Why Are Trans Fats Bad

A reader from the UK, living in Canada now, recently wrote to me asking why North Americans seemed to be so much more tolerant of trans fats than Europeans and Brits. Apparently across these pond fats are as good as gone from their foods as people refuse to buy them otherwise.

So where’s our resolve? The fact of the matter is, I don’t know why we North Americans wouldn’t be more like our neighbors to the east. It seems that we are aware of the trans fat and know that they’re bad, but when it comes to staying clear of them we fall short.

Maybe we’re waiting for someone to do our work for us. We figure that if these fats were all that bad the government wouldn’t allow them in our food supply. Maybe we’re waiting for the precedent set by New York City to carry on to effect us, too. Calgary followed suit in the beginning of this year being the first Canadian city to ban the use of trans fats in restaurants. How long before your home town follows suit? Can you afford to wait?

If we really are just waiting for a ban, it’s truly a sad state of affairs. What happened to taking responsibility for our own health? In response I will do the only thing I know how to do – educate my readers and hope that they make the right decision for the good of their health.

So what is a trans fat, anyway? Well, they are molecularly similar to natural fats with one difference – their double bonds are in the trans formation instead of the natural cis formation. Rather than get into the molecular structural differences, I’ll just leave it at this – cis fatty acids your body knows how to deal with; trans it doesn’t. (If you’re interested in learning more about their chemical structure the wikipedia entry has diagrams and an excellent explanation). The inability of our bodies to metabolize these mutant fats is suspected to be the reason they cause health problems.

cis configuration double bondtrans configuration double bond

So where do they come from? The majority of trans fats in the human food supply come from the hydrogenation of unsaturated vegetable fats. Hydrogenation is a form of processing where they take a liquid unsaturated fat and apply pressure and heat and blast it with hydrogen thus turning it into a semi-solid fat.

Why would anyone want to do this? Mainly, as you could have guessed, because hydrogenated fats are cheaper than their natural couter-parts. But also to increase shelf life of fat containing products (which normally go rancid rather quickly) and to get a fat that behaves like a saturated fat (semi-solid at room temperature, high smoke point for deep frying) without actually being a saturated fat. Back in the 1950’s when everyone started trying to eliminate saturated fats from their diets, the processed oil industry managed to convince us all that this heavily processed, hydrogenated fat was better for us than saturated fats like palm oil, coconut oil and even lard. Hence the introduction of margarine as a replacement for natural and delicious butter.

And what’s so bad about trans fats? For starters, the medical community is in pretty much full agreement that trans fat consumption drastically increases the risk of Cardiovascular Disease (CVD). Although the numbers differ from study to study, the Nurses’ Health Study found that replacing 2% of food energy from trans fats with food energy from non-trans unsaturated fats decreased the risk of CVD by 53%!

As if this weren’t enough, the fats are also suspected of causing obesity, type II diabetes, high blood pressure, liver dysfunction, rheumatoid arthritis, ADHD, depression, chronic fatigue syndrome, infertility and even cancer.

So how do I avoid them? Read your labels. Look for anything that says “hydrogenated”, “partially hydrogenated” or “shortening” and avoid it like the plague. But remember – any product with less than 0.2 grams of trans fats per serving can be labeled as “trans fat free” here in Canada. Considering the fact that any trans fat in the diet is considered detrimental to health this seems like a license to lie to the consumer. Don’t believe these labels that say trans fat free – read the ingredients. Further, assume restaurants are using hydrogenated oil unless you know otherwise. Don’t be afraid to ask. Also, assume that unlabeled baked goods contain trans fats. Most bakeries use hydrogenated shortening and will often state it proudly if they’re not (look for “made with real butter” signs and taste the difference).

But of course, the best way to avoid these fats is to cook what you eat yourself.