulation efforts and regulatory changes in food manufacturing. ⁶⁻⁸
There are also naturally occurring trans fats, such as conjugated linoleic acid (CLA), which are found in meat and dairy products, particularly from pasture-raised animals. ⁹ Research institutions, including the University of Wisconsin–Madison Cook Lab, have studied CLA in experimental and observational settings. Findings from these studies describe a variety of biological effects, though ongoing research continues to clarify their relevance to human nutrition. ¹⁰
Traditional Fats
Historically, saturated and monounsaturated animal fats, along with saturated tropical oils such as coconut and palm, were commonly used in traditional diets. These fats tend to be more heat-stable and less prone to oxidation than polyunsaturated fats.
Some studies have examined how different types of dietary fats influence lipid markers such as lipoprotein(a) [Lp(a)]. ¹¹ Other research has explored how animal feeding practices, such as pasture-based versus grain-based diets, affect the nutrient composition of animal fats, including fat-soluble vitamins and CLA content.
Researchers such as Chris Masterjohn have written about vitamin K2, a nutrient found in certain animal fats, and its role in normal physiological processes related to mineral metabolism and development. ¹² These discussions reflect nutritional science research rather than medical treatment claims.
Butter is one of the oldest known dietary fats and has traditionally been produced from the milk of ruminant animals such as cows, sheep, and goats. Ghee, also known as clarified butter, is produced by removing milk solids and water from butter, resulting in a nearly pure fat. This process increases shelf stability and raises the smoke point, making ghee suitable for higher-temperature cooking. When properly prepared, ghee has a smoke point of approximately 485°F, which is higher than that of butter and many other common cooking fats.
Conclusion
Understanding the differences among fats and oils - including their composition, stability, and traditional culinary uses - can help inform dietary and cooking choices. Factors such as heat tolerance, storage stability, processing methods, and nutrient content all play a role in how fats are used in food preparation.
References
(1) "Fats and Oils and Their Impact on Health", by Mary G. Enig, PhD (http://www.westonaprice.org/Fats-and-Oils-and-Their-Impact-on-Health.html)
(2) American Journal of Clinical Nutrition, Vo. 83, No. 6, S1483-1493S, June 2006
(3) Vegetable Oil Processing- Food and Agricultural Industry (http://www.epa.gov/ttnchie1/ap42/ch09/final/c9s11-1.pdf)
(4) "Free Radicals and Reactive Oxygen" –R. A. Bowen DVM PhD/ Colorado State University (http://www.vivo.colostate.edu/hbooks/pathphys/misc_topics/radicals.html)
(5) Am J Clin Nutr 1998; 68:5–7, by Dr. Kent L. Erickson, PhD
(6) . Trans fat is double trouble for your heart health- The Mayo Clinic (http://www.mayoclinic.com/health/trans-fat/CL00032/NSECTIONGROUP=2)
(7) Trans Fatty Acids and Coronary Heart Disease - The New England Journal of Medicine, June 24, 1999 Vol. 340, No. 25
(8) Discussion by Dr. Mary Enig on Weston A. Price Foundation web site, citing research by Barnard, Dennis, University of Maryland and USDA. (http://www.westonaprice.org/Do-Saturated-Fats-and-Trans-Fats-Cause-Type-2-Diabetes.html)
(9) Influence of pasture and concentrates in the diet of grazing dairy cows on the fatty acid composition of milk. – abstract- J Dairy Res. 2003 Aug;70(3):267-76.
(10) CLA General Information- web page. (http://www.cook.wisc.edu/Generalinfo/cla.html)
(11) "...saturated fatty acids consistently decrease Lp(a) concentrations" - Arteriosclerosis, Thrombosis, and Vascular Biology. 1997; 17:1657-1661
(12) http://www.westonaprice.org/On-the-Trail-of-the-Elusive-X-Factor-A-Sixty-Two-Year-Old-Mystery-Finally-Solved.html#heart
Disclaimer:
This article provides general information about oils and fats and does not intend to endorse any products of Pure Indian Foods. It is presented for educational purposes only and is not intended to diagnose, treat, cure, or prevent any disease
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