Continuing our theme with National Nutrition Month, I wanted to talk a bit about dietary fat. There’s a lot of confusing information about what is good fat, what is bad fat, what should you avoid/reduce/eliminate from the diet, etc. So I dove into some good old-fashioned data mining.
Most of this info is from articles in PubMed, the National Institutes of Health searchable archive of published research. For some of the high-level overview stuff I checked with WebMD as well. Hey, even docs visit WebMD sometimes!
Before I start talking about the different kinds of dietary fats, I want to make sure you all know that you NEED fat in your diet. Your body needs good fats, the essential fatty acids that can’t be produced in your body. Also, fat helps you absorb vitamins A, D, E and K from your foods.
There are two main types of fat in the diet, saturated and unsaturated. Saturated fats are solid at room temperature and unsaturated fats are liquid oils. Typically people eat some of each type. People usually believe that oils are good and solid fats are bad. This is actually an oversimplification: there are good and bad elements to both types of fats.
First up are the oils. The essential fatty acids are polyunsaturated fats called DHA, EPA and ALA, also called omega-3 fatty acids. ALA can be converted to DHA and EPA in the body, although our cells aren’t very efficient at it. ALA is found in flaxseed oil, canola oil, soybean oil and walnuts. DHA and EPA are found in fatty fish (wild fish have higher levels than farm-raised fish) and also made by algae.
Other mono and polyunsaturated fats are found in other oils such as olive, peanut, safflower, sunflower, sesame and corn oils. They are safer choices than animal fats in general.
The saturated fats in general should not be eaten to any significant extent. The exception, however, is a substance called medium-chain triglycerides (MCTs). These are fats that are rapidly metabolized in the liver rather than being stored in fat tissue. They have been shown to promote satiety, making you feel full faster and longer. They also seem to increase calorie expenditure after eating them and may have a role in promoting weight loss. The richest dietary source of MCTs is, interestingly enough, coconut oil. About 50% of the fat in coconut oil is in the form of MCTs. Two other good dietary sources are butter and palm kernel oil.
Lard. Sausage. Bacon grease. That yummy marbling on your steak or the layer of fat on the outside of your roast. DON’T EAT THAT!!
The consumption of animal fat should be limited. It throws your cholesterol out of balance and may promote hardening of the arteries. If you’re going to eat meat, eat lean cuts of pasture-raised (also called grass-fed) beef and free-range poultry, which have much higher levels of omega-3 fatty acids than typical grain-fed animals.
Now I want to tell you about some dangerous fats that you should avoid whenever possible. First I want you to go get 3 boxes out of your pantry. Cereal, crackers, cookies, whatever. Also, get your margarine out of the fridge.
Now look at the ingredients list. If there is anything in there that says “partially hydrogenated” please throw that away. Hydrogenated and partially hydrogenated oils are man-made fats that were chemically altered to “harden” them and extend their shelf life. They are very pro-inflammatory and should be eaten in very limited amounts if at all, especially if you suffer from heart or vascular disease, fibromyalgia, joint or back pain, or chronic fatigue.
Next look at the nutrition panel. Look at the “trans fat” line. Trans fats are a type of partially hydrogenated fat that not only raise LDL (bad cholesterol) like saturated fat but also lower HDL (good cholesterol) and may be even worse for your health. Food manufacturers are allowed to say their product is “trans fat free” if there is less than 0.5 gram per serving. However, if you see “partially hydrogenated” in the ingredients there are trans fats in there, no matter what the nutrition panel says.
Lastly I’d like to say a few words about genetically modified food crops. In the USA it is difficult to find corn that is not genetically modified. Soy, canola and cotton are also widely genetically altered. Unfortunately the USA is not requiring (yet) the labeling of genetically modified foods, and there were no long-term safety studies done before the genetic alteration of food crops was permitted. The USA is one of the only industrialized countries in the world which does not require labeling of genetically modified foods.
If you want to avoid genetically modified foods (and I’d say it’s a good idea) as of now there are only a few options. First of all, buy organic, as organic foods cannot have genetically modified ingredients. Second, you can buy products labeled “non-GMO” which are not organic but also can’t contain genetically modified ingredients. Lastly you can avoid the four most commonly altered food crops above.
There are four common scenarios where fat is added to foods: high-heat frying, low-heat sauteing, baking and as dressings. There are specific recommendations for each situation.
For high-heat frying (which you shouldn’t be doing a lot, anyway) your best fats are butter and coconut oils. They tolerate high heat the best without breaking down, and they contain medium-chain fatty acids which can help you eat less of those foods you’re frying 🙂
For low-heat sauteing, olive oil or sesame oil are your best bets. Olive oil and nut oils (like sesame or walnut) also are excellent choices for dressing salads.
When you’re baking, you have a choice between lard, butter and margarine. (Lard, ew. No, thanks.) My recommendation is to go with the butter, because it is unprocessed (i.e. does not have artifically hydrogenated fats) and, like with frying, has the medium-chain triglycerides which increase the metabolism and tend to be burned rather than stored. Remember to limit your intake of the baked goods though! Give away your Christmas cookies!
Remember, food should come from the farm and the field, not the factory and certainly not the lab! Try to choose the most unprocessed options you can, and you’ll be rewarded with better health 🙂