Food Fight

Why trans fat is bad
September 10, 2006, 2:42 am
Filed under: chemistry, fat, nutrition

We all hear about trans fat being bad, but you rarely hear about what it is or why it is bad. I thought about writing it up here, but, frankly, that seemed like a lot of work, and besides, I am not the expert by any stretch. Fortunately, Molecule of the Day, my favorite chemistry blog, read my mind and did a post about trans fats (trans fatty acids, to be precise) the same day that I emailed him my request. Go MOTD! Another good expanation about trans fat. is Wikipedia, especially the discussion page.

It might be a bit much if you don’t have much of a chemistry background, so I’ll try to add my own little explanation: some fat is straight and hard, and some is bent and soft (and we call it oil). Hard fat is bad. This is saturated fat. But we like it because it is good for processed food (including the processing we do at home like baking cookies).

Saturated fat (like butter) is more expensive than oil. So they take the oil, the bent fat, and straighten it out to make it hard. The bends are caused by some double bonds of carbons. Bonds can be bent (called cis) or straight (trans). In nature, they almost always are cis. But with some processing, we can either add some hydrogen to make them saturated fats, or convert the cis double bonds to trans bonds. Both of these changes straighten out the oil, making is harder fat.

This is partially hydrogenated oil, or trans fat. It is shaped like saturated fat, and so it behaves more like saturated fat for food processing, both when we make the food and when our body digests and uses the food. There’s the problem.

Our body sort of thinks that the partially hydrogenated fat is saturated fat because it is straight like saturated fat, but since it isn’t quite saturated fat, it really confuses our bodies in ways we don’t fully understand yet. One thing we for sure knows is that it screwed up our balance of different cholesterols. Saturated fat and trans fat both raises “bad cholesterol,” and trans fat has the bonus effect of also lowering “good cholesterol.” The relationship between fat and cholesterol is another given that we should probably understand more, but I’ll save that for a future post. (I bet you probably didn’t know, or forgot, that cholesterol is a steroid, and that steroids are hormones, and that hormones are lipids, i.e. fats. It’s more complex than that, but they are all related.)

Trans fats are so bad that, unlike regular saturated fats, there is no recommended maximum. Just don’t eat it, or as little of it as possible. That’s why the US now requires that food labels include trans fat in addition to saturated fat and total fat. So look for 0 grams trans fat on the labels and you are set, right? Not quite. There is a catch. The USDA allows manufacturers to round to the nearest 500mg, or half gram. As long as a food has less than a half gram of trans fat per serving, they can put a big zero on that line, even if there is partially hydrogenated oil listed in the ingredients list.

What it comes down to is: look for partially hydrogenated oil in the ingredients list. If it is there, there is trans fat, regardless of what the nutritional information says. And you’ll be surprised how much food has this ingredient once you start looking for it. If you are like me, you’ll find yourself buying fewer and fewer processed foods.


29 Comments so far
Leave a comment

Cool! Thanks for the explanation. I was wondering about that.

Comment by Alexajetset

Thanks! I am glad it was useful!

Comment by Lauren

fabulous post. I have been looking for something simple like this to share with my clients!

Comment by Meredith Sobel

wow this was useful info thank you very much

Comment by nacho buisness

Thanks for the explanation! I was snacking on a can of trail mix as I read this and it boasts on the front of the can “0 Trans Fat!” and when I looked at the ingredients I saw exactly what you said “partially hydrogenated cottonseed and/or soybean oils” 😦

Comment by John

Im going to DIE!


Thanks so much! it was really helpful

Comment by Brook

Salt and vinegar pringles are safe! 🙂 I just checked the ingredients list.

Comment by rachel

great explanation. your blog shows up near the top when you google “why is trans fat bad”

Comment by a

The post were very helpful and well understandable. very interesting and to the point. thanks!

Comment by joseph davis

I don’t think that MOTD could of broken done “Why is Trans Fat Bad” so eloquently yet simple. Most explanation I found before yours were very complex. The information you provided is very helpful and can save a lot of lives if people only knew. These manufacturer are masking a deadly weapon (Trans Fat) by putting 0g on the nutritional facts. Fortunately, people who knows better can look for partially hydrogenated in the indgredients sections.
Thank you.

Comment by Sabrina

Thank you so much! Im still young and I didnt know just how bad Trans fat truly is. Now I know that all the fast food places are just plain out liars! They advertise “0 grams trans fat”. Now I know better. Thanks again!

Comment by Nicolle

After being in use for awhile, it became clear that trans fatty acid had one strong drawback for our health. It raises our cholesterol, or rather it raises our bad cholesterol and lowers our good cholesterol. This can increase our risk for strokes, heart disease, and heart attack.

Comment by Trans Fats Health


Comment by Bill

I’m a little confused about the “saturated fat” issue. In the 1800’s everyone was consuming saturated fats and yet in 1900 heart attacks & heart disease was extremely rare…so much so that the average doctor didn’t know how to treat it.

Dr. Paul White (the cardiologist who treated president Eisenhower) opened his practice in 1921 and said that he didn’t treat his first heart disease patient until 1927.

According to government statistics the population of the U.S. in 1930 was 127,000,000 and there were 3000 heart attack deaths recorded that year. Odds of dying of a heart attack that year: 42,000 to 1.

And remember, in 1930, 80% of the male population were cigarette smokers.
In 1960 the population was 197,000,000 and there were 500,000 heart attack deaths that year. That’s something like 394 to 1.

If saturated fats are the culprit shouldn’t the death toll from heart attacks have been on a biblical-plague level in the early 1900’s (instead of the 1960’s) when everyone was consuming saturated fat? Why is it that the death toll rose when everyone started to switch to a “healthy diet”? Low fat this, low fat that, cooking oils, etc.

Comment by Jeff

Thank You very helpful, but my new questio is, “is any oil save to cook with.”

Comment by Remi

I am eating a slim Jim with 5g of saturated fat, 0.5g of trans fat, and 13g of total fat. A stick of pure evilness o.o. Only good thing is that there’s no sugar. Plus hydrogenated oil isn’t listed on the ingredients. Wow, I’m scared to eat any more of this stuff now, haha. Thanks for the info!

Comment by Jul

Well, I’ve heard saturated fat isn’t bad. I mean the body uses it at times. Plus the fact people have been eating meat that has saturated a long time ago and there seemed to be no problems. Guess it is just the fatties who eat a lot that make it seem bad.

Comment by cool

Oh and there is natural trans fat. Forgot what it does. But I heard it isn’t bad at all. Maybe one day people won’t be so stupid.

Comment by cool

[…] FoodFight – Why Trans Fat is Bad […]

Pingback by Are You “Gourmet”? (and Why You Should Be Cooking From Scratch). « jadedandhungry

Hi! I linked to this on my blog. Thanks!

Comment by jadedandhungry

[…] FoodFight – Why Trans Fat is Bad […]

Pingback by Are You “Gourmet”? (and Why You Should Be Cooking From Scratch). | Jaded and Hungry

I just wanted to mention another thing. Trans fats are very hard for the body to break down. Your body will start consuming muscle about the same time it will burn trans fats. So the only way to get rid of them is to starve yourself. An answer to the health food craze that led to an increase in heart disease. That’s because margarine became popular and that was filled with trans fat. As you know trans fats are super bad for your cholesterol. However saturated fats are not as bad as they seem. Yes they are harder to break down but in some ways they are better than your healthy oils. Butter doesn’t go rancid as fast as other polyunsaturated oils. Other than trans fat content, it’s really rancidity that’s the killer. I can’t explain it all but the reason I know this is because I’m doing research in this particular area

Comment by Andy

Cholesterol is a very familiar medical term almost to anyone, particularly the middle age group. It is a common thing the word will never be a part of teen-age lingo. The main reason is, most of the dreaded ailments accompanying “high cholesterol” levels are associated with hypertension, heart failure, diabetes and other long term and acquired conditions, which does not could also happen to younger generation as juvenile complications. To make it clear, when the majority is talking about lowering cholesterol, it is all about alleviating the further progress of bad cholesterol.There are two kinds of cholesterol accumulating or present in the human body. .

Remember to look out for our web-site

Comment by Lyman Justine

Cholesterol is not a steroid. It is the precursor for all steroids.

Comment by Hass

I’m a bit confused by some of your descriptions. In the third paragraph, you say that they (I assume you are referring to the food manufacturers) take the bent fat in the oil and straighten it out. I think you are referring to the cis-saturated fats that are in the oils? Not the unsaturated fats in the oils (since many vegetable oils have a combination of unsaturated and cis-saturated fats.). The way it is worded is a little confusing. The unsaturated fats aren’t in the bent (cis) formation.

Comment by Lynda

Sorry, about my previous comment. I was mixing up double bonds and sat vs unsat.

Comment by Lynda

Fantastic site you have here but I was curious about if you knew of
any community forums that cover the same topics talked about here?
I’d really like to be a part of community where I can get comments from other
experienced individuals that share the same interest.
If you have any suggestions, please let me know.

Comment by Review of Allied Schools

this is trash

Comment by avery smith

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