Trying to figure out what fats to eat is challenging. After years of low-fat diet trends where people swapped eggs and butter for egg whites and partially hydrogenated oils we live in a society where people are overly sensitive about fat and would rather eat food-like products than real, nutrient-dense foods. Even though the literature tells us that fat does not make you fat, people are still afraid of it. This is due in large part to that fact that some of the biggest industries in the nation will lose if fat-centric becomes mainstream to the current fat-phobic way of thinking.
Fat doesn't make you fat. While it is technically possible that overconsuming dietary fat would lead to increased adipose tissue, logistically that would be very hard given that fat is very filling and satiating.
When you eat fat, your body processes it more slowly than it processes carbs/glucose. This means that fat stays in your stomach longer and makes us feel fuller for longer. Carbohydrates and sugar, on the other hand, are easy to overconsume because they do not trigger the same satiety response as fats. They are a source of quick burning fuel and do not do a good job of keeping our bodies going for the long-term.
What are fats?
Fats, or lipids, are made up of chains of carbon, hydrogen, and oxygen. There are two forms of fats: oils, which are liquid at room temperature, and fats which are solid at room temperature. Fatty acids are the individual chains that make up the fat molecule. Remember back to high school biology? The membranes of every cell in your body is made up of fat molecules (lipid bilayer!).
- Transport nutrients
- Are the building blocks of hormones
- Play a role in immune function
- Help with the absorption of fat-soluble vitamins (A, D, E, and K)
- Insulate nerve fibers and brain cells
- Help regulate metabolic function
All Fats Are Not Created Equal
There are three major types of fat and they are all found in all foods in varying ratios:
- Monounsaturated fat
- Polyunsaturated fat
- Saturated fat
Due to the chemical structure of monounsaturated fats (for those of you that are science nerds, they have double bond between two chains), foods with a high ratio of these fats are liquid at room temperature. The chemical structure also makes it relatively unstable and susceptible to oxidation when exposed to air, light, or heat (have you ever wondered why olive oil usually comes in a dark colored container, this is why).
Foods that contain the highest ratio of monounsaturated fat include macadamia nuts, avocados, and almonds. Beef, pork, and chicken are also technically monounsaturated fats due to the fact that more than half of the fat found in these foods is monounsaturated fat.
Real Food Recommendation: Eat lots of monounsaturated fats as their whole food sources. Use monounsaturated oils (avocado, olive, almond, hazelnut, and macadamia nut oil) for cold uses (salad dressing!) or very low-heat cooking. Choose cold-pressed and/or extra virgin sources. Protect these oils by keeping them in an opaque glass container and/or in the fridge.
Due to the chemical structure of polyunsaturated fats (more than one double bond), foods with a high ratio of these fats are always liquid at room temperature and are very unstable and susceptible to oxidation.
The two most commonly known polyunsaturated fats are omega-3 fatty acids and omega-6 fatty acids, both of which are essential fatty acids (meaning that our bodies don't make these on their own). Omega-3 fats are good at fighting systemic inflammation and supporting brain function. They may also play a role in reducing symptoms of depression and some autoimmune conditions.
Real food sources of omega-3s come from wild fish (salmon, sardines, and cod), grass-fed and pasture-raised meats, eggs, and some nuts and seeds.
Omega-6 fats help brain function, support the immune system, and help with overall growth and development. They can be found in a wide variety of foods including grains, nuts and seeds, vegetables, and meats.
The key with omega-3 and omega-6 is balance. Omega-6s help stimulate inflammation and omega-3s fight it. So when you get out of balance and have too much omega-6, you end up with inflammation. Processed grains, vegetable oils, and factory farmed meats are all high in omega-6 fatty acids.
A good rule of thumb to keep in mind is that there are no "bad" fats in nature. It's the unbalanced amounts of omega-6 fats that have found their way into our diets that cause some problems. Sara of ThePaleoMom.com talks about the ratio of omega-3 to omega-6 fats in an ancestral diet (1:1 or 1:2) vs that in a modern Western diet (1:10 to 1:40). Inflammation means an increase in all inflammatory diseases - cardiovascular disease, cancer, asthma, Alzheimer’s, autoimmune conditions, diabetes...you get the point.
Conventional polyunsaturated oils that are commonly used in cooking go through a high heat processing and have to be degummed, bleached, and chemically deodorized before getting packaged for sale. This means that the clear bottle of canola oil sitting in the grocery store, or the soybean oil used to cook your french fries at a restaurant has been exposed to a lot of heat, air, and light and is a oxidized (i.e. damaged). Also, who wants to eat something that had to be degummed, bleached, and deodorized before it was fit for consumption?
Oxidized fats are not at all good for your body. The free radicals cause damage and inflammation inside your body, and is linked to cancer, major degenerative diseases, heart disease and even wrinkles.
Real Food Recommendation: Eat whole food sources of omega-3 fats like wild-caught fish, pasture-raised meats, and eggs. Reduce your consumption of omega-6s by removing processed grains from your diet. Avoid all polyunsaturated oils (canola, soybean, cottonseed, corn, vegetable, grapeseed, sunflower, safflower, sesame, peanut, and rice bran oil). Do not cook or bake with polyunsaturated oils and don't purchase processed foods with polyunsaturated oils in the ingredients. Cold-pressed polyunsaturated oils that haven’t been exposed to heat like sesame oil (not toasted) or rice bran oil are ok for cold uses.
The chemical structure of saturated fats (no double bonds) allow the molecules to pack closely together and are solid at room temperature (they are saturated with hydrogen atoms). These fats are more stable than other forms of fat and are not very susceptible to oxidation even when heated to high temperatures.
Saturated fats contain lots of vitamins like A, D, K2, and B12 which are very deficient in our society. They also help raise HDL cholesterol which we need to fight inflammation. This is the real reason behind blood cholesterol increasing (low HDL levels and lots of systemic inflammation). Natural sources of saturated fats include coconut oil and butter.
Traditionally doctors have said that you should keep your intake of saturated fat low in order to reduce your risk of heart disease. However, there are couple of important things to remember here. 1) most doctor’s don’t have much nutritional education (I think they average about 8 hours of education on nutrition in medical school). 2) for some reason this information seems to simply be “common knowledge” not actual scientific research.
According to an article by David Katz, MD it seems very likely that the "harm" caused by saturated fats are "compounded by the company they keep." For example, there is evidence that processed meats are more clearly linked to poor health outcomes than plain beef or pork. There is also evidence that fat was never the "lone dietary peril' and that excess calories, sugar, refined starch, etc. are equally dangerous.
A meta-analysis of studies that evaluated the association of saturated fat with cardiovascular disease found that intake of saturated fat was not a associated with an increased risk of heart disease or stroke.
In the Standard American Diet, the main sources of saturated fat are pizza and packaged sweets, which essentially means that a diet high in saturated fat is a diet that is high in junk. And since we know that the effects of saturated fats are compounded by the company they keep, rather than looking at a single dietary component (saturated fat), it seems more reasonable to look at some whole foods you would actually eat.
Real Food Recommendations: Eat saturated fats as their whole food sources - meats, coconut and dairy products. Use saturated fats for all medium to high-heat cooking, including pan searing or grilling. Good options for cooking fats are grass-fed butter, ghee, coconut oil, and animal fats like duck fat, lard or tallow. Make sure all sources you consume are cold-pressed, organic, and/or grass-fed if possible.
Trans fats are unsaturated oils that have been hydrogenated (where the double bonds are broken and hydrogen atoms are artificially added back into the chains). This process turns oils like corn and soybean oil into an unnatural saturated fat that’s solid at room temperature.
Real Food Recommendation: Run very far away from trans fat. Run like your life depends on it…because it does. Be sure to check labels for hydrogenated, partially-hydrogenated, or fully hydrogenated vegetable oil. If you see that it means that it contains trans fats. Also, look out for high stearate or stearic rich fats. These fats can be found in coffee creamers, baking mixes, frosting, peanut butter, crackers, baked goods, margarines, cookies, candy, salad dressings, whipped topping and more. Just stay away from them!
You might be wondering where we got the idea that fat is bad if there is evidence showing that it really isn't. Well, it's complicated. There is a mess of marketing, political, and conflicts of interest that don't necessarily have anything to do with science in this arena.
If you are interested in getting into the nitty gritty (fatty?) details of this mess, I suggest this article (the author also wrote a book) or Denise Minger's book, "Death by Food Pyramid." Gary Taubes's book "Good Calories, Bad Calories" is also an interesting (and rather dense) look into some food politics and how we got to where we are today. This paper also summarizes how we got to where we are in terms of dietary recommendations for fat.
Here's an article on healthy vs unhealthy fats along with some chemistry to help you understand why.
While it might seem scary to dive right into eating more of something you have always been told to avoid, it's OK! Remember that when we cut out processed foods we still need to get those calories from somewhere, so why not get them from healthy fats?
I don't recommend calorie counting while you are attempting to make this change (I think it has a place but this isn't it). If you are concerned about overeating, you can always tackle that after you are nourishing your body with whole foods. I think you'll be surprised and how much less you'll eat overall without trying when you start getting all the nutrients you need.
The good news is it's almost impossible to overeat fat because it makes you feel full! Generally your body will tell you it's time to stop eating well before you have eaten too much. So as long as you aren't doing shots of olive oil or eating spoonfuls of ghee, you should be just fine!
If you want all of this information summarized into one super easy to follow guide, you can download this FREE printable Guide to Fats and Oils by entering your email in the form below!
Any questions? ;)
PS. I like fat so much I put it on my face in addition to eating it!