The Best and Worst Fats to Eat on the Keto Diet

Many keto diet followers swear by the trendy eating plan for weight loss, and hey, getting to a healthy weight is important. But what if, while slimming your waistline, the diet was also increasing your risk of heart disease, stroke and high blood pressure?

Unfortunately, that could be the case if you're choosing the wrong fats on this high-fat, low-carb plan.

Going heavy on the bacon and cheese may work for fat loss, but the true key to keto is eating fat from anti-inflammatory sources. Here's how to get it right.

The idea behind the keto diet is to severely restrict carbs so your body enters a state called ketosis, in which it shuns sugar and instead burns fatty acids for fuel (which are created when your digestive system breaks down the fat in your food into tiny particles for energy).

But those fatty acids do more than simply provide energy to hungry cells. They also play a role in cell signaling and gut health, which affect inflammation. Inflammation is a complex buzzword, but think of it like fire in the body: Less fire makes for a healthier human. That's why it's so important to choose the right fats to fuel your body.

Monounsaturated fat intake has been linked with improving cholesterol, lowering blood pressure and reducing overall body fat mass. In particular, consuming MUFAs from plant-derived sources provides the benefits of additional compounds, which also help to reduce inflammation.

Good monounsaturated fat sources include:

• Olive oil
• Avocado and avocado oil
• Canola oil
• Almonds
• Macadamia nuts
• Blue-green algae

Animal lard and beef tallow also contain a significant amount of monounsaturated fat in addition to saturated fat.

To incorporate more MUFAs into your keto diet, try making salad dressing at home with olive oil, cook with high-heat-stable avocado oil instead of corn or soybean oil, and add macadamia nuts and almonds to salads or snacks.

These fats fall into two categories: omega-6 and omega-3. Both types play important roles in cell signaling and are essential for health, but the ratio is important. As a November 2018 paper in ​Open Heart​ points out, reducing intake from omega-6 fats while boosting omega-3s creates a more favorable level of stress in the body. A little stress is OK, but a lot of stress is not!

​Limit Omega-6 Fatty Acids​

Omega-6 fats promote inflammation that has beneficial effects for the body, such as blood clotting, but it can quickly become too much of a good thing. Omega-6s break down into arachidonic acid, a fatty acid that is thought to increase inflammatory markers in the body and contribute to plaque on the arteries, which can lead to heart disease.

Examples of foods rich in omega-6 include:

• Soybean, corn and vegetable oil
• Meat and dairy from non-grass-fed cows

Corn, soybean and vegetable oils are common ingredients in processed foods and commonly used in restaurants, so it's easy to accidentally meet (or exceed) your body's omega-6 requirement without even trying. That's why it's important to read labels and avoid products containing omega-6-rich oils; never cook with corn, soybean or vegetable oils (opt for olive or avocado oil instead); and choose meat and dairy sourced from grass-fed animals (more on that in a minute).

​Get More Omega-3 Fatty Acids​

Omega-3 fats promote anti-inflammatory markers in the body and have been associated with protecting against heart disease, stroke and high blood pressure, according to a January 2014 position paper from the Academy of Nutrition and Dietetics. Basically, the more omega-3 you can get from your diet, the better.

Omega-3s exist in vegan food sources such as nuts and chia, flax and hemp seeds, but this form of omega-3 is less beneficial for the body. The really powerful omega-3s are found in:

• Fish
• Grass-fed meat or dairy
• Seaweed

Keto dieters especially should make sourcing grass-fed meat and dairy a priority. An April 2017 study of conventional versus organic and grass-fed dairy in ​Foods​ showed that organic and grass-fed milk provided a healthier fatty acid profile higher in omega-3 fatty acids.

It may be more expensive, but there are a few tricks to drive down the cost: Consider investing in a deep freezer and purchasing a quarter of a whole cow from your local farmer, or check out wholesale chains like Costco to buy grass-fed meat or dairy in bulk.

Saturated fat, found in fatty cuts of meat, coconut oil, palm oil, eggs and milk fat, was once thought to be harmful due to its supposed effects on cholesterol. But an April 2016 review in the ​British Medical Journal​ concluded that while saturated fat may increase total cholesterol, it does not affect the risk of developing coronary heart disease. In fact, a small randomized trial of 54 participants published in an October 2017 issue of ​Elsevier​ showed that replacing saturated fat with carbohydrates actually harmed participants' good cholesterol markers.

While saturated fat does not have harmful effects, its potential health benefits pale in comparison to those of omega-3 and monounsaturated fats. Saturated fat should not be avoided on a ketogenic diet, but it should not replace omega-3 or monounsaturated fats.

Trans fats are manmade fats that have no redeeming nutritional qualities. The U.S. Food and Drug Administration has banned them for the most part, but they still exist in some foods, including:

• Margarine
• Some fried and ultra-processed foods

You know all the bacteria in your colon so fondly named the "microbiome?" Well, it turns out your microbiome may not like high-fat meals as much as you do.

According to a 2019 article in ​Nature Communications​, eating a high-fat diet may hinder your microbiome's ability to protect the body from absorbing toxins. Those toxins, in turn, may contribute to inflammation in the body.

While the above theory holds true in mouse studies, it is unclear if the same would hold true in humans. In the meantime, a good way to improve your microbiome's health and diversity is to include low-carbohydrate, fiber-rich, non-starchy vegetables in your keto diet. By doing so, you feed the healthy bacteria in your gut while keeping your carbohydrate intake low. Some perfect low-carb vegetables include:

• Kale
• Spinach
• Celery
• Cauliflower
• Brussels sprouts
• Cabbage

So…sauteed kale in avocado oil, anyone?

​Avocado Egg Cups​

2 free-range eggs
1 avocado

1. Slice the avocado in half, remove the seed and carve out a little extra room (enough to fit an egg).
2. Crack an egg in each avocado.
3. Bake for 10-15 minutes at 350 degrees or to desired doneness.

Handful of macadamia nuts

​Tuna and Bacon Salad​

1/2 can tuna in olive oil
1 slice humanely raised bacon, cooked and chopped roughly
1/2 tomato, diced
1/4 cup olives
Lemon juice to taste
2 cups kale, chopped
1 teaspoon fresh parsley leaves, chopped

1. Combine in a large bowl and enjoy as a salad.

​Grilled Portobello Cheeseburger​

2 large portobello mushroom caps
6 oz grass-fed ground beef
1 slice grass-fed cheese of choice
1 tablespoon avocado oil
Salt and pepper

1. Brush the mushrooms with oil and sprinkle with salt and pepper.
2. Salt the meat and form into a patty.
3. Heat a grill or cast iron pan over medium-high heat.
4. Grill portobello mushrooms until soft, about 8 minutes. Remove from heat and set aside.
5. Cook the burger patty for about 4 minutes per side to achieve a medium-doneness.
6. Serve topped with cheese and sandwiched between the mushrooms.