Good Fat and Bad Fat in a Ketogenic Diet

Good Fat and Bad Fat

Eating plenty of good fat and decreasing bad fat is a cornerstone concept in a ketogenic diet.  Good fats are necessary for good health and hormone balance.

The fat molecule cholesterol is the base molecule for sooooo many hormones including estrogen, progesterone, and testosterone.

The trend over the last 30 years to go to a low-fat diet has been horribly detrimental to our hormone balance and overall health.

Historically, we have called any unsaturated fat (anything liquid at room temperature) a good fat, and any saturated fat (anything solid at room temperature) a bad fat.  It turns out we’ve been looking at the wrong thing.

So, which are good and which are bad?

Omega-3 Fatty Acids vs. Omega-6 Fatty Acids

The real “good” and “bad” fats have more to do with their fatty acid make-up, rather than whether or not the fat is saturated or unsaturated.

We tend to think of omega-3’s as good and omega-6’s as bad.  This is because omega-3’s are associated with activating anti-inflammatory pathways in the body, while omega-6’s can activate inflammatory pathways.

They are both necessary for good health, and, sometimes, some omega-6’s can act in anti-inflammatory pathways.  It’s the ratio that’s important.

At the turn of the 20th century, the omega-6 to omega-3 ratio was about 1:1.  Today it’s as high as 50:1!  That is, 50 times MORE consumption of omega-6 FA than omega-3 FA.  It’s this ratio that causes inflammatory metabolic pathways to be active in the body.

There are both plant and animal sources of omega-3 fatty acids (FA) and omega-6 FA and we need BOTH to be our healthiest.

Let’s take a quick look at why we want to decrease inflammation, and then talk about good and bad fat.

Why Inflammation Matters

If you’re having an acute injury, you want those inflammatory pathways to be activated because they bring blood circulation and immune system cells to the injured area to aid in healing.

But there are some inflammatory causes that are not acute.  When inflammation becomes chronic, it can cause other more serious problems.  Those things would include increased risk for Alzheimer’s and other dementias, cardiovascular disease, auto-immune diseases, asthma, arthritis, anxiety, depression, and more.

One Contributor to Inflammation

Inflammation is an underlying issue in all of those diseases, but there are a few causes of chronic inflammation in the human body.  Omega-6: omega-3 ratio is one.  In order to decreasing our risk of disease, we must address all areas of inflammation.  In this case, we need to correct that ratio.

Let’s look at both animal and plant sources of omega-3’s and omega-6’s.

Bad Plant Fats


Not all plant oils are healthy.  Sunflower oil, safflower oil, soy oil, corn oil, and cotton seed oil have large quantities of omega-6’s without enough omega-3 to balance them out.

In addition, some of these oils are extracted through a process that requires the use of solvents like hexane.  These oils should be avoided, but they are hidden everywhere.  These are the oils that allow foods to be shelf stable for long periods of time.  They are used to make crackers, cookies, breads, and other processed foods that sit in warehouses, delivery trucks, and grocery store shelves for many weeks or months without going rancid.

You get a double whammy with those foods: they increase insulin because they are grain-based (causing fat storage), and they contain the worst oils for your health contributing to an unbalanced omega-3 : omega-6 ratio.

Let’s look at Canola oil.  While its omega-6: omega-3 ratio is only 2:1, it is extracted using hexane which becomes part of the final product.

In addition, most of the canola, corn, and soy crops in the United States are genetically modified to withstand applications of herbicide which also become part of the final product.

The more processed a food is, the more likely it is to contain these types of oils that cause inflammation and disease.  Be a label reader.  If it’s in a box, bag, or package, read the ingredient list before you buy!

Good Plant Fat


The omega-3 in plant sources is alpha-linolenic acid (ALA).  ALA is not as potent as the animal sources EPA and DHA, but it does have its own anti-inflammatory and other positive effects on the body.  All 3 are necessary.

Alpha-linolenic Acid (ALA)

ALA can be a precursor to the more potent omega-3’s, DHA and EPA.  Studies have shown that not everyone can efficiently convert ALA to DHA and EPA.  Gender, age, other lifestyle issues like smoking will all affect the conversion rate.

Omega-6 fatty acids compete with the enzymes that do those conversions.  If there is too much omega-6’s around, ALA will not be converted to DHA and EPA as efficiently.  Instead, those enzymes will make more inflammatory omega-6’s metabolites.  Balance is the key.

Plant Sources of Omega-3


Nuts and Seeds
Plant Sources Omega-3 (g) per Tablespoonful Omega-6: Omega-3 Ratio
                English Walnuts 2.574g/ 1 tablespoonful 4:1
                Flax Seed 2.350g/ 1 tablespoonful 1:4
                Chia Seed 2.16g/ 1 tablespoonful 1:3
                Hemp Seed 1.0g/ 1 tablespoonful 4:1


The table shows some of the highest sources of plant omega-3’s.  In the second column, we see that English Walnut has more omega-3 than all the other foods, but in column 3, we see that it has much more omega-6’s than omega-3’s.   We see the same ratio for hemp seeds.

The 4:1 ratio isn’t horrible, it’s just not as good as the ratio for flax or chia.  Foods with that ratio are a good source of omega-3’s, but don’t over-do it.  Make sure you always balance your daily intact with a source of omega-3.


Dark, leafy greens have healthy ratios of omega-6 :omega-3 fatty acids although they would not be considered the main source of fatty acids in the diet.

Marine Algae

Not technically a plant, marine algae gives vegans and vegetarians the only non-animal source of DHA/EPA.  Marine algae are a group of many thousands of organisms that include seaweeds and chlorella.  DHA and EPA are made in the leaves of the algae.  Lower marine animals like krill accumulate their omega-3’s by consuming algae, and people can do the same.

Olive Oil

Olive oil has a not-so-great Omega-6 : Omega-3 ratio (13:1), but if used correctly it is one of the healthiest oils we can consume.

This healthy oil has other fat-based molecules that are high in anti-inflammatory properties.  Oleic acid, for example, has been linked to improved heart health, brain health, and breast tissue health, immune system health, weight loss, and many more areas.

Olive oil is high in anti-oxidants, minerals, and fat soluble vitamins.

Observing the smoking point of oil has been the standard of deciding if an oil should be used for cooking and baking.  The smoke point of any oil is the degree at which the oil begins to smoke when heated in a pan.  It’s at this point that the oil is close to its flash point–the point where it will combust into flame.  The International Olive Oil Council states that olive oil’s smoke point is 410 degrees F.

It is commonly thought that heating to the smoking point will hydrogenate the oil.  The process of creating a hydrogenated oil (like unhealthy margarine) does require heat, but also requires hydrogen gas to be added to the heated oil to force hydrogen to be added to the unsaturated fat.  A heating only process will cause a small amount of hydrogenation, but not a lot.

Still, the best way to use olive oil is cold on salads and other foods that don’t need to be heated too much.  Only buy cold-pressed oil so that you know is wasn’t chemically extracted, and balance out omega-6’s with sources of omega-3’s from both plant and animal sources.

Good Omega-6’s

Borage oil, evening primrose oil, and black current seed oil have an omega-6 called gamma-linoleic acid (GLA).  GLA has the potential to go down 2 different metabolic pathways.  In one pathway, GLA is converted to PGE1, an anti-inflammatory prostaglandin.  In the second pathway, GLA is eventually converted into arachidonic acid (AA) which is then converted to several pro-inflammatory molecules.  Trying to push the reaction to follow the first pathway rather than the second is the goal.  One way to do this, is to take more omega-3’s which will compete with the enzyme that takes omega-6’s down the arachidonic acid pathway.

When choosing one of the above oils for supplementation, make sure it is cold or expeller pressed.

Vegan/Vegetarian Source Supplements

Vegans and vegetarians are often unaware that their healthy diet choices are offset by this omega-6: omega-3 ratio.  Too many have high inflammatory markers that in part can be brought down by supplementing.

  1. Flax seed.  For proper flax seed preparation and use, see the article “Flax Seed for Health”.
  2. Algal oil supplements, such as this one from Nested Naturals can supply the vegan/vegetarian diet with much needed DHA and EPA. Look for supplements that don’t have a lot of inactive ingredients such as carrageenan, corn starch, and sunflower oil.  Research has shown that circulating blood levels of DHA significantly improve with algal oil supplementation.


Animal Omega’s

The animal omega-3’s include docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA).  These fatty acids are necessary for brain health, gut health, cardiovascular health, immunity and more.  DHA and EPA are more potent than the ALA that is available from plants.

Fatty fish are the richest animal sources of omega-3 fatty acids.  Farm raised fish have been found to have high levels of toxins, synthetic vitamins, antibiotics, and much more.  When you eat fish, eat wild caught.

Fish Mg of Omega-3 per Ounce
Wild Herring >500mg
Wild Mackerel >750mg
Wild Salmon >400mg
Blue Fin Tuna 300-500mg
Tuna 250-300mg
Sardines 250-300mg
Oysters 250-300mg
Muscles 250-300mg


Other animal products (meat, milk, and eggs) contain varying omega-6: omega-3’s ratios depending on how the animals were raised.

Cows, for example, raised on grains, which contain large amounts of omega-6 fatty acids, will have meat that contain a ratio of omega-6: omega-3 as high as 20:1.  Corn is given to cows to fatten them up and genetically modified soy is a cheap source of protein. The end-product is unhealthy meat and dairy from unhealthy animals.

Cows are not designed to eat grain.  They are designed to eat grass.  Pastured cattle have an Omega-6: Omega-3 ratio closer to 1:1. Animals are healthy when they are raised in a way that honors their design.  Anything else will make them sick.  Just like people.

The same goes for pastured pork, chicken meat, and eggs.

So, while you want to keep your protein intake low to moderate, depending on activity level (see post here for more on that), when you eat animal products, choose pastured sources.  Good animal fats come from pastured animals, bad fats come from animals raised in crowded closed conditions that are fed diets high in omega-6 containing feeds.

Animal Source Supplements

Whole Fish oil

1000mg capsules.  Take 2 to 4 daily.

Look for oils that don’t have citrus added to them, which may be a way to disguise rancid odor or flavor and, like algal oil, choose one that doesn’t have a lot of inactive ingredients as additives.  I’ve been using this one from Carlson, but I like this one from Dr. Tobias, also.

Krill Oil

Krill oil is the highest potency and purest way to get animal sources of omega’s.  Since krill are at the bottom of the animal food chain, it doesn’t have the heavy metal contamination that fish oil can have.  Krill oil also has phospholipids which aid in absorption and astaxanthin which is a potent antioxidant.  Again, look for low-ingredient additives like this one from Viva Naturals.


Decreasing the inflammatory response due to the omega-6: omega-3 ratio should be attacked from two fronts:

  1. Decreasing omega-6 intake
  2. Increasing omega-3 intake

It’s a simple strategy that fits in with eating a plant-based ketogenic diet.  Most omega-6 consumption comes from factory farmed animals and pre-made, baked, highly processed foods that sit on a grocery store shelf for ages.

This week take out some of those processed foods, and replace them with some fresh vegetables and fish.  You’ll be glad you did!

A Call To Action!!

If you’re ready to get started on the healthy way to do keto but need all the information organized into one document, you can get The 30-Day Whole Food Keto Challenge digital PDF for $20.  Here’s what you get:

  • The nuts and bolts of how to get into Ketosis
  • How to track your nutrient intake
  • How monitor ketone bodies for successful weight loss and maximum anti-inflammatory action on your body
  • support
  • Daily guide and weekly “What to Expect”
  • Dealing with so-called “keto side effects”
  • Shopping lists
  • Tips and tricks
  • Unlimited email communication to give you support for your personal situation
  • Membership for women in our private Facebook group for weight loss and hormone balance: Healthy Living
  • and much more…

I’ll help you every step of the way.

Further Reading on a Ketogenic Diet

For an overview of how a ketogenic diet causes fat loss please read “Keto Diets:  Healthy or Harmful?“, and for a discussion on the other macronutrients please see the articles “Good Carb, Bad Carb” and this on”Good Protein, Bad Protein”.

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