Artificial trans fats are bad for you for three reasons. First, they raise bad cholesterol without raising good cholesterol, and they damage the lining of blood vessels. Second, they are linked to insulin resistance and type 2 diabetes. Third, they drive chronic inflammation. The richest source is processed food made with partially hydrogenated vegetable oil.
A couple of years back, fast food Sunday treats were the norm for most families. Then people slowly got more health-conscious. Families began to switch to healthier places to eat, with less processed food on the menu. Some gen Ys saw fast food banned from the family menu. For them, here are the 3 reasons we made the switch. This may also help people who have probably heard that “processed fats are not good for you” but never heard why. Next time you pick some fried or baked food from a random store, take the time to check. Find out if unhealthy trans fats are on the ingredient list.
What are Trans Fats?
Trans fats are a form of unsaturated fat. They can come from both natural and artificial sources. Natural trans fats are found in meat from ruminant animals (animals with a multi-chamber stomach), such as cattle, sheep, and goats. These trans fats form naturally during digestion in the ruminant’s stomach. So they show up in dairy products and in cuts of beef and lamb. The trans fats that occur naturally are not much to worry about. Science has shown they have a decent safety profile when people eat them in moderate amounts. The common natural trans fat is conjugated linoleic acid (CLA). It is found mostly in dairy. It has been found to have some therapeutic benefits, including help with weight loss and bodybuilding. Because of this, CLA is usually sold as a dietary supplement.
Artificial trans fats, on the other hand, may cause more harm than good. People often call them industrial fats or partially hydrogenated fats. They are made from vegetable sources. Then they are artificially changed so they stay solid at room temperature and last longer. You can find them in fried foods such as doughnuts. You also find them in baked goods such as cakes, pie crusts, biscuits, frozen pizza, and cookies. Science has shown that artificial trans fats carry serious health risks. Those risks should steer you away from them.
Are trans fats bad for your heart?
Artificial trans fats may increase your risk of heart disease, as some clinical studies have shown. Vanaspati ghee and margarine have high levels of artificial trans fats. It has been shown that people who eat a lot of artificial trans fats are likely to have more bad cholesterol. Their good cholesterol does not rise to match. Other fats, on the other hand, raise both bad and good cholesterol. According to CDC reports 2019, high levels of low-density lipoprotein (bad cholesterol) may raise one’s risk for heart disease and stroke. A number of significant studies have shown that eating artificial trans fats is linked with cardiovascular disease (heart and blood vessel disease).
Trans fats have also been shown to damage the inner lining of blood vessels. This lining is called the endothelium. A diet rich in hydrogenated fats can lead to impairment in blood vessel function.
Do trans fats cause insulin resistance and type 2 diabetes?
The link between trans fats and insulin sensitivity is still murky. More clinical research is needed to give clear direction. One study was done by the University of Minnesota in 2006. It concluded that “high intakes of trans fats may increase the risk for type 2 diabetes, inconsistencies across studies and methodological problems make it premature to draw definitive conclusions at this time. More experimental research in humans is needed to further address this question.”
However, one large study showed that people who ate the most trans fats had a 40% higher risk of diabetes. A number of animal studies have also shown a positive correlation. More artificial trans fats went with more insulin resistance (when cells stop answering insulin). Insulin resistance makes type 2 diabetes more likely.
Do trans fats cause inflammation?
Inflammation is a needed and useful response when injury or infection has occurred. But chronic inflammation has been linked to the root cause of many long-term diseases. These include heart disease, metabolic syndrome, diabetes, and arthritis. A study came out in 2002. It showed a positive correlation between a diet high in hydrogenated fat and inflammatory cytokines (chemical signals of inflammation). Those cytokines have been associated with atherosclerosis (hardening of the arteries). Other studies have also shown that trans fats raise inflammation. This is most true in people who are overweight or obese.
In 2015, the Food and Drug Administration (FDA) banned the use of trans fats in food preparation. They “determined that PHOs, the major source of artificial trans fat in the food supply, are no longer “Generally Recognized as Safe,” or GRAS.” But the ban has not been put in place to date. That is why so many processed foods still contain unhealthy trans fats. Processed foods made with partially hydrogenated vegetable oil are the richest source of trans fats in the modern diet.
How can I avoid trans fats?
- Eat a healthy diet with more fruits, vegetables, full-fat dairy products, red meat, poultry, fish and nuts. These foods are less likely to contain unhealthy trans fats. Skip refined grains. Gluten and gliadin in grains drive leaky gut and autoimmune problems.
- Cut back on processed foods made with partially hydrogenated oil. Examples are doughnuts, cookies, crackers, muffins, pies, and cakes.
- Cook your food more often with real olive oil. Skip seed oils such as canola and sunflower oil, even when they are not hydrogenated. Seed oils are harmful too.
- When you buy food, read the label. Check for anything partially hydrogenated on the ingredient list.
Natural trans fats from animal products are considered safe in moderate amounts. But eating artificial trans fats on a regular basis could put your health at risk.
Eating a lot of artificial trans fats has been linked to long-term inflammation, insulin resistance, and cardiovascular disease. Sadly, most Americans are hooked on fast food. Fast food is the biggest culprit for unhealthy trans fats.
Frequently asked questions
What foods are high in trans fat?
The richest source is processed food made with partially hydrogenated vegetable oil. That means fried foods such as doughnuts. It also means baked goods such as cakes, pie crusts, biscuits, crackers, muffins, cookies and frozen pizza. Margarine and vanaspati ghee carry high levels too. Fast food is the biggest culprit in the American diet. Check the ingredient list for anything partially hydrogenated before you buy.
Are the natural trans fats in meat and dairy bad for you?
No. Natural trans fats form during digestion in the stomachs of cattle, sheep and goats. So they show up in beef, lamb and dairy. Eaten in moderate amounts they have a decent safety profile. The most common one is conjugated linoleic acid (CLA). It is found mostly in dairy and is even sold as a supplement. The harm comes from artificial trans fats made from vegetable oils.
Are trans fats banned in the United States?
In 2015 the Food and Drug Administration made a ruling. It said partially hydrogenated oils, the main source of artificial trans fat, are no longer generally recognized as safe. The ban has been slow to reach the shelf. So many processed foods still contain them. Do not assume a packaged food is free of trans fats. Read the label and look for partially hydrogenated oil in the ingredients.
Is margarine a trans fat?
Margarine made with partially hydrogenated oil is one of the most concentrated sources of artificial trans fat. So is vanaspati ghee. Hydrogenation keeps a vegetable oil solid at room temperature, so it lasts longer on the shelf. That same process creates the trans fats. Those trans fats raise bad cholesterol without raising good cholesterol, and they damage the lining of your blood vessels.
References
- FDA (2018): Trans Fat. Retrieved from https://www.fda.gov/food/food-additives-petitions/trans-fat
- NCBI (2014): Trans fatty acids – A risk factor for cardiovascular disease. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3955571/
- CDC: Cholesterol myths and facts. Retrieved from https://www.cdc.gov/features/cholesterol-myths-facts/index.html
- NCBI (2007): A prospective study of trans fatty acids in erythrocytes and risk of coronary heart disease. Retrieved from https://www.ncbi.nlm.nih.gov/pubmed/17389261
- NCBI (2006): Trans fatty acids, insulin resistance, and type 2 diabetes. Retrieved from https://www.ncbi.nlm.nih.gov/pubmed/16958313
- NCBI (2002): Effect of hydrogenated and saturated, relative to polyunsaturated, fat on immune and inflammatory responses of adults with moderate hypercholesterolemia. Retrieved from https://www.ncbi.nlm.nih.gov/pubmed/11893781
Related reading
- Conjugated Linoleic Acid: Is It Good for You?
- Chronic Inflammation and Cancer Risk
- GGT blood test: the oracle of death
- Foods behind chronic inflammation
Medically reviewed by Dr. Gurpreet Singh Padda, MD, MBA, MHP
Interventional pain physician, addiction medicine specialist and obesity medicine diplomate.
Licensed in Missouri and Illinois.
Last reviewed June 18, 2026
