And honestly?
This one earned its reputation.
Nutrition can get frustrating because recommendations change, studies contradict one another, and foods we were once told were terrible sometimes turn out to be much more complicated than that.
Trans fat is different.
We have strong evidence that trans fat increases cardiovascular risk, and industrially produced trans fats have no known health benefit. The World Health Organization recommends keeping total trans-fat intake below 1% of daily energy intake and avoiding industrially produced trans fats (World Health Organization [WHO], 2024).
But here’s what’s interesting:
If trans fats are so bad, are we even still eating them?
The answer is very different today than it was twenty years ago.
What Is Trans Fat?
Trans fat is a type of unsaturated fat with a particular chemical structure.
Small amounts occur naturally in foods from ruminant animals such as cows, sheep, and goats. That means beef and dairy can naturally contain some trans fat.
The bigger public-health concern has been industrially produced trans fat.
For decades, manufacturers used partial hydrogenation to make liquid vegetable oils more solid and stable. Partially hydrogenated oils helped improve texture, withstand processing, and extend shelf life.
Great for manufacturing.
Not so great for our bodies.
Why Are Trans Fats Bad for You?
Trans fat raises LDL cholesterol, often called “bad” cholesterol. Higher LDL contributes to cardiovascular disease (U.S. Food and Drug Administration [FDA], n.d.).
Higher trans-fat intake is also associated with greater risk of coronary heart disease and death. WHO recommends keeping total trans fat below 1% of daily energy intake, which is less than about 2.2 grams per day for someone eating 2,000 calories (WHO, 2024).
But there’s an important distinction here:
Trans fat being harmful does not mean fat is harmful.
Fat Isn’t the Problem
We need dietary fat.
Fat is part of our cell membranes. It provides energy and helps us absorb vitamins A, D, E, and K. Certain fats also provide essential fatty acids our bodies can’t make on their own.
The type and source of fat matter.
Foods like fatty fish, avocados, olives and olive oil, nuts, seeds, eggs, and other whole or minimally processed foods can absolutely be part of a nutritious diet.
Omega-3 fats, for example, are essential and play important roles in cell membranes, brain function, and inflammatory signaling.
Nuts and seeds provide unsaturated fats along with fiber, protein, minerals, and plant compounds.
Avocados provide mostly unsaturated fat along with fiber and potassium.
Olive oil is rich in monounsaturated fat.
And healthy food is allowed to taste good.
A salad isn’t automatically healthier because you refused to put dressing on it.
Use the olive oil.
Add the avocado.
Put some nuts on it.
Healthy eating isn’t supposed to be punishment.
So when I say we’re better off without industrial trans fats, I’m not saying we should fear fat.
I’m saying we should understand the difference between fats.
So Where Did All the Trans Fat Go?
This is the part of the story I actually love.
We learned something was harmful, and the food supply changed.
Partially hydrogenated oils were once the major source of artificial trans fat in American processed foods.
In 2015, the FDA determined that partially hydrogenated oils were no longer “Generally Recognized as Safe.” Most manufacturers had to stop adding them to foods beginning in 2018, with later compliance dates for some products. The FDA later completed additional regulatory cleanup involving partially hydrogenated oils.
That’s a public-health success worth acknowledging.
It also means some older nutrition advice about trans fat is outdated.
If you read an old article saying every tub of margarine, coffee creamer, frozen pizza, donut, or order of french fries is packed with partially hydrogenated oil, don’t automatically assume that’s still true.
Food formulations have changed.
Globally, however, industrial trans fat hasn’t disappeared everywhere. WHO continues working toward eliminating it from food supplies around the world (WHO, 2024).
Can “0 Grams Trans Fat” Still Mean Some Trans Fat?
Yes.
Under FDA labeling rules, if a serving contains less than 0.5 gram of trans fat, the Nutrition Facts label can list it as 0 g (FDA, 2003).
Historically, that meant a product could contain a small amount of partially hydrogenated oil while still saying “0 grams trans fat.”
That’s much less relevant now that partially hydrogenated oils have largely been removed from the U.S. food supply.
But the larger lesson still applies:
The front of a package doesn’t tell you everything about the food.
Turn it around.
Read the ingredients.
Look at the nutrition label.
What About Naturally Occurring Trans Fat?
Small amounts of trans fat occur naturally in meat and dairy from ruminant animals. WHO recommends keeping total trans-fat intake low regardless of source (WHO, 2024).
That doesn’t mean I’m going to panic because yogurt or steak contains a small amount.
Food is more than one molecule.
A food can contain protein, vitamins, minerals, different fatty acids, and other nutrients at the same time.
That’s why I prefer looking at the overall pattern of someone’s diet instead of teaching people to fear individual foods.
“Zero Trans Fat” Doesn’t Automatically Mean Healthy
Removing industrial trans fat was a good thing.
But:
A cookie doesn’t become broccoli because the trans fat disappeared.
A package can scream:
0 G TRANS FAT!
and still contain plenty of added sugar, sodium, refined grains, or other ingredients you probably don’t want making up most of your diet.
That doesn’t mean you can never eat the cookie.
I don’t eat perfectly, and I don’t think health requires us to.
It just means one claim on the front of a package shouldn’t make the decision for you.
My Take on Trans Fat
I prefer looking at food as a whole.
What is it made from?
What nutrients does it provide?
What types of fat does it contain?
How does it fit with everything else I’m eating?
And yes, do I actually enjoy it?
Industrial trans fat is one thing I’m perfectly comfortable saying we’re better off having largely removed from the food supply.
But that doesn’t mean fat is the enemy.
Eat the avocado.
Use the olive oil.
Enjoy the nuts.
Eat the salmon.
Have the occasional donut if you want the donut.
Just don’t let a giant “0 GRAMS TRANS FAT” banner convince you the donut suddenly became a health food.
Nutrition is bigger than one nutrient.
And thankfully, when it comes to industrial trans fat, we’ve already made a lot of progress.
Frequently Asked Questions
Are trans fats banned in the United States?
Not exactly. Partially hydrogenated oils, once the major source of artificial trans fat in processed foods, have been removed from most uses in the U.S. food supply. Small amounts of naturally occurring trans fat still exist in foods such as meat and dairy (FDA, n.d.; WHO, 2024).
Can something labeled “0 g trans fat” contain trans fat?
Yes. FDA labeling rules allow less than 0.5 gram of trans fat per serving to be listed as 0 grams (FDA, 2003).
What foods still contain trans fat?
Small amounts occur naturally in meat and dairy from ruminant animals. Industrial trans fats have largely disappeared from the U.S. food supply but may still occur in other parts of the world depending on local regulations (WHO, 2024).
References
U.S. Food and Drug Administration. (2003). Small entity compliance guide: Trans fatty acids in nutrition labeling, nutrient content claims, and health claims. U.S. Department of Health and Human Services.
U.S. Food and Drug Administration. (n.d.). Trans fat. U.S. Department of Health and Human Services. https://www.fda.gov/food/food-additives-petitions/trans-fat
World Health Organization. (2024). Trans fat. https://www.who.int/news-room/fact-sheets/detail/trans-fat
