Questions abound when it comes to fats and oils. And rightly so. This is a loaded topic that isn't exactly quick to discuss. I have to admit that my nutrition-nerd brain got the best of me a few times while writing this, but I hope you'll find a small biochemistry lesson isn't too scary. I keep things simple, but I want you to be aware of the processes that go on within our bodies.
The benefits of healthy eating really come to light when we discuss what happens after we've cleaned our plate.
Fat Metabolism
When we consume fats, there are a multitude of metabolic processes that occur. Once fat enters the body, the active components are known as fatty acids. Two organs – the liver and adipose tissue (fat tissue) – are involved in fat metabolism. Some fatty acids are transported to the liver where they are converted to glucose (a more complicated process, but the end result is glucose).
Most tissue and organs within our body can use fatty acids for energy. In fact, the heart muscle actually prefers fuel from fatty acids. They are also used in the transmission of nerve impulses, forming the structure of our cells and other tissues, appropriate blood clotting, and carrying materials, such as fat-soluble vitamins (A, D, E, and K).
However, when consumed in large and frequent amounts, excess fatty acids are taken from the liver to be stored in adipose tissue. We need adipose tissue to insulate our organs and maintain overall body temperature, but excess amounts of stored fat can lead to many health issues.
Fat should make up 20 – 35% of our daily calories, carbohydrates should be between 45 - 60% and protein 20 - 35%. It’s important to take a moment to address the importance of carbohydrates in fat metabolism. Although the use of fatty acids for fuel is just fine in small amounts, if adequate carbohydrates are not consumed (very low-carb diets or ketogenic diets) larger amounts of both fat and protein are broken down for fuel. When previously stored fatty acids are needed for energy, they are oxidized. Ketones are a byproduct of this process. A similar relationship exists between protein and carbohydrates. High fat, high protein diets typically go hand in hand. High fat intake is required when eating very low-carb to prevent the breakdown of protein for energy, a process that takes amino acids away from important tissue building and repair. This complex metabolic state is not ideal and leads to overall stress within the body. Symptoms like fatigue, weakness, dehydration, and light-headedness can result in the short term, and long term effects include increased risk of osteoporosis and metabolic acidosis.
Diabetes, heart disease, and certain cancers are associated with high fat diets.
Types of fat
Trans Fat
Basically, the devil in fat form. An un-natural byproduct of forcing a fat that is naturally a liquid at room temperature into a solid form. This process is known as hydrogenation and it reeks havoc on vegetable oils. You may see this on an ingredients list as “partially hydrogenated oil.” Most of the sources of trans fat today are fast food items like French fries and processed food items like pastries and cookies. Trans fat dramatically increases the risk of heart disease by raising cholesterol levels, specifically LDL, and creating inflammation within blood vessels. Trans fat is also linked to diabetes, as it can lead to insulin resistance. There are NO health benefits to trans fat and there is NO safe level on consumption. For this reason, US officials are moving forward with a ban on trans fats. This will prevent all food manufacturers from using these fats in their food items – something that is long overdue. Read labels for now to ensure you aren’t consuming this stuff.
Saturated Fat
When Time featured the “Butter is Back” cover story in June 2014, controversy and confusion ensued. Many breathed a sigh of relief. Who doesn’t want to be told that eating a high fat, palatable food is OK, after all? But most of this article and the studies referenced were filled with holes and poor research. I won’t go into too much detail here, for sake on staying on topic, but Dr. David Katz wrote a wonderful article that outlines said holes and you can read it here.
“Notably, when saturated fat calories from the customary sources — bacon-cheeseburgers, Reuben sandwiches, and pepperoni pizza come to mind — are replaced with either unsaturated fat (from nuts, seeds, olives, avocado, and fish), or with calories from whole grains — rates of cardiovascular disease decline significantly.”
When it comes to saturated fats, we should understand that this is really a broad category for many different fatty acids. And not all are created equal. We do seem to know, with relative certainty, that if you have high cholesterol or if you are at risk for high cholesterol, any type of saturated fats should be limited, even coconut oil. However, if your cholesterol is within normal range, a small amount of saturated fat in the diet, from plant sources, shouldn’t be a problem. In fact, research shows that our bodies respond with less inflammation when we consume plant-based saturated fats as compared to animal sources.
Polyunsaturated Fat & Monounsaturated Fat
These are the fats that should make up most of our calories from fat. Most of these fats come from vegetable or nut sources, provide essential fatty acids, and are linked to lower risks of chronic diseases.
The two essential fatty acids are omega-3 fatty acids and omega-6 fatty acids. Both can be found in many plant sources:
- Omega-6 fatty acid: Nuts, whole grains, vegetable oils
- Omega-3 fatty acid: flaxseed, hemp seed, walnuts, chia seed, seaweed, beans, leafy greens, cabbage, berries
It is much easier to get enough omega-6 fatty acids in our diet, but it remains a concern that many Americans are not taking in adequate omega-3’s. Both Omega-3 and omega-6 fatty acids come in different forms, some easier to consume in our diets than others. Check out this article from Dr. Michael Gregor on how our bodies handle the various types of omega-3 fatty acids along with current recommendations.
Oil
One of the most common questions I get is “What oils should I be using for cooking?”
This is a great question and it’s important to understand that cooking temperatures are a big deal when it comes to oils.
Saturated fat oils and refined oils are the most stable at higher temperatures. These oils shouldn't be consumed in large amounts for the reasons mentioned above; cooking with small amounts is ideal.
Un-refined, or virgin, oils tend to be less stable at even low temperatures and are best when served raw or on food that has been removed from heat. These oils often contain the most essential fatty acids and other beneficial nutrients. If cooking with these oils, be sure to always heat below the smoke point. When oils smoke, they are oxidizing, which creates free-radicals that can lead to health concerns.
Rancid oil is another thing to consider. If oils are exposed to light, heat, and air too frequently, they will become rancid. This is oxidation rearing it's ugly head again. To prevent this, keep oils in sealed containers, choose dark glass over plastic, and store it in a cool place in your kitchen. If your oil has a funky, clay-like smell or tastes like rancid nuts, you have a problem. That oil is past expiration and it's time to buy more. If you don't use a specific oil very often, like sesame oil, make sure to buy in small amounts so you will go through it in a timely manner. Costco isn't always best when it comes to oils.
Take a look at the chart and guide I have created to guide you in consuming oils and fats.
Link not working? Download the PDF Guide for 'Cooking with Fats and Oils'!
I'll be posting some recipes soon that involve "no oil" cooking methods. It's actually a lot less complicated than it sounds. I hope you've enjoyed this information and please comment with any questions! Peace.
