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Can a vegan keto diet work?

Last updated: Oct 24, 2020 at 9:25AM | - Published on: Oct 14, 2018

Written by Sarah Neidler, PhD

Scientifically Reviewed by Raphael Sirtoli, MSc

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A keto diet and a vegan diet, aren’t they the exact opposite? Is it possible to combine the two? The problem is that most people have misconceptions and stereotypes in their head that are not necessarily true. Let me give you an example.

Recently, a friend of mine got to know that I follow a low-carb diet. I did not even mention keto. Considering that this friend is vegan that would seem like a crazy diet to adopt. I like harmony in my life and try to avoid emotionally loaded discussions about diet. My first mistake in this conversation was answering “I’m just trying to be healthier…” when asked why I follow this diet. How can the Atkins diet, replete with meat, be healthy? Didn’t die Dr.Atkins from eating his diet? (no, he died from head trauma).

Wait, who said that I’m on an “Atkins” diet? Didn’t I say low-carb, while meaning keto? This is exactly what I mean with stereotypes. When someone hears low-carb, they may think “few veggies, little fiber, poor digestive health”. On the other hand, when someone hears vegan, they think “greens and other colorful vegetables”. In truth, the low-carb diet could have tons of low-starch high-fiber vegetables, or it could be an all-meat diet. The vegan diet could be full of white bread, soda, and seed oils, or it could be rendered less harmful by prioritizing higher-protein plants like legumes and fats from avocado or olive oil (and even some bivalve sea creatures!). Yes, it’s true that both diets are quite restrictive, but they both offer a variety of different foods

By paying attention to the principles behind both diets instead of the stereotypes, you can construct a vegan ketogenic diet (a ketogenic diet absent animal foods). You will still need to supplement with complete sources of protein, B12, possibly with DHA/EPA or eat lots of bivalve sea creatures (since many don’t really see them as sentient creatures). Since I follow a ketogenic diet, I eat more vegetables than before, and this is quite a common report. Before looking at what a vegan and a keto diet have in common and how to possibly combine the two, let’s clarify how the two diets are defined.

What’s a keto diet?

A ketogenic diet is by definition high in fat, low in carbs and adequate in protein. Ideally, less than 5-10% of calories should come from carbs, 70-90% from fat and 20-30% from protein. The diet is called ketogenic because your body will produce ketones when following this diet. Ketones are a very good source of energy and you can easily measure if you are in ketosis.

A keto diet is a high fat low carb diet with a minimum of 70% of your daily calorie intake from fats, 25% from proteins and 5% from carbs.

This distribution of macronutrients eliminates anything that is very high in carbs such as grains, sweets, and lots of fruit with high sugar content like grapes or bananas. Also, legumes, which can have a good whack of carbs, should be avoided or strongly moderated. Leafy greens like kale and other low-starch plants can be consumed liberally.

Vegetables with a low to moderate starch content such as red peppers and carrots, and fruits with a relatively low sugar content such as berries, can be eaten but in small amounts as long as they fall within your daily carb tolerance. Vegetables or mushrooms should be cooked with butter, ghee or coconut oil, not only for taste better but because they’re harder to oxidize and help you absorb certain micronutrients from plants and animals (the fat-soluble ones).

Meat and fish can be eaten without restriction, but you should try to get hold of the fatty pieces such as mackerel, herring, salmon,  and anchovies. They’re ideal to help you meet your daily calorie and micronutrient requirements. People on ketogenic diets tend to favor fatty meats as they tend to be tastier, more filling and quite nutrient dense. Lean cuts are fine as long as they don’t cause you to go to low calorie or suppress appetite counter-productively for instance.

The ratio between vegetables and meat is really up to you. Traditionally, a ketogenic diet contains more meat than high-carb diets. But as long as you make sure not to eat too many carbs by choosing low-carb vegetables, you can eat plenty!

Nuts are also an excellent fat source in a keto diet. Macadamia nuts and pecan nuts are ideal because they have a very high fat and a very low carb content. Also, coconut is your friend: you can eat it raw or use the milk, an all-rounder in many keto dishes.

Eggs arguably deliver the highest-quality protein, as well as excellent sources of fat and phospholipids. They can be eaten fried, poached, boiled or scrambled and are also an essential part of many keto dishes.

A keto diet may or may not contain milk products. Milk itself has quite a lot of carbs and should be consumed in moderation. A sip of milk in your morning coffee is fine, but if you drink a whole glass of milk, you probably already consumed half the amount of your daily carb allowance. Cheese, however, contains almost no carbs (especially the hard ones that fermented the lactose away, like Parmesan), and is an excellent source of high-quality protein and fat.

Did you know?

that the modern ketogenic diet can be seen as an improved version of the popular clinical ketogenic diet first used to treat epileptic kids? These 90% fat diets were effective, even more effective than medications for those drug-resistant kids.

However they were high in seed oils and inadequate in protein, both in terms of quantity and quality. This level of fat is unpalatable and unnecessary for the vast majority of people without serious medical conditions trying a ketogenic diet.

Protein, especially from animal foods like red meat, has been feared in recent history for reasons that turned out to be false (like the association with colon cancer). Now a new fear, that of decreased ketogenesis, has surfaced. It’s misguided and stems from the simplistic and false belief that ‘the more ketones the better’.

What’s a vegan diet?

The definition of a vegan diet is to eat no animal products, a precept coming from religious views based on puritanism. This excludes meat, fish, eggs, milk products, and even honey depending on who you ask!

Instead, you can eat all kind of vegetables, legumes, mushrooms, fruits, nuts, and seeds on a vegan diet. Technically, a mushroom is an ‘animal’ at the cellular level, but we’ll let that slide…A vegan diet does not have any rules about carb or fat content, so yes, a vegan diet that is low in carbs and high in fat (or ketogenic) is possible by definition!

What’s a vegan keto diet?

Is it possible to live on a keto diet without meat, eggs and milk products? You simply watch the carb intake, and you have a keto vegan diet. Is it that easy?

Well, yes and no. You remember that the main source of energy is fat in a keto diet? Is it possible to get enough fat on a vegan diet? Because you eat so much fat on a keto diet, it is especially important that the fat you consume is of high quality.

You certainly want to avoid oxidized seed oils if you don’t want to threaten your health. So what are the healthy vegan fat choices? There are plenty: avocados, coconuts and some other nuts are excellent fat sources that are also low in carbs. For cooking, coconut oil is ideal, and avocado oil, olive oil, and MCT oil can be used for cold dishes, such as salad.

So, all set. Low carb vegetables, mushrooms, and nuts in combination with vegan oils and we have a low-carb high-fat vegan diet. Or did we miss anything? What was the third macronutrient again, and isn’t it essential?

The protein problem

Correct, we all have to eat protein. On a keto diet, it is consumed in moderation but no matter what kind of diet you follow, everybody needs it. The proteins’ building blocks are amino acids, which we need to build our own proteins demanded by our body. There are 20 different amino acids, 9 of them are essential, which means that we cannot make them ourselves and we have to get them from external sources. The other 11 amino acids we can build ourselves.

There are some we call conditionally essential, meaning that in some instances you can’t produce all that you need and have to get some of those amino acids from your diet.

So where is the protein in our vegan keto diet that we just assembled and is it enough? We need at least 0.8 g protein per Kg of body weight per day to avoid outright deficiencies and at least twice as much to get closer to optimal. So for an 80 Kg man, that would be 64 g protein.

Remember, 3 g of protein from refined flour is far less bioavailable than 3 g of protein from a poached egg…this is more or less true when comparing protein availability from plants vs animals across the board. Let’s take a look at the protein content (per 100 g) of the foods on our theoretical keto vegan diet.

  •    Low carb vegetables: kale ~3 g, spinach ~ 3g, zucchini ~ 1g, cauliflower ~ 2g, broccoli ~ 2g
  •    Nuts: macadamia nuts ~ 8g, pecan nuts ~ 9g, walnuts ~14g, hazelnuts ~15g
  •    Mushrooms: white mushrooms ~2g, oyster mushrooms ~3g, chanterelles 1.5 g, shiitake mushrooms ~ 2g
  •    Berries: strawberries (actually a nut) < 1g, raspberries ~ 1g, blueberries < 1g, blackberries ~ 1g

Here you will find the full vegan keto food list.

From this list, you probably agree that it will be difficult to get enough protein. You would have to eat at least 2,000 g of vegetables and/or mushrooms per day. Some nuts have quite a lot of protein, but most people don’t eat more than 100 g per day.

So what’s the usual source of protein for a vegan? Legumes such as lentils, peas, chickpeas, and beans are a good source of protein. Lentils have ~25 g, chickpeas ~20  g, green peas ~5 g, and kidney beans ~ 20 g.

Can we eat legumes on a keto vegan diet? The problem is that they all have a lot of carbs, some of them even about 50 g per 100 g. So if you decide to eat legumes, most if not all of your carb allowance should be spent on legumes and other such higher protein foods to help you get as much protein as you can before being kicked out of ketosis. It’s not easy! Small amounts of legumes won’t be enough to cover your daily requirement of protein.

Luckily, there is a second path for getting more protein in on a vegan diet. There are quite a few products made from soybeans that have a high protein content but are low in carbs. Tofu, Tempeh and soy yogurt are popular examples. The exact nutrient content varies from manufacturer to manufacturer, but Tofu and Tempeh contain up to 20 g protein per 100 g and usually less than 1 g net carbs.

Anything else? Well, there are quite a lot of vegan protein products. With vegan protein powders, you may be able to supplement away the worst of amino acid deficiencies. Another problem with protein from plant sources is that it is not of high quality. That means that the distribution of the protein building blocks, the amino acids, is not ideal. Even if you eat enough protein in theory, you may not get the right balance of essential amino acids.

Without supplementation, you’ll be far from optimal if not deficient over the long-term in the amino acids

  • Taurine
  • Methionine
  • Glycine

A well-formulated keto vegan diet with Nutrita

Yes, a keto vegan diet is possible! We don’t recommend it, but it can be done as long as you carefully supplement certain nutrients and make very wise food choices. It should be based on low-carb vegetables that offer a huge variety of vitamins and other micronutrients, nuts that deliver healthy fats and no vegetable oils. Preferably, and this is key, it should include eggs, dairy and bivalve crustaceans

There are, however, quite a few things that you have to avoid, because both the keto and vegan diets exclude specific groups of food. Nutrita makes sure you stay ketogenic by providing you with an insulin index and keto score of foods.

It also gives you a dynamic nutrient density score so that you get enough vitamins, protein, minerals and other micronutrients, which is otherwise a bit tricky on this diet.

Nutrita considers not only the nutrient content of food but also its bioavailability. Bioavailability determines how much of a specific nutrient, like calcium for example, you will be able to absorb. This is especially important when it comes to protein needs on a vegan diet which is at an inherent disadvantage given the highest quality protein is found in animal flesh.

Plant proteins are not only lower in quality, meaning that they don’t all the essential amino acids in the right amounts, but they’re also less bioavailable. Nutrita tells you how much protein from a specific food your body can absorb so that you can avoid complicated calculations and can simply enjoy your healthy meal!


There are some vitamins and minerals that you hardly find in plants. So if you avoid animal products, you should consider supplementing them.

The list of supplements you should take on a vegan keto diet.

Vitamin B12: You find vitamin B12 only in animal foods in noteworthy amounts. If you don’t eat animal products at all, you have to supplement it.

Vitamin B6: Fish is the primary source for this vitamin. In non-animal foods, nuts and seeds are the best sources. Some of them have about 1 mg per 100 g. Also, herbs contain considerable amounts of this vitamin, but most people use only small amounts of herbs for seasoning. Considering that you need about 2 mg vitamin B6, you should supplement it.

Vitamin D3: It is also called the sunshine vitamin. The only food source with considerable amounts of this vitamin is fatty fish. Avocados and some mushrooms also contain some vitamin D3. If you spend most of your time inside and don’t eat multiple avocados per day, you should probably supplement it during winter.

Omega-3 fatty acids DHA and EPA: Fish is rich in these essential omega-3 fatty acids. If you don’t eat fish, you should consider supplementing it.

Iron: The ‘better’ version of iron is heme iron and is only found in animal foods. Soy products and seeds contain decent amounts of iron but the less absorbable kinds called non-heme iron. It’s a losing strategy to try to cover your protein requirements with soy products, so go for a high-quality iron supplement instead.

Calcium: Many vegan foods contain decent amounts of this mineral: most nuts and leafy greens have at least 100 mg per 100 g. But considering that we need 1,000 mg per day, some will choose to supplement it if not consuming dairy products. Nevertheless, calcium supplementation is not a risk-free intervention so consult a knowledgeable nutrition or doctor to figure out if it’s worth it.

Magnesium: Most people don’t get enough magnesium, no matter what diet they follow. Supplementing this mineral is a good idea for everyone and unlikely to cause harm. Make sure you get the more absorbable version like Magnesium citrate or Magnesium chloride.


At first, a vegan diet seems to make complete sense for many people from the animal welfare point of view. This is in fact being challenged by more and more people who are coming to understand the devastation caused by monocrop agricultural practices.

Animals are exploited for milk production as much as they are for meat production, maybe even more so. Yes, it is possible to avoid outright protein deficiency (kwashiorkor) on a vegan or even on a keto vegan diet, but in the end the overall protein quality is much lower than from animal sources.

We strongly recommend you at least consider eating either eggs, dairy or bivalve crustaceans.

Yes, large-scale poultry operations are mostly terrible. But there are decent farms out there that take animal well-being seriously – so vote with your dollars! Maybe you can find one in your area and even visit to see how poultries are treated and kept. Eggs are a real superfood.

They contain protein of the highest quality, healthy fats, all B vitamins and all other vitamins besides vitamin C. You wouldn’t have to worry about protein, and it would be an immense upgrade from soy products.

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Written by Sarah Neidler, PhD

Sarah Neidler did her PhD in cancer research at the Beatson Institute for Cancer Research in Glasgow. She has a strong interest in nutrition and the ketogenic diet and believes that they are beneficial for the treatment and prevention of chronic conditions, such as heart disease and diabetes. She loves cooking, reading, sewing, Yoga, and CrossFit.