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:

• Weight loss
• Longevity
• Heart health
• Cancer
• Diabetes
• Athletic performance
• Cost and difficulty
• Risks and deficiencies
• Environmental impact

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

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.)

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.

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