What is trans fat?
Trans fats (or trans fatty acids) are unsaturated fats that food scientists can identify by their unique molecular structure.1 They can occur naturally in foods, but they can also be artificially created by food manufacturers.
Natural Trans Fat
Naturally-occurring trans fats can be found in small amounts in the meat and dairy products of grazing animals like cows, sheep, and goats. Trans fats account for roughly 3-6% of the fat in dairy and 3-9% of the fat in meat from these animals.2
Artificial Trans Fats
Food manufacturers can create artificial trans fats by adding hydrogen to liquid vegetable oils to reduce production costs, extend shelf life, and improve food texture. This oil is often listed in ingredients as partially hydrogenated oil.
How do trans fats affect my body?
Artificial trans fatty acids are so dangerous to your cardiovascular health that governments around the globe are banning them from the food supply.3
Researchers have demonstrated that trans fats can:
- Raise LDL ("bad") cholesterol levels
- Lower HDL ("good") cholesterol levels
- Increase inflammation throughout the body
- Damage vascular cells
- Increase the risk of heart disease, stroke, and type 2 diabetes
Naturally-occurring trans fats are generally not considered harmful in moderation.4
How much trans fat should I consume?
Try to eliminate all artificial trans fats from your diet. Even small amounts can be harmful. According to Harvard Medical School, "For every 2% of calories from trans fat consumed daily, the risk of heart disease rises by 23%." 5
Which foods are high in trans fat?
The U.S. Food and Drug Administration (FDA) announced in June of 2015 that all restaurants and grocery stores would be required to eliminate partially hydrogenated oils (the main source of trans fats) from their products within three years. While the ban officially took effect on June 18, 2018, the FDA provided a one-year extension to several manufacturers. The FDA also extended the deadline for removing these products from grocery store shelves to January 1, 2021.6 For these reasons, you should continue checking food labels for trans fats and partially hydrogenated oils. Pay particular attention to the following food categories:
- Fried foods
- Frozen foods (especially pies and pizzas)
- Baked goods
- Stick margarine
- American Heart Association: Trans Fats
- Mayo Clinic: Trans fat is double trouble for your heart health
- Leech, J., MS. (2017, July 4). Why Are Trans Fats Bad for You? The Disturbing Truth. Healthline.
- Aro, A., Antoine, J., Pizzoferrato, L., Reykdal, O., & Poppel, G. V. (1998). Trans Fatty Acids in Dairy and Meat Products from 14 European Countries: The TRANSFAIR Study. Journal of Food Composition and Analysis, 11(2), 150-160.
- WHO plan to eliminate industrially-produced trans-fatty acids from global food supply. World Health Organization.
- Gebauer, S. K., Chardigny, J., Jakobsen, M. U., Lamarche, B., Lock, A. L., Proctor, S. D., & Baer, D. J. (2011). Effects of Ruminant trans Fatty Acids on Cardiovascular Disease and Cancer: A Comprehensive Review of Epidemiological, Clinical, and Mechanistic Studies. Advances in Nutrition, 2(4), 332-354.
- Types of Fat. Harvard School of Public Health.
- Final Determination Regarding Partially Hydrogenated Oils (Removing Trans Fat). U.S. Food and Drug Administration.