Alongside sugar, trans fat has been one of the most demonized ingredients out there.

And rightfully so.

Trans fats are made from vegetable oils. The process of hydrogenation turns them from liquid to semi-solid form to improve shelf life and prevent them from spoiling.

However, this type of trans fat is shown to be extremely unhealthy. Causing everything from heart disease to chronic inflammation.

In fact, the FDA banned trans fats on June 18, 2018. Products that were produced before that can still be sold until their expiry date, which is around 2020 or 2021. (2)

In this article, we’ll answer your questions; including what is trans fat, how it’s made, and why it’s so dangerous.

How is Trans Fat Made?

Natural Trans Fat

Trans fat is a type of unsaturated fat.

As it turns out, not all trans fat is the same.

You have natural trans fat and man-made trans fat.

Some animals naturally produce trans fat in their stomachs with the help of bacteria. This type of fat makes up only a small percent of total fat in certain dairy and animal products.

Artificial Trans Fat

By contrast, manmade trans fat is created from vegetable oils.

Hydrogen molecules are added to the oil which turns it from liquid to semi-solid form. This process is called hydrogenation.

Hydrogenated oils have longer shelf-life, are cheap to make, and add a pleasurable taste to your food.

Which One is Worse?

The evidence on man-made trans fats vs natural trans fats is still limited.

But so far, most research points to the fact that natural trans fats are less harmful.

In fact, evidence suggests that foods with trans vaccenic acid (VA), which is naturally found in dairy and beef, can actually lower your risk of obesity, diabetes, and heart disease. (1)

Why is Manmade Trans Fat Bad?

Okay, so now that we established the difference between natural and artificial trans fats, let’s examine why exactly manmade trans fat is bad for you.

The problem is that artificial trans fats have no benefits for your body.

Not only that, they cause a wide range of health problems, including:


A reputable study showed that trans fats increase your risk of developing allergies. This includes conditions like asthma, eczema, and allergic cold. Some countries have even restricted the use of trans fats, or even banned them. These include the USA, Denmark, Britain, and Switzerland. (3)

Cardiovascular Disease

One of the worst side effects of trans fats is heart disease.

Once they enter your body, trans fats increase your “LDL” or bad cholesterol. At the same time they reduce the “HDL” or good cholesterol. (6)

Trans fats also (6) :

  • Increase your triglyceride levels
  • Make your blood vessels more “stiff” by inhibiting vascular relaxation
  • Cause blood clots to form at a higher than normal rate
  • Induce systemic inflammation

All of these factors are huge contributors to heart disease and stroke.

So it’s no surprise to know that numerous studies have confirmed that trans fats can increase your risk of heart attack and other cardiovascular problems. (4, 5)


Trans fats also link to diabetes and blood sugar problems. That’s because trans fat can make you resistant to insulin, a hormone which helps you absorb sugar into cells. When you have insulin resistance, your blood sugar stays high which can potentially lead to type 2 diabetes. (6)

Pregnancy Complications

The risk of pregnancy complications increases when the mother consumes trans fats.

That’s because trans fats can cross the placenta, which could increase the risk of fetal impairments. (6)

Inflammation & Cancer

As we saw, trans fats aren’t well accepted by your body. Whenever you ingest them, this triggers a systemic inflammation in the body. Chronic, low-grade inflammation has been linked to a number of diseases, including cancer. (11, 12)

A study led by Lenore Kohlmeier showed alarming results about trans fats and cancer. The study found a link between having higher body stores of trans fat and an increased risk of breast cancer in women. (7) However, it’s important to note that we need more research to see whether the same applies to other populations.

Foods With Hidden Trans Fats

There are two ways you can check if food has trans fats:

  1. By looking directly at the nutrition facts label
  2. By searching through the ingredient list for “partially hydrogenated oils”. These are simply trans fats masked under another name.

Note: Foods that have less than 0.5g of trans fats per serving can still be labeled as having 0g of trans fats. (10) So checking the nutrient facts label is not the best way to ensure that there are absolutely no trans fats in your product. The only way to know for sure is by checking the ingredient label; if it says “partially hydrogenated oils” anywhere, it means there is trans fat there.

With that said, here are some of the most common foods with trans fats:

Certain Types of Popcorn

There are two most common varieties of popcorn: air-popped popcorn and microwave popcorn.

Air-popped popcorn is a healthy snack. It’s not only full of fiber but is also low in fat and calories.

Microwave popcorn, on the other hand, may contain trans fats. Not all of them do, but some still include it. Certain food producers typically use partially hydrogenated oils in popcorn. It has a high melting point, which means the oil stays solid until you put popcorn in the microwave to melt. This gives it a nice flavor as you can imagine, but it’s not worth the health risk.

Some Vegetable Oils & Margarines

Some types of vegetable oil can still contain trans fat.

Not long ago, many food companies made margarine from trans fats. Since hydrogenation solidifies oil, it made for a perfect ingredient to make margarine.

Luckily, this practice is out of fashion nowadays. Most food companies now use trans-fat-free margarine. However, it’s still important to check the food label to make sure there’s no partially hydrogenated fat in there.

What’s more, some non-hydrogenated oils can also contain trans fat. I know, it sounds counterintuitive; how can a non-hydrogenated oil contain trans fat?

Well, as it turns out, testing has shown that vegetable oils such as canola, corn, and soybean oil, can have up to 4.2% of total fat coming from trans fat. (8, 9)

So if you’re looking to minimize your consumption of trans fat, your best bet would be to replace margarine and vegetable oils with healthier alternatives. These include coconut and olive oil.

Dairy-Free Coffee Creamers

As the name suggests, dairy-free coffee creamers don’t contain any milk or cream for coffee.

Instead, their main ingredients are sugar and oil.

In the past, most food companies used trans fats in dairy-free coffee creamers to prolong their shelf life and add a creamier texture. But in recent years, they’ve minimized trans fat use.

Still, it’s important to check for the ingredients on the label. This way you’ll be at peace knowing you aren’t drinking something that could potentially harm you.

Some Potato Chips

Most brands of potato chips don’t have trans fat nowadays. But like with other food on this list, it’s important to double-check the label to ensure that’s really the case. It’s still possible for some potato chips to contain partially hydrogenated oils.


Certain brands of pizza still contain trans fats. It’s mostly found in the dough part of the pizza. Keep your eye on these things; especially frozen pizzas as those are known to contain partially hydrogenated oil.

Baked Goods

Baked goods such as muffins, pastries, donuts, and cakes are sometimes made from vegetable shortening and margarine, both of which are known to have trans fat in them.

Vegetable shortening is interesting because it makes the pastry soft and flaky, giving it that distinct taste and texture. It also prolongs its shelf life. That’s one of the reasons why you can leave some baked goods out in the air for so long without spoiling.

However, these days, as trans fat is slowly being phased out from margarine and vegetable shortening, fewer and fewer bakery products contain trans fats.

Still, this doesn’t guarantee there won’t be trans fats in that donut you buy. It’s important to read the label where possible and avoid eating pastries with hydrogenated vegetable oil.

Better yet, why not make your own baked goods at home. This way you’ll have the complete control of the ingredients.

Sweet Pies & Meat Pies

Some pies contain hydrogenated oil in the crust. Trans fat gives the crust soft and flaky texture and pleasurable taste. Ideally, you’ll want to make your own pies to have a peace of mind knowing what you’re eating. Or if that’s not possible, try to find out the nutrition facts about the pie.

Canned Frosting

Canned frosting mostly consists of water, sugar, and oil. Some brands still do contain partially hydrogenated oils, so it’s important to watch out for the ingredients – even if on the label it says there’s 0g of trans fat!

French Fries & Burgers

Burgers and french fries may be last on our list but they are among the most likely foods to have trans fats. They’re often fried with vegetable oils, and oftentimes, these vegetable oils are re-used multiple times which increases their trans fat content and harmful effects.

You’ll find it hard to avoid trans fats when eating fast foods. For this reason, your best bet is to minimize their consumption. Or better still, not eat them at all.

How to Avoid Trans Fat?

Avoiding trans fat is all about navigating food labels correctly. I’ve linked an article we wrote on navigating food labels if you want to know more.

Here’s what the American Heart Association recommends (13):

  1. When buying processed food, look for those that contain unhydrogenated oil instead of hydrogenated or partially hydrogenated vegetable oils or saturated fats.
  2. Emphasize fruits, vegetables, whole grains, fish, nuts, poultry, and low-fat dairy products in your diet.
  3. Replace vegetable oils which may contain trans fat with healthy alternatives, such as olive oil.
  4. Crackers, donuts, pies, cakes, muffins, and cookies are foods that may contain hydrogenated vegetable oils, aka, trans fats. Limit how often you eat them.
  5. Limit your intake of commercially available baked good and fried foods that contain shortening or hydrogenated vegetable oils. Not only are they high in fat, but that fat is also trans fat.

Conclusion – Final Thoughts

Not long ago, you could find trans fat everywhere. Just like sugar nowadays.

Luckily, it’s been less and less used, and the U.S. federal agency FDA has banned its use in 2018.

However, even despite these things, there are still foods out there that contain trans fats. That’s why it’s important that you read the label to know what you’re buying.

American Heart Association recommends avoiding baked goods and fried foods as these tend to be high in trans fat. Some of these foods are fried in vegetable oils. Every time oil is reused for frying, its trans fat content multiples and it becomes even more harmful.

There are foods which are okay to eat in moderation, even though they not might be healthy per se. But trans fat is one of those things you should cut out for good. With countless evidence proving its negative effects on your heart, blood sugar, and overall health, there’s absolutely no benefit in having it on the plate.

Top Questions About Trans Fat

Are all trans fats bad for you?

Not all trans fats are made equal. In fact, there’s natural trans fat which is produced by bacteria in animal’s stomach. This means that certain animal products like dairy and meat (particularly red meat) contain trace amounts of natural trans fats. Research shows that these types of fats don’t harm our health; they may in fact improve it. (1)

Can trans fats be burned off?

Yes, trans fats can be burned off just like all other fats in your body. Basically, once you eat food, your body breaks it down into fatty acids (such as saturated, polyunsaturated, and trans fats), some of which then go to the liver and bloodstream, while others are stored as fat. The more trans fat you eat, the more of it you’ll have stored in your body. When your body uses it for energy, trans fat is broken down just like other fats. However, the problem with them is that they raise your bad cholesterol while reducing good cholesterol. Trans fats also cause inflammation and blood plaquing, which is no bueno.

How much trans fat is okay?

American Heart Association recommends getting no more than 1% of your total calories from trans fats. This includes both natural and man-made trans fats. (13, 14)

Does trans fat make you fat?

Trans fat is just like any other type of fat in terms of its caloric value. Fat has 9 calories per gram. Obviously, fat as a macronutrient is more calorie-dense than carbohydrates and proteins, which have 4kcal per gram. If you eat too much of it, it’s possible to gain excess body fat. Ultimately, it all boils down to how many calories you spend vs. how many you consume, regardless if it’s fat, carbs, or protein that you’re getting your calories from.


  1. Natural Trans Fats Have Health Benefits, New Study Shows. (source)
  2. Final Determination Regarding Partially Hydrogenated Oils (Removing Trans Fat). (source)
  3. Phase II of the International Study of Asthma and Allergies in Childhood (ISAAC II): rationale and methods. (source)
  4. Dietary fat intake and risk of coronary heart disease in women: 20 years of follow-up of the nurses' health study. (source)
  5. Association between trans fatty acid intake and 10-year risk of coronary heart disease in the Zutphen Elderly Study: a prospective population-based study. (source)
  6. What is Trans Fat? (source)
  7. Adipose Tissue Trans Fatty Acids and Breast Cancer in the European Community Multicenter Study on Antioxidants, Myocardial Infarction, and Breast Cancer. (source)
  9. Rapid FT‐NIR Analysis of Edible Oils for Total SFA, MUFA, PUFA, and Trans FA with Comparison to GC. (source)
  10. Small Entity Compliance Guide: Trans Fatty Acids in Nutrition Labeling, Nutrient Content Claims, and Health Claims. (source)
  11. Chronic Inflammation. (source)
  12. Chronic inflammation in cancer development. (source)
  13. Trans fat. (source)
  14. Facts about trans fats. (source)

Write a comment