Restaurant Ban on Hydrogenated Oils Is A Good First Step
Los Angeles recently instituted a program where restaurants could voluntarily ban hydrogenated oils from their menus and receive a "trans fat free" designation from the city, after being subject to a series of unannounced inspections which turn up no offending fats on the premises. This follows a similar move in New York City, where hydrogenated oils were banned outright from restaurants in 2006, and Calgary which followed suit this year.This is a great first step, and I'm glad to see these cities are taking the incentive to care for the health of their citizens. The ban of hydrogenated oils, the primary source of trans fats, which are what make up the majority of margarines, vegetable shortenings and restaurant fryer oils, is a great place to start. But the ban also reveals how little people still know about harmful fats and how we are exposed to them.
Another major source of harmful fats which is not being addressed by the ban and which the media has yet to pick up on, is using polyunsaturated oils for cooking. Polyunsaturated oils, otherwise known as omega-3 and omega-6 fats or the Essential Fatty Acids (EFAs), are delicate fats which can easily go rancid or oxidize without proper care.
These EFAs are ones we need to get from our diets as our bodies cannot make them from other fats and yet need them for many vital processes. While they are essential to our survival and have many beneficial effects, polyunsaturated fats can become harmful trans fats, or oxidize to become more susceptible to free radical formation, when exposed to excessive heat, light or oxygen.
You read that right - the heating of most vegetable oils, as in cooking, converts them into harmful fats. So all these restaurants that are switching from hydrogenated oils to vegetable based oils are trading a bad oil for a slightly-not-as-bad-but-still-far-from-perfect oil. I know this is a somewhat complicated topic, so I've broken it down into a quick reference guide for you to use when cooking at home.
1. Avoid anything that has "partially hydrogenated", "hydrogenated" or "shortening" in the ingredients list. Even if it says "trans fat free", it still can contain up to 0.5 grams of trans fats per serving (a lot of trans fats when you consider the fact (this is based on a famous nurses study out of Harvard) just one gram of trans fat, the equivalent of 2 servings of "trans fat free" products, is likely to increase the risk of heart disease by 20 percent if consumed on a regular basis).
2. Supplementing EFAs is a good idea, but only supplement omega-3 fats, most often found in the form of fish oil or flax seed oil. Supplementing omega-6 is unnecessary as many nutritionists feel most people are already getting too much of these fats in their diets.
3. For cold food applications like salad dressings it's OK to use polyunsaturated oils (omega-3 and 6) that have been cold pressed, kept in a dark container and refrigerated. These are the fats that stay in their liquid forms when refrigerated - flax oil, corn oil, safflower, sunflower, avocado or walnut oils, for example. Note that sunflower, safflower, corn, soybean and cottonseed oils are all high in omega-6, however, so moderation is recommended.
4. For cold applications or light cooking and sauteeing you can use monounsaturated oils (omega-9). These are the oils that become a little sludgey or congealed in the fridge and need to be warmed to room temperature before they become pourable. The major one here is oleic acid found in olive oil, peanut oil, sesame oil and high-oleic versions of oils like sunflower or safflower.
5. For frying, cooking, baking and other high-heat applications, you should be using saturated fat. These are the fats that are semi-solid (although often spreadable) at room temperature. They include coconut oil, palm kernel oil, butter, lard and ghee. Note that it is saturated fats which are most often replaced by hydrogenated oils as hydrogenated oils mimic the valued properties of saturated fats (solid at room temperature, high flash point, long shelf-life).
I know these guidelines go against a lot of what we've been told over the last few decades. Although the polyunsaturated like corn oil and most other vegetable oils have been marketed as cooking oils sold in clear plastic bottles for decades, they can quickly become harmful when exposed to heat, light and oxygen. And you'd be hard pressed to find a person on the street who didn't believe saturated fat consumption leads to heart disease, even though they are the most stable and therefore least likely to become harmful when used for cooking.
What we're not told is that as oils become more saturated they become more stable meaning they can be exposed to more heat, light and oxygen without becoming trans fats. Thus olive oil, which is more saturated than, say, sunflower oil (it contains mostly omega-9 fats), can be left out of the fridge and can withstand light cooking without oxidizing, but is still preferably kept in a dark bottle. The recent work of many nutritionists, doctors and researchers is bringing to light the fact that our blame for heart disease and atherosclerosis on saturated fats has been misplaced and that trans fats and the misuse of polyunsaturated fats have been the culprits all along.
Although recent work showing the health benefits of coconut oil are leading the way toward a better understanding of fats, I think we're still a long way from healthy fat consumption North America. The banning of hydrogenated oils in a growing number of North American cities is a step in the right direction, and we can only hope that more Canadian cities will begin to follow Calgary's lead. But until a true understanding of fat and it's proper uses versus detrimental applications is learned and applied by society at large, our ailing population will continue to find no relief. 
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