Fat is the star macro of the ketogenic diet. Eating high amounts of healthy fat foods is what allows you to enter ketosis, thereby burning ketones — rather than glucose — for energy.
For decades, fat was considered detrimental in promoting health and wellness, leading to low-fat dietary guidelines. Today, new research shows fat is not only a necessary component of any healthy diet, but helps promote weight loss, improves brain function and prevents a variety of diseases.
While studies have debunked the “Fat makes you fat” myth of the 1970s to 1990s, that is not to say all fat is healthy. There are good fats and bad fats; below, you’re going to learn about each of them.
There are two broad categories of healthy fats: saturated fats and unsaturated fats. Unsaturated fats are further broken down into polyunsaturated fats and monounsaturated fats. You’ll learn the definition of each below.
Most foods contain a combination of saturated and unsaturated fats. They are categorized below by the fat that takes up the majority of its contents.
Saturated fats are solid at room temperature due to their chemical structure being saturated with hydrogens and having no double bonds. Most saturated fats come from animal sources, including steak, bacon, chicken and eggs.
There used to be a prevailing assumption — made by the American Heart Association — that saturated fats cause high cholesterol, clogged arteries, poor heart health and a host of other health problems.
Recent studies have debunked this, showing no significant link between saturated fats and the risk of heart disease[*].
In fact, there are many benefits of including healthy saturated fats in your diet. Saturated fat improves HDL and LDL cholesterol levels, maintains bone density, boosts the immune system and supports the creation of important hormones.
Sources of Healthy Saturated Fats
Saturated fats were once thought to cause heart disease, but new research has debunked this long-standing myth of the 20th century. Some of the most nutrient-dense foods you can consume on keto are made up of saturated fats, including grass-fed meat, coconut oil and MCT oil.
Medium-chain triglycerides (MCTs) are mostly found in coconut oil (and in small amounts in butter and palm oil), but can also be taken in supplement form. MCT oil can be digested by your body very easily. When eaten, it is passed directly to your liver to be used immediately for energy, making it your body’s preferred fuel source in ketosis. MCTs are also great for fat loss and athletic performance.
Coconut-derived products including coconut flour, coconut oil, coconut flakes and coconut butter are excellent sources of saturated fats. They are a great dairy substitute for those who cannot tolerate it. A quarter cup of coconut flour contains about 120 calories, 10 grams of fiber, 6 grams of net carbs and 4 grams of protein. Coconut is also rich in key vitamins and minerals, including manganese, calcium, selenium, phosphorus and potassium.
Grass-fed butter is an ideal condiment and cooking fat on keto, and is also the star ingredient in bulletproof coffee. Grass-fed and finished butter is a great source of butyrate, also known as butyric acid. Butyrate is a compound that has a bevy of health benefits: It’s the preferential energy supply for colon cells, fortifies gut health, prevents cancer and improves insulin sensitivity[*][*][*][*][*].
While grain-fed cows feed on corn and soy products, grass-fed cows will live their whole life on a pasture and forage diet[*]. Grass-fed meat contains fewer calories, more omega–3 fatty acids and more conjugated linoleic acid (CLA) than grain-fed beef. CLA is known for its beneficial effects in the prevention as well as treatment for several diseases like obesity, diabetes and cancer[*].
Unsaturated Fats: MUFAs and PUFAs
Unsaturated fats are liquid at room temperature. They are divided into two categories: monounsaturated fatty acids (MUFAs) and polyunsaturated fatty acids (PUFAs). Monounsaturated fatty acids contain one double bond, which makes them liquid at room temperature, while polyunsaturated fats contain several double bonds in their chemical structure.
Sources of Healthy MUFAs
Unlike saturated fats, monounsaturated fatty acids (MUFAs) have been accepted as healthy for many years. Many studies have linked them to health benefits related to good cholesterol, better insulin resistance, reduced belly fat and reduced risk of heart disease[*].
Extra Virgin Olive Oil
Popular in Mediterranean cooking, olive oil is loaded with healthy monounsaturated fats. Olive oil also contains vitamins E and K. It’s packed with antioxidants which can help fight a variety of diseases[*].
Olive oil should be reserved for cool uses only (salad dressings) rather than for cooking. Unsaturated fats are prone to oxidation when heated, which causes the creation of free radicals and oxidative stress.
Avocados and Avocado Oil
Avocados are the one fruit you can enjoy in abundance on the keto diet. Avocados are filled with dietary fiber, potassium and magnesium. They also contain vitamins A, C, E, K and B. In some studies, avocados were shown to support cardiovascular health, weight management and healthy aging[*]. Avocado oil is one of the few natural resources abundant in the compound beta-sitosterol, a phytosterol that has been shown to inhibit the division of cancer cells[*].
Almond-derived products, like almond meal, almond flour and nut butters, is common in keto recipes as a substitute for wheat flour. One cup of almonds contains 24% of your daily values of iron, the most common nutritional deficiency and the lack of which is the leading cause of anemia[*].
Because of the high fiber and healthy fat content, almonds are believed to benefit cardiovascular health and reduce the risk of diabetes. They also help decrease inflammation and oxidative stress[*].
Sources of Healthy PUFAs
Like MUFAs, PUFAs are liquid at room temperature. They contain essential omega–6 and omega–3 fatty acids, which have healthy benefits when consumed in the proper balance. You should consume a 1:1 ratio of omega–3 and omega–6 fatty acids, but unfortunately, many Western diets consume 10 times the amount of omega–6s to omega–3s. The right balance can reduce the risk of heart disease, stroke and other diseases related to inflammation while also aiding in brain health.
Flaxseeds and Flaxseed Oil
Two compounds make flaxseed unique: ALA and lignans. ALA is a short-chain, essential fatty acid, reported to benefit various health conditions, including cardiovascular disease, hypertension, atherosclerosis, diabetes, cancer, arthritis, osteoporosis, autoimmune and neurological disorders[*][*].
Flaxseed contains more lignans, an antioxidant, than any other plant on earth[*]. Lignans have been shown to reduce the growth of cancerous tumors, especially those in breast, endometrium and prostate cancer[*].
Chia might just be one of the healthiest foods you can find. They are a great addition to your keto-friendly morning smoothie.
A single ounce contains 4.4 grams of protein, 30% of your daily magnesium and 18% of your daily calcium. Plus, while they contain 12 grams of carbohydrates, their high fiber content leaves these little seeds with just 1 gram of net carbs. Finally, they are a good source of healthy omega–3 fatty acids[*].
Fatty Fish and Fish Oil
Fatty fish, like salmon, have numerous health benefits. When selecting fish at the store, be sure to select wild-caught salmon whenever possible. Fatty fish contain two particular types of omega–3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). DHA helps improve brain development and function[*].
Unhealthy Fats to Avoid
Partially hydrogenated oils and hydrogenated oils, also known as trans fats, were created in the early 1900s as a way to make unsaturated fats shelf-stable and solid at room temperature.
Hydrogenated and Partially Hydrogenated Oils
Hydrogenated and partially hydrogenated oils are found in processed products like cookies, crackers, margarine and fast food. The vegetable shortening Crisco was the first manufactured trans fat. Trans fats are very damaging to health because they promote inflammation and increase the risk of diseases such as heart disease and cancer. Trans fats also reduce good (HDL) cholesterol while increasing bad (LDL) cholesterol.
There are some trans fats that exist naturally. These can be found in grass-fed meats and natural, high-fat dairy products like full-fat yogurt, cheese and butter; but are not the same nor harmful like the trans fats mentioned here.
Processed and Heated Oils
Many extracted vegetable and seed oils are high in omega–6s, which promote chronic inflammation. They are typically made from GMO seeds. These include corn oil, peanut oil, canola oil, grape seed oil and soybean oil.
Stick to Healthy Fat Foods on Keto
Healthy fat foods provide various health benefits and help you get into ketosis. Stick to good fats like saturated fat, MUFAs and PUFAs when you’re choosing what foods to eat.
Eat high-quality saturated fats from animal sources and unsaturated fats that aren’t processed, with an extra focus on good sources of omega–3s. Avoid processed trans fats, low-quality oils or heated polyunsaturated oils.
For more information on how to incorporate healthy fats into your diet, click here to get a free healthy fats recipe book.
Dr. Anthony Gustin is a board-certified sports chiropractor, functional medicine practitioner, entrepreneur, podcast host, and founder of Perfect Keto.
After growing his sports rehab and functional medicine clinics to six locations in San Francisco, he shifted his mission to help as many people as possible achieve optimal health and well-being.