Fat used to be a four-letter word, at least, nutritionally speaking. But we now know that fat plays an essential role in a healthy diet. We need fat to produce hormones, make strong cell membranes, help us absorb fat-soluble vitamins, and, perhaps most importantly, to make our food taste good! But the health-promoting properties of certain fats and oils can change just based on how you cook with them.
When cooking, it’s important to know what type of oil to use and when.
But from canola to coconut, there are a ton of options out there. How to choose? Let’s find out.
TYPES OF FATS
There are three types of fat: saturated, unsaturated, and polyunsaturated, and, when it comes to cooking, “The first thing you need to know is degree of saturation,” says Dr. Cate Shanahan, M.D., nutrition council for the Los Angeles Lakers and author of Deep Nutrition: Why Your Genes Need Traditional Food. This is because the more saturated a fat, the less vulnerable it is to heat damage.
SATURATED MEANS STABLE
Fats are made up of chains of carbon atoms with hydrogen atoms attached to the carbon atoms. A saturated fatty acid has a hydrogen atom attached to every carbon atom. It is “saturated” with hydrogen atoms.
You can think of a saturated fat like a chain-link fence, where all the holes are plugged with hydrogen.
This saturation creates a strong, stable barrier against light and heat. Monounsaturated fats and polyunsaturated fats, however, are missing either a pair (mono) or pairs (poly) of hydrogen atoms in their carbon chains. These fats are like fences with holes, or gaps, in them. The gaps create weak spots where the fat can become damaged if exposed to high degrees of light and heat.
MIND THE GAP
You want to try and avoid eating damaged fats whenever possible, as research shows that once inside your body, damaged fats can spark “free radical cascades,” otherwise known as oxidative damage, which has been linked to numerous health conditions. Since certain fats – those with gaps in their carbon chains – can become damaged when exposed to heat, it’s best to choose your cooking fat or oil based on the level of heat required.
COOKING AT HIGH HEAT
Methods: High-heat cooking includes pan frying, sautéing, grilling, and pan-roasting. Anything above 375°F is considered high-heat cooking.
Best type of fat: Saturated
Saturated fat is no longer the nutritional public enemy it once was. Recent research has revealed that, when eaten in moderation, saturated fat can have a place in a healthy diet. Additionally, saturated fats have been shown to suffer the least amount of oxidative damage when exposed to high heat.
Butter / Ghee
Butter is composed of butterfat, milk solids, and water. Ghee is clarified butter, or, butter with the milk solids and water removed. Both butter and ghee contain short and medium-chain fatty acids, which have been shown to support fat burning, boost metabolism, and help improve muscle function. Butter is also a good source of iodine and selenium – two nutrients that help regulate our thyroid – while the butyric acid in butter can help support digestion.
Coconut oil contains even more medium-chain fatty acids than butter. The most abundant fatty acid in coconut oil is lauric acid, which breaks down to a compound called monolaurin. Some research shows that monolaurin has antibacterial and antiviral properties (Kabara et al. 1972, Ruzin and Novick 2000, Hoffman et al. 2001)
Animal fat (pork, beef, duck)
Animal fats are about half saturated fats. The other half consists primarily of monounsaturated fats, which have been shown to help promote healthy arterial function – so don’t throw out that bacon grease! Just be mindful that animals store toxins in their fat cells. It’s important that when you eat animal products with a high fat content or cook with animal fat, that it is from a high-quality source, such as pasture-raised pork, grass-finished beef, and wild-caught seafood.
Methods: Medium-heat cooking includes simmering and reductions, and ranges from 325°F to 374°F. Medium-low heat ranges from 250°F to 324°F.
Best fat: Saturated or monounsaturated fats (MUFA)
Monounsaturated fats are only have one gap in their carbon chain, so they can withstand some level of heat – just not too much.
A favorite of chefs and healthcare practitioners alike, olive oil is an excellent source of vitamins K and E and contains the antioxidants oleocanthal and oleuropein, which have been found to promote healthy arterial function and a healthy inflammatory response.
Like olive oil, avocado oil is nearly 70% oleic acid, a monounsaturated omega-9 fatty acid, and has been shown to help support cardiovascular health and liver function. Additionally, avocado oil’s polyhydroxylated fatty alcohols may help protect skin from damaging UV light. But unlike olive oil, which has a strong taste and smell, avo oil has a mild smell, creamy texture, and can even be used in place of butter for people who can’t tolerate dairy.
While peanut oil is popular for frying, it breaks down to about 46% monounsaturated fatty acids, 32% polyunsaturated fatty acids, and 17% saturated fats. Due to this relatively high level of polyunsaturated fatty acids – which are easily damaged by heat – it’s best to keep the temperature at a moderate level when cooking with peanut oil.
Macadamia nut oil
As delicious as the nuts themselves, macadamia nut oil is buttery, rich, and makes a mind-blowing homemade mayonnaise. The only drawback can be the hefty price tag, so save this one for extra special eating occasions.
Methods: These oils are best consumed cold, drizzled on top of salads or used as a finishing flavor on cooked dishes.
Best fat: Polyunsaturated fats (PUFA)
Polyunsaturated fatty acids (PUFA) have multiple gaps in their carbon chains, making them easily susceptible to damage from light and heat. When shopping for these oils, choose brands in light-proof containers, such as dark glass bottles, and store them in a cool, dark place.
Sesame seed oil
Like olive oil, sesame seed oil is a good source of antioxidant vitamin E. It also contains vitamin K, magnesium, calcium, copper, iron, and zinc. Sesame seed oil is a staple used to flavor many Asian dishes, but since it’s over 40% PUFA, save it as a topping to drizzle over the food once it’s cooked.
Flax seed oil
Flaxseed oil is an excellent source of omega-3 fatty acids in the form of alpha-linolenic acid (ALA), which has been shown to help promote heart health and a healthy inflammatory response.
Of all the tree nut oils, walnut oil is one of the best sources of antioxidants, delivering more than 20 mmol antioxidants per 3 ounces. Walnuts are also an excellent source of omega 3 ALA and a natural source of melatonin – a hormone which helps regulate our sleep. Try swapping walnut oil for olive oil in your dinnertime vinaigrette, or adding it to Greek yogurt with berries and honey for dessert.
You’re probably not going to be drizzling fish oil over your salads, but it’s important to note that both fish and fish oil supplements are a major source of the PUFA omega 3 fatty acids EPA and DHA. These oils are highly heat sensitive, so be mindful of the temperature when cooking fish. If you are taking a fish oil supplement, make sure that the oil is extracted in a gentle way that does not involve high heat or chemical solvents. For more about the kind of omega 3 fish oil we use in SmartyPants read here.
A NOTE ON VEGETABLE OILS
The name vegetable oil is somewhat misleading as there are no oils created using vegetables (avocados and olives are actually fruits). What we call vegetable oils – canola (rapeseed), cottonseed, soybean, sunflower, and safflower – are mostly made from seeds.
Unlike a ripe avocado or juicy olive, it’s hard to squeeze oil out of a seed, so the process to create these “vegetable” oils usually requires extremely high heat and chemicals (you can watch exactly how canola oil is made here). Why does this matter? Because these seeds and soybeans consist primarily of polyunsaturated fatty acids, which are damaged by heat. In other words, these oils can be damaged, or oxidized, before they ever even hit the pan.
WHAT ABOUT SMOKE POINT?
You’re probably wondering why we haven’t mentioned smoke point. The smoke point is the temperature at which the protein, minerals, enzymes, and other compounds naturally present in oil begin to burn. This burning releases free radicals and a substance called acrolein – the chemical that gives burnt foods that nasty, acrid taste and smell. So, you definitely want to avoid burning any of your fats and oils.
But, according to Dr. Shanahan, fat can become damaged long before it starts to smoke.
Oils which have been refined, such as canola and soybean oil, have had all their proteins removed, so they have very high smoke points. But that doesn’t change their fatty-acid profile. If the oil you’re cooking with contains polyunsaturated fats, then they are damaged by heat – regardless of smoke point.
EXTRA VIRGIN? COLD-PRESSED? WHAT THA…
Okay, so, you’re in the grocery store, ready to pick your oil, when, all of a sudden, you’re bombarded with “cold-pressed,” “expeller-pressed,” “extra virgin,” “light,” etc., etc.
The single thing to look for is any term that indicates refinement, such as “light,” says Shanahan.
According to Dr. Shanahan, “You don’t need to refine something that has been extracted in a gentle way.” (You can refer back to that canola oil video…) Expeller-pressed is the same thing as cold-pressed. “Cold” refers to the product being stored at no higher than 81.9 °F, and “pressed” means that no heat or chemical additives were used to extract the oil – the olives or avocados or coconuts we’re simply pressed until they released oil. Extra-virgin means oil that is made from the first pressing, i.e. no refinement.
FOUR, SIMPLE RULES
To make things a little easier, you can remember these four tips:
- Choose your cooking oil or fat based on its degree of saturation.
- Avoid the word “light” or “refined” – go for “extra virgin” instead.
- If your oil starts to smoke, throw it out and start again.
- When in doubt, cook low and slow.
Posted on March 15, 2017