Keto vs Vegan: Which Is Better? (Benefits and Risks Compared)

Keto and vegan are very different approaches to food. And yet, they’re both soaring in popularity at the same time. When so many sources seem biased or one-sided in their conclusions, how do you know who to trust?

After spending weeks researching and writing this post, here’s my conclusion: Keto wins when it comes to quick weight loss—but vegan wins on almost everything else (and especially heart health).

Below, I’ll be comparing keto vs vegan on these issues:

I’ll also discuss the vegan keto diet (yes, you can combine them!) and whether you should be considering that!

Keto vs Vegan: Pros and Cons

One of the fatty plant foods that vegans and keto dieters can agree on: Almonds!

Let’s start with a bird’s eye view on the keto vs vegan debate. I’ll provide sources for all these conclusions below, but here’s an overview:

  • Both diets can work for weight loss.
  • Keto weight loss tends to be a bit faster, but vegan weight loss tends to be longer-lasting.
  • Most authorities (but not all) say a vegan diet is much healthier overall—as long as it’s focused on whole foods.
  • Vegan is the winner for heart health, and it seems to be winning for cancer prevention and longevity, too.
  • When it comes to diabetes, there’s a lot of controversy and debate between these diets!
  • Both diets are quite restrictive, so they both come with risks.
  • Both diets can impact blood sugar, blood pressure, and other factors—so if you take medications, let your physician know!

Disclosure: I’ve been vegan for 12 years. I’ve never been keto. That said, I’ve studied both diets extensively, and I cite many experts in this post. I’m trying to provide a balanced view. But still: You’re getting the perspective of a vegan.

What Is a Keto Diet?

Keto is short for “ketosis,” a state your body enters when it lacks carbohydrates to burn as energy. Your liver creates ketones (or ketone bodies) from fat, to use as an alternative fuel source.

A keto diet is also called a ketogenic diet because it’s a diet designed to put you in ketosis. As such, it is a low-carb, high-fat diet.

The ketogenic diet was historically only used as a therapeutic diet for children with epilepsy. A keto diet can reduce or eliminate seizures in many of these patients by providing ketones as an alternative fuel source for the brain.

In a medical context, a ketogenic diet is monitored closely and strictly. Foods are weighed and ketone levels are tracked to ensure a specific outcome for patients.

Today, the “keto diet” is often practiced more casually for weight loss. As a result, it often looks a lot like the Atkins diet, which is both high-fat and high-protein: Lots of meat, butter, fish, and eggs, with some greens on the side. (Look up “Dirty Keto” to see how far keto today can stray from the actual medical diet.)

Mayo Clinic Radio discusses clinical vs popular ketogenic diets with Katherine Zeratsky, RDN.

What Is a Vegan Diet?

A vegan diet is a type of vegetarianism that excludes all animal-derived ingredients. As such, it is fully plant-based, with no meat, no fish, no dairy, no eggs, and usually no honey or other animal by-products, either (depending on how strictly it is practiced).

Veganism is often motivated by ethical reasons like a belief in animal rights or stopping climate change. See my full blog post on vegan ethics for a guide to common moral arguments made by vegans.

In recent years, a vegan diet is also increasingly common for health reasons. In this case, it is often just called a plant-based diet.

Vegan diets usually focus on grains, beans, vegetables, nuts and seeds, and fruits. Many vegan diets also include some amount of processed foods like Beyond Burgers and even vegan chips and cookies. Some vegans, however, follow a strict “whole-food plant-based diet” with few processed foods.

Vegan diets tend to be moderate- to high-carb diets—but they can be done in low-carb ways, too. I’ve personally been vegan for over 12 years, and my diet has looked very different within that range of time. The only rule is avoiding animal products.

Keto vs Vegan for Weight Loss

Keto and vegan diets have both shown significant weight loss results. The details depend on exactly how you do it—but on average, keto weight loss usually comes a bit faster, while vegan weight loss is usually healthier and easier to sustain. (source)

Appetite Suppression

One of the strong points of the keto diet is that all the dietary fat can keep you satiated, so you eat less overall.

With a healthy vegan diet, you will probably eat a higher volume of food. Your stomach will get filled up with low-calorie foods like veggies and fruit, along with fiber-rich whole grains and beans. That can help you feel more full, too.

In my experience, it is possible on a vegan diet to get hungry again just a few hours after you ate. If you’re experiencing that, try to add more protein and fat to your diet: tofu, tempeh, seitan, nuts, avocado, peanut butter. And check out my other post with 11 tips to stay full on a vegan diet!

When it comes to appetite suppression, keto probably wins overall. But if you’re eating healthy vegan foods, you can potentially eat all day and still lose some weight.

Preserving Lean Mass

What most people want in a diet is not just “weight loss”—you want fat loss. Most dieters want to keep their muscle and maybe even build more of it. So you want a diet that targets fat loss and preserves your lean mass (like muscle).

According to Heathline, keto dieters have been shown to lose more lean mass. However, I’ve heard keto advocates claim that this is a short-term effect and that keto is great for athletic performance in the long term. More on that below.

On a vegan diet, keeping your muscle may require paying extra attention to protein. Ideally, you’ll want to keep your protein intake up around 0.8 grams per pound of bodyweight. And that’s higher than most vegans will naturally eat—so be sure to eat plenty of beans, tofu, seitan, tempeh, or maybe protein powder.

Whichever diet you’re following, you can also preserve muscle by doing resistance exercise: Lift some weights. Then your body will be getting the right signals to know it needs to keep the muscle!

Short-term vs Long-Term Weight Loss

In the U.S. News‘ Best Diet Rankings, keto scores a 3.8 out of 5 when it comes to short-term weight loss, but only a 2.2 for long-term weight loss.

Compare that to the rankings for a vegan diet: 3.6 for short-term weight loss and 3.3 for long-term weight loss. So a vegan diet is almost as good as keto for short-term weight loss, and a full 1.1 points above keto for long-term weight loss. (source)

Overall, both diets can work for weight loss. They both have many success stories you can find and read about. So it’s partly just a matter of which diet you can enjoy and stick to. But overall health is also important for the long term…

Which is Healthier: Keto or Vegan?

Comparing the healthiness of keto vs vegan can be hard because advocates on each side usually only share evidence that supports their side.

As a result, you’re usually getting an incomplete view when you only follow one source. But by seeking out a range of sources, you can get a fuller picture of the debate.

Let’s start with a couple of overall assessments:

  • In the U.S. News‘ Best Diet Rankings in 2020, keto scored only a 1.8 out of 5 for its “Healthy” factor. The vegan diet scored higher, with a 3.2 in that category. (And variants of the vegan diet, like the Ornish Diet, scored as high as a 4.1.) (source)
  • In an article in Women’s Health, Julie Upton, R.D., mentioned that, while keto often results in “faster” weight loss, “vegan is much healthier and can help you reach and sustain a healthy weight.”

And this is the overall feeling I got after reading through dozens of sources for this post: Keto is effective for quick weight loss, but kind of sketchy in other health areas.

Now let’s look at some specific health issues.

Keto vs Vegan for Longevity

Overall, a vegan diet appears to support longevity much better than a keto diet. However, since long-term research on fully vegan populations and fully keto populations is lacking, this conclusion is mostly extrapolated from related studies.

One such study came out in The Lancet in 2018. It was a long-term study on carbohydrate consumption and all-cause mortality. They found:

  1. Lowest mortality was found with moderate carb intake (50-55% of calories). People who ate very high-carb (>70% of calories) and those who ate low-carb (<40% of calories) diets both had more deaths, creating a U-shaped association.
  2. People who ate more plant sources of fat and protein fared better than those eating animal sources. More important than overall macronutrient ratios was having a plant-focused diet.

Here are the implications the researchers drew:

“These data provide further evidence that animal-based low carbohydrate diets, which are more prevalent in North American and European populations, should be discouraged. Alternatively, if restricting carbohydrate intake is a chosen approach for weight loss or cardiometabolic risk reduction, replacement of carbohydrates with predominantly plant-based fats and proteins could be considered as a long-term approach to promote healthy ageing.” (source)

One objection that keto advocates may have to this study is that the “low-carb” group included anyone eating below 40% of calories from carbs. But keto is typically around 5% of calories from carbs—that’s much lower

A diet that is 35% carbs would likely not keep someone in ketosis, so its biochemical impact may be quite different from a true ketogenic diet.

That said, the Lancet study, with its U-shaped association between carbs and mortality, is concerning for many people on animal-based low-carb diets of any kind. It cast a lot of doubt on the long-term impacts of eating keto, which may not be visible based on your short-term results.

Another reason many people doubt the long-term viability of keto is the lack of successful, long-term populations we can study who have eaten anything close to it.

Blue Zones: The Longest-Living Populations on Earth

Part of the reason plant-based diets are thought to be excellent for longevity is due to the diets eaten in so-called “Blue Zones” around the globe.

Blue Zones are populations with particularly high life expectancy, including the Seventh-Day Adventists in California and the Okinawans in Japan.

Sweet potatoes—not eaten on a keto diet—are one of the staple foods eaten by populations with long life spans.

Many of the people in these populations live to over 90 and even 100 years old. And one of the main reasons for their longevity is thought to be diet. (source)

Blue Zones tend to have diets composed of around 95% whole plant foods. Although these populations are not completely vegan, their intake of animal foods is typically quite low. (source)

And their consumption of fat is pretty low, too. It’s not like these populations were eating a plant-rich keto diet—not even close! They’ve focused on healthy carbs like sweet potatoes, barley, corn, and other vegetables and fruits. (source)

Although the low-carb paleo diet is based on an idea of what our ancestors may have eaten before modern agriculture, the data we have on those past populations is quite weak. It certainly doesn’t compare to case studies of recent world populations that we know live long, healthy lives.

Beans: One of the Best Foods for Longevity

In a study that followed five elderly cohorts for seven years, eating legumes was the most important dietary predictor of survival. (source: Asia Pacific Journal of Clinical Nutrition)

In fact, no other food group besides beans was shown to have a statistically significant relationship with mortality.

And that is not the only study showing the life-prolonging effect of beans. This study showed that Taiwanese women eating a bean-free diet died more compared to those eating beans. This study showed that soy food consumption was linked to more survival for breast cancer patients.

Dr. Michael Greger explains the research on beans and longevity.

Since beans are high in carbohydrates and very low in fat, they are not included on a keto diet. Meanwhile, most vegan diets emphasize beans as one of the main replacements for animal protein.

So again, this supports the idea that a vegan diet may be better for longevity than keto on average.

Keto vs Vegan for Cancer

Significant evidence points the fact that a vegan diet reduces cancer risk when it’s centered on whole plant foods. When it comes to keto, there are some studies showing potential anti-cancer benefits, but many of the studies are in mice at this point.

Human colorectal cancer cells.

This Mayo Clinic article on plant-based diets and cancer risk emphasizes that vegans appear to have the lowest cancer risk of any diet group.

The American Institute for Cancer Research (AICR) is more hesitant to tout the benefits of veganism specifically—but they do agree that vegetarian and plant-based diets reduce cancer risk. (source)

The AICR also cites a large U.S. study in which men on a vegan diet had 35% less incidence of prostate cancer. In that study, even other kinds of vegetarians did not experience the same benefit.

A 2015 study in JAMA Internal Medicine found that vegetarian and vegan diets were linked to less colon cancer compared to diets including meat. Since most keto diets include meat, this is arguably another point for the vegans.

It should be noted, however, that the JAMA study also showed great results for pescatarians, who still eat fish. And the nonvegetarians in the study were not on a keto diet specifically.

A 2019 study by the Women’s Health Initiative (WHI) showed better breast cancer outcomes for those following a low-fat diet (only 20% of calories from fat).

On the surface, that suggests a high-fat keto diet may be headed in the wrong direction. But again, the control group was only eating around 35% of calories from fat—nowhere near actual keto.

Research Being Done on Keto and Cancer

There are some studies that show potential for a keto diet helping with cancer—but at this point, the studies are in mice, not humans.

The explanation for keto being anti-cancer is mainly based on the fact that cancer cells feed on sugar—the “Warburg Effect.” So, if you cut way back on the amount of sugar in your body, maybe it could reduce the rate of cancer growth.

But the human body is complicated, and we need real human studies.

Dr. Siddhartha Mukherjee has done some research which actually suggests that a keto diet can accelerate certain kinds of leukemia. But he also found that a keto diet may be helpful in other kinds of cancers when combined with other treatments. (source, source)

If that’s the case, then more research should be done on keto and cancer—but if you’re a cancer patient, you probably shouldn’t try to DIY it.

To learn more about the research being done on keto and cancer, I recommend this article from cancer research organization Fred Hutch.

Keto vs Vegan for Heart Health

Heart health is another area where the vegan diet stands head and shoulders above the keto diet.

U.S. News ranks the keto diet 31st out of 35 diets for heart health—near the bottom of the list. Meanwhile, they rank the vegan diet 4th out of 35 diets for heart health. (source)

Notably, the Ornish Diet, which is a mostly-vegan diet, is actually ranked #1 for heart health by U.S. News. And that’s for good reason.

The Ornish Diet has actually been shown capable of reversing coronary artery disease by opening up clogged arteries and increasing blood flow to the heart muscle (source). Talk about a heart-healthy diet!

The Baton Rouge Clinic also argues* that a plant-based diet is healthier than a keto diet for heart health. They specifically cite the role of fiber in reducing rates of heart disease, hypertension, and diabetes in vegetarians compared to meat-eaters. (*link removed)

Fiber is only present in plants—not animal foods. While it’s possible to get adequate fiber on a keto diet, it’s easier to get the ideal amounts on a vegan diet including beans and whole grains.

In fact, most vegan diets are so high in fiber that many new vegans have temporary gas issues while adjusting to the diet. See my post about stopping vegan farts for more on that!

Keto and Heart Disease

A keto diet could reduce heart disease risk if it helps you lose weight. Losing weight generally reduces your blood pressure, too, and both of these are heart disease risk factors. But many keto dieters end up regaining the weight—so the benefits don’t last. (source)

In fact, this “yo-yo dieting”—when you lose weight and then gain it back again—has actually been associated with a 40% higher risk of heart attack or stroke (source).

So using diets like keto to repeatedly chase short-term weight loss may be harmful to heart health in the long run.

Another concern for keto dieters is cholesterol levels.

Many keto dieters eat a lot of saturated fat (common in animal products and coconut oil). Saturated fat can raise your LDL (“bad”) cholesterol, which is a risk factor for heart disease (source). Some keto practitioners may dispute this fact, but as of now, it remains the medical consensus.

In contrast, vegans naturally have lower cholesterol levels, along with other heart disease risk factors like blood pressure, body mass index (BMI), and more. (source)

Keto vs Vegan for Diabetes

The keto diet and vegan diet both have success stories when it comes to diabetes, particularly type-2 diabetes. There is some concern, however, that a keto diet may only relieve the symptoms of diabetes, while a plant-based diet has the potential to actually increase your glucose tolerance.

Before we get into the details: If you’re diabetic, you should talk to a physician or registered dietitian before going keto or vegan. Individual factors may need to be considered, and medications may need to be adjusted.

Vegan for Diabetes

A vegan diet can reduce the risk of type-2 diabetes and potentially reverse type-2 diabetes, as well. One reason for this is that vegan diets are naturally low in saturated fat.

Excess saturated fat intake can lead to insulin resistance. A 2001 study in Diabetologia found that replacing monounsaturated fat in the diet with saturated fat led to worsened insulin sensitivity in healthy subjects. Since most saturated fat comes from animal foods, vegans avoid this problem.

Another reason vegans get less type-2 diabetes may just be due to lower body weights. Obesity is known to worsen insulin resistance—and vegans as a group experience less obesity. (source)

Credible sources like WebMD acknowledge that a vegan diet can help you manage blood sugar levels. Everyday Health agrees that a vegan diet can prevent or reverse type-2 diabetes.

To learn about reversing type-2 diabetes with a vegan diet, look into Dr. Neal Barnard’s work. He runs the Physicians Committee for Responsible Medicine, which publishes this resource on diabetes. He also wrote the following books on it:

Keto for Diabetes

A ketogenic diet can help lower hemoglobin A1c in diabetics, and the weight-loss can help type-2 diabetics (source). However, the difficulty of sustaining a keto diet long-term may make it a poor choice for managing a chronic condition.

A 2019 study published in Nutrients, while citing some exceptions, concluded that ketogenic diets can help type-2 diabetics and obese patients, although it’s not the only diet that does so.

Dr. Joseph Galati, a hepatologist in Houston, TX, warns against keto for type-1 diabetics. He says the acidic ketone build-up can be hard on your kidneys. Dr. Galati says type-2 diabetics can tolerate keto but should approach it “with extreme caution.” (source)

But my biggest overall concern about keto for diabetics has to do with possible worsening long-term insulin resistance. So let’s cover that.

Insulin Resistance on Keto

Oddly enough, there may be a risk of developing insulin resistance on a keto diet. Although you’re eating way fewer carbs on keto, all the fat you’re eating may actually cause your body to become less capable of handling the carbs you do eat.

A build-up of “intramyocellular lipids” (fat inside your cells) can potentially cause insulin signaling to stop working effectively. This is insulin resistance and potentially the beginning of type-2 diabetes.

Diabetes educator Drew Harrisburg, formerly a keto dieter with type-1 diabetes, explained how his keto diet started off great, but it went bad after about two months:

“[A]fter two months, everything took a horrible turn for the worse. I became the most insulin resistant I have ever been. I lost all metabolic flexibility. Sure, I was a very efficient fat- and ketone-burner, but it was at the expense of the ability to tolerate any glucose whatsoever. Not only could I no longer eat the smallest amount of carbs without a massive blood sugar spike but also I was resistant to the insulin that was meant to bring my levels back into the normal range.” (source: “Why I Quit the Keto Diet”)

Granted, Drew is not the average keto dieter, as he started as a type-1 diabetic. But he’s not the only one who emphasizes how a high-fat diet can mess with insulin signaling.

The following video does a good job explaining how, despite keto’s beneficial short-term impact on blood-sugar levels, it can actually make you less capable of tolerating carbs over time.

Dr. Michael Greger explains why keto dieters may experience worsening glucose tolerance.

So, similar to how weight-loss results on keto are often just short term, the benefits to blood-sugar and hemoglobin A1c may also be short-sighted.

If the only way you can keep your blood sugar low is by never eating carbs, you really haven’t cured your diabetes.

Keto vs Vegan for Athletic Performance

Keto diets and vegan diets can both offer some athletic performance benefits when done right.

My overall assessment would be that a vegan diet has more evidence behind it, but this is an area I researched a bit less than the others.

Vegan Diet for Athletes

When looking at vegan diets and athleticism, one of the big benefits is faster recovery (source). Many people are stunned that their bodies heal and recover so much faster on a plant-based diet.

When keto advocate Thomas DeLauer tried making his keto diet 100% plant-based for two weeks, he was shocked by the performance benefits he experienced. Instead of being able to do 18 burpees with his weight vest on, he could do 32 (!), suggesting a dramatic increase in his VO2 max.

Vegan athletes should be mindful of their protein intake, though. Be sure to eat high-protein foods like beans, tofu, seitan, and tempeh.

For an overview of how plant-based diets can benefit athletes, check out the documentary The Game Changers on Netflix.

Keto for Athletes

For keto athletic performance, one of the main claims is that it helps with endurance exercise. When your body is running on carbs, you can “hit a wall” (or “bonk”) after depleting your glycogen stores. But when you start the race in ketosis, you can smoothly keep burning fat for hours, without hitting any “wall” or needing to refuel.

One of the downsides of a keto diet for sports is when it comes to explosive movements. Keto is not generally recommended for sprinters, for example.

To generate maximum force very quickly, you need carbs to burn through anaerobic metabolism (glycolysis). For this reason, some keto athletes do choose to strategically utilize carbs when needed for events.

This article from Healthline covers some of the pros and cons of a keto diet for athletes and a few different professional opinions.

Which Is Easier to Follow: Keto or Vegan?

The best eating plan is one you can stick with for years. You don’t want to follow a perfect diet for one month and then fall off track and be right back where you started.

Keto and vegan are both potentially “hard” diets because they’re both very different from the Standard American Diet. They both involve cutting out whole groups of foods.

In a Women’s Health article, keto was referred to as being “notoriously tough to maintain.” Indeed, one of their takeaway points is that vegan diets are usually easier to sustain—but it can vary from person to person. (source)

The matter of which diet is more sustainable for you is a personal matter. It depends on your food tastes, your social circle, and your personal values.

If you’re someone who believes in environmental or ethical reasons to be plant-based, that can be a great help in sustaining your motivation for a vegan diet because you’re not just doing it for yourself.

Indeed, when I went vegan as a teenager, it had nothing to do with my own health or weight loss. I didn’t want to contribute to the deaths of animals. And that led me into a plant-based diet that has kept me thin and healthy, now into my 30s. I don’t plan on ever quitting veganism!

If your friends are doing keto, you may find it easy to do keto. But if your friends are vegan, it’s going to be easier to stay vegan.

And it should be noted that the most sustainable diet for you may not be a strict keto or vegan diet. I have a full guide to going “flexi-vegan” that may appeal to some people, as well.

Which Is More Affordable, Keto or Vegan?

Both diets—keto and vegan—can be done affordably. There’s nothing inherently expensive about the foods that you’ll eat on either diet.

I know from experience that a vegan diet can be done very cheaply. In college, I lived off of $80 of vegan groceries for a month (USD). Today, I spend more like $200 or $300 for groceries per month because I include more expensive foods like nuts, fresh fruit, and (sometimes) protein powder.

I wrote all about the costs of a vegan diet in this blog post. I also give ideas in that post for how you can do it cheaply if needed! (Again, I know from experience how to do vegan CHEAP.)

When it comes to the cost of a keto diet, one of the concerns may be the meat quality. Many keto practitioners emphasize that you should get grass-fed beef, organic dairy, and so forth. But these will all likely cost you extra.

Still, it is possible to do keto on a budget. Find the most economical form of each food you’re going to eat, considering bulk and frozen options. Avoid the specialty packaged “keto” foods and stick to the basics.

Which Has More Potential Risks and Deficiencies?

Both the keto diet and a vegan diet are quite restrictive, so each one can lead to deficiencies or problems if not done properly.

But after researching this for quite a while, I would argue the risks and common side effects are higher on a keto diet.

Vegan Risks and Potential Deficiencies

I’ve been vegan for 12 years, and I’ve had no major deficiencies or health problems. That said, there are people who run into problems on plant-based diets.

The most dangerous potential deficiency for vegans is vitamin B12. Every long-term vegan should supplement vitamin B12. Luckily, B12 supplements are cheap and come in several forms (sublingual, spray, etc). And since it’s a water-soluble vitamin, there’s not much risk of taking too much—you’ll just pee out the extra.

Some vegans also struggle to get omega-3 fats, which many people get from fish and fish oil. These fats contribute to your brain health, among other things.

You can get some omega-3s from flaxseeds, chia seeds, hemp seeds, and walnuts—but I also recommend vegans take a DHA/EPA supplement made from algae. Those are the actual forms of omega-3 that your body can readily use.

Vitamin D is an interesting one because, really, most people today are low in it—particularly in the winter months with less sun. But this applies to vegans, too: Vitamin D supplementation is a good idea.

My favorite vegan multivitamins. Read my full post on why these are the best hands down.

Recently, I found an awesome solution for getting your B12, omega-3, and vitamin D all at once: Future Kind multivitamins (link to my full review). They’re made specifically for vegans by an all-vegan company. If you’re going vegan, I recommend checking it out!

There’s just one more supplement I take in addition to the Future Kind multivitamin: Zinc.

I started supplementing with zinc about a year ago when I realized that lower zinc levels on a vegan diet could be responsible for the acne I was still getting. Now I recommend zinc to everyone because I actually stopped getting colds, too. Here’s the zinc I take daily (Amazon link).

Some vegans also have problems with iron, calcium, vitamin A, or other nutrients. It’s always a good idea to talk with a doctor or dietitian, or at least consult a vegan nutrition book or website, to make sure you’re doing this right—but most people seem to do well.

Many vegans just have some problems with gas in the first few weeks, especially while introducing more beans. Read my post about stopping vegan farts for help with that.

Keto Risks and Potential Deficiencies

There are many potential risks with a keto diet. Here’s a video that outlines some of the problems dieters can have with it:

I know, a YouTuber named “Mic the Vegan” is probably biased against keto, right? But he cites primary research and sources within the low-carb community to support his points—so at least hear him out.

Even some of the major advocates of keto, like Dr. Stephen Phinny from Virta Health, only recommend a ketogenic diet when it is formulated by and undertaken with the guidance of a physician knowledgeable in it.

Some of the more common issues people experience:

“Keto Flu”: Many people feel pretty bad in the first week or two of going keto, having symptoms like fatigue, irritability, nausea, headaches, brain fog, and constipation. This is “keto flu.” There hasn’t been much actual research on it, but here’s a Harvard Health article about it.

Lack of fiber: Fiber is crucial in building a healthy gut microbiome. And animal products have no fiber whatsoever—it only comes from plants. So, if you’re not including many veggies in your keto diet, you could run into digestive problems. Eat your veggies!

“Keto Diarrhea”: Many keto dieters experience diarrhea, although for some it’s only a temporary problem. Here’s a whole article on keto diarrhea. (Others experience constipation from the lack of fiber.)

Insulin resistance? There’s also the potential to develop insulin resistance on a keto diet, as outlined in the section on diabetes above.

Weight re-gain: The keto diet brings quick weight-loss results for many, but if you can’t sustain the diet long-term, many people end up regaining the weight they lost.

And finally, one more weird side effect that some people experience on keto:

“Keto Crotch“: Yeah… You can read about the details here, but I’ll just say this: Some women experience a particularly bad smell down there after being on keto for a while.

I’m sure my view from the outside is more pessimistic than a dedicated keto practitioner, so by all means, look into other sources! But I think this list is pretty off-putting.

Which Is Better for the Environment and Animals?

A vegan diet was rated the #1 best diet for the environment by Everyday Health.

This is the easiest one to answer: Vegan wins here—and it’s no competition. Veganism is a diet that many people choose specifically for animal rights and environmental reasons.

Even if you choose to buy “ethical” versions of animal products for your keto diet, such as free-range and grass-fed, it doesn’t compare to a vegan diet. Often times, animals are still crowded and suffering to some degree on those “humane” farms.

Keto tends to be a disaster from a sustainability standpoint. The high load of animal products drives methane production and inefficient use of land and water.

When Everyday Health ranked 11 popular diets from most to least environmentally friendly, vegan ranked #1 (best), whereas keto ranked #8 (third to worst).

From an animal rights standpoint, a vegan diet is the only diet consistent with the belief that animals should have rights over their lives and shouldn’t be exploited for human purposes. Read more about that in my big post on vegan ethics.

Is It Possible to Be Vegan AND Keto?

Yes, it is possible to eat a vegan keto diet. To do this, you just need to stay in the macronutrient ranges of a keto diet (around 5% carbs, 20% protein, and 75% fat) while only eating plant-based foods. However, this is a very restrictive diet.

Here’s a video where Thomas DeLauer, one of the leading keto YouTubers, follows a vegan keto diet for 2 weeks.

Personally, I wouldn’t recommend anyone to be strict vegan and strict keto for the long-term. It’s just very restrictive, so it could be socially and psychologically hard to maintain.

That said, for long-term health, a plant-based version of keto is likely far better than a normal keto diet. Indeed, a 2010 study showed that, among low-carb dieters, those who focus on plant sources of fat and protein had 23% less heart disease.

If you do want to be vegan keto, you’d want to focus on these foods:

  • Avocado and avocado oil.
  • Nuts and nut butter.
  • Coconut, coconut oil, coconut yogurt.
  • Tofu, tempeh, seitan, and mock meats.
  • Nutritional yeast.
  • Tons of greens and fibrous (non-starchy) vegetables.
  • Maybe a keto vegan protein powder like Sun Warrior Clean Keto (Amazon link).


  • Keto and vegan can both work for weight loss. On average, keto weight loss may come faster, but vegan weight loss may be longer-lasting.
  • Plant-based diets have more evidence for long-term health. They’re much better for avoiding heart disease, and evidence suggests they’re better for avoiding cancer, diabetes, and overall mortality, too.
  • Either diet should be undertaken with proper planning. If you take medications (like blood pressure meds or insulin), you should have professional supervision.
  • If you go vegan, try to limit high-glycemic carbs like white bread, white pasta, most cereals, and potentially even high-sugar fruits like dates and bananas. Limit processed foods.
  • If you go keto, include lots of fiber-rich vegetables (like greens) and plant sources of fat like nuts and avocado. Do not just eat fatty animal foods and expect to stay healthy.

Two More Recommendations for Your Plant-Based Journey

1. This is the best free video training I’ve found on plant-based nutrition. You’ll learn how to reduce your risk of cancer, heart disease, type 2 diabetes, Alzheimer’s, and obesity—all with plant-based food. Watch the free “Food for Health Masterclass” here.

2. This is the best vegan multivitamin I’ve found in my 14 years of being vegan. It has vitamin B12, vitamin D, omega-3—and nothing else. Translation: It only has the nutrients vegans are actually low in. Read my full review of Future Kind’s multivitamin here (with 10% discount).

If you liked this guide and don’t want to forget anything, save the Pin below to your Pinterest “vegan nutrition” or “plant-based diet” board!