Vegan Keto: Why a Plant-Based Keto Diet Isn’t Good for You

Keto diets have gained popularity for their high-fat approach, and new variations are emerging as people explore different ways to follow them. One trend is the vegan keto diet, which focuses on plant-based foods, high fat and minimal carbs.

A vegan keto diet can support some aspects of performance, offering more fat than a low-fat vegan diet. However, cutting out animal fat and protein creates challenges that make this diet harder to follow. While a keto vegetarian diet may provide more flexibility, fully committing to a vegan keto lifestyle can limit essential nutrients and require careful planning.

This article explores the risks and challenges of the vegan keto diet, what to watch for and how to make the most of this plant-based approach if you decide to try it. Understanding the challenges of a vegan keto diet begins with examining the fats it provides—and the ones it lacks.

A Vegan Keto Diet Makes It Hard to Get Good Fats

Omega-3s

One major challenge with vegan diets is the limited availability of optimal fats, especially omega-3s. While nuts and seeds are common vegan sources of omega-3s, they contain ALA, a form that humans can’t efficiently use. Your body converts only about 6-8% of ALA into the more beneficial EPA and DHA omega-3s, which are crucial for brain, heart and overall health.^[1]

Omega-3 benefits, often tied to EPA and DHA, come from wild fish and grass-fed meat. Without these animal-based sources, vegans following a keto diet may face deficiencies in these essential fatty acids.

Research on omega-3 intake and blood markers in vegetarians and vegans remains sparse, with inconsistent results across studies.^[2] Plant-based omega-3 sources like flaxseed oil show limited efficacy in raising EPA and DHA levels and conversion rates of ALA (found in plants) to EPA and DHA are low. Plus, plant-based diets high in omega-6s may counteract the effects of omega-3s.^[3]

What about omega-6s?

Omega-6s

Omega-6 fats play a key role in brain function, muscle growth and hormone production. However, their link to inflammation is complex. Omega-6 fats, like arachidonic acid (ARA), can produce compounds that influence inflammation. Surprisingly, studies show that eating more ARA or linoleic acid (LA) doesn’t always increase inflammation in healthy people. In fact, higher intake of these fats may even lower certain inflammation markers in some cases.^[4]

However, excessive consumption of omega-6 fats—common in Western diets—can contribute to chronic health conditions.^[5] For vegans, balancing omega-6 and omega-3 intake is particularly challenging because plant-based diets often rely on omega-6-rich foods like nuts, seeds and vegetable oils.^[6] To optimize the ratio, vegans can incorporate microalgal oil, a direct source of DHA and EPA,^[7] while moderating high-omega-6 foods.

On a vegan keto diet, 60-75% of daily calories should come from fat to maintain ketosis and support energy needs. High-quality fat sources include avocados, nuts, seeds, olive oil and coconut-based products like MCT oil, which provides easily absorbed fats that promote ketone production. Pairing these fats with moderate protein intake (15-20% of calories) and minimal carbohydrates (5-10%) ensures a nutrient-dense approach to achieving and sustaining ketosis.

To meet these fat-focused macronutrient goals, careful planning is key—but fat isn’t the only challenge. Getting enough high-quality protein on a vegan keto diet can be just as difficult.

A Vegan Keto Diet Makes It Hard to Get Protein Too

Getting enough protein on a vegan keto diet is tough. Proteins are made of amino acids, and a complete protein has all nine essential amino acids your body needs from food.^[8] On a regular vegan diet, you can combine grains and legumes, like rice and beans, to create complete proteins. Some plant foods, like quinoa and soy, are already complete proteins.

On a vegan keto diet, these options are too high in carbs. Even lower-carb options like tofu can make it hard to stay under your carb limit while still eating enough protein and vegetables to support ketosis. Drinking several vegan protein shakes each day might help, but it’s not a realistic or satisfying way to eat.

Your body needs complete protein to support almost every system. Without enough amino acids, you might notice some adverse issues linked to:

Mood Regulation

Your body needs tryptophan (an essential amino acid) to make serotonin, the chemical that supports mood. Without tryptophan, mood changes can happen quickly but improve once you get enough of it again.^[9]

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Chronic Issues

A lack of amino acids can make you more vulnerable to long-term health problems, including those affecting the brain.^[10]

Immune Health

Your immune system depends on essential amino acids. Without them, your body struggles to fight off infections and illnesses.^[11]

Hair and Skin Health

Proteins keep your hair and skin strong. A shortage of amino acids can cause thinning hair, hair loss, and weaker skin due to reduced collagen and elastin production.^[12]

Your body needs high-quality protein to function properly, but getting enough can already be a challenge on a typical vegan diet. A vegan keto diet makes this even harder, often to the point of being impractical for most people. For those committed to a low-carb lifestyle, vegetarian keto offers a more realistic alternative, as it includes additional protein sources like eggs and dairy while still supporting ketosis.

Vegetarian Keto Supports Plant-Based Keto Goals More Easily Than Vegan Keto

If you want to try plant-based keto but don’t eat meat, a vegetarian keto diet can make it easier to meet your nutritional needs while staying in ketosis. Here are just some of the foods allowed on a vegetarian keto diet:

• Pastured eggs for protein, fat, and dense nutrition
• Grass-fed butter and fish oil for omega-3s
• Bulletproof Coffee for energy and calories
• Brain Octane Oil (supercharged MCT oil) for mental clarity

While high-quality meat and fish can support peak performance, incorporating non-meat animal foods like eggs and butter gives you the tools to succeed on a vegetarian keto diet. With a little planning, you can overcome common challenges and feel great while staying plant-focused.

For a complete list of supplements and foods to support your vegetarian keto journey, check out this guide to going Bulletproof for vegetarians.

Final Thoughts

The vegan keto diet presents unique challenges, from maintaining a proper omega-6 to omega-3 balance to sourcing enough complete protein while staying in ketosis. These limitations make it difficult to meet your nutritional needs without significant supplementation and meticulous planning. However, with thoughtful adjustments and options like microalgal oil for omega-3s or creative vegan keto recipes, you can find ways to navigate these obstacles. Still, the restrictive nature of this diet means it may not be sustainable or realistic for everyone. If you’re thinking of doing plant-based keto, consider trying vegetarian keto first to see if it works with your lifestyle.