Vegetarian vs Vegan vs Pescatarian: Diet Comparison


Maybe you want to reduce your environmental impact.

Maybe you’re trying to be healthier.

Or maybe you have ethical concerns about eating meat.

These 3 diets may all be options for you.

But which one is best for you?

I’ve created a detailed, but simple comparison of these diets on this page. By the end, you should have a clear idea of the positives and negatives of each diet and which one is most suited for you.

This is a vegan blog, but this is my best attempt at an objective look at the diets. I applaud you for trying to make a positive change in your diet either way.

Vegetarian vs. Vegan vs. Pescetarian – What Do They Eat?

Let’s start with the basic, what do each of these terms mean?

There are multiple types of vegetarians, but for this page I’ve assumed the standard and most common type, lacto-ovo vegetarian.

Here’s what each diet consists of.

Do they eat… Pescetarian Vegetarian Vegan
Meat No No No
Fish Yes No No
Eggs May or May not Yes No
Dairy May or May not Yes No
Plants Yes Yes Only!

In other words:

  • Vegans are simple, we eat plants and nothing else.
  • Vegetarians typically eat plants, plus eggs and dairy. There are other specific types of vegetarians that may omit one or the other.
  • Pescetarians aren’t officially a type of vegetarian, but many consider them similar. They don’t eat meat, but do eat fish. Some also avoid eggs and dairy, while other pescetarians eat them.

Potential Health Risks and Benefits of Each Diet

All of these diets are usually going to be healthier than a standard omnivorous diet.

Technically you could just eat junk food (on any of these diets) and be very unhealthy, but not many people do that (partly because junk food is less available for vegans and vegetarians).

Over time, it’s looking more and more like meat is unhealthy. The type (red vs others) and amount is going to be important, but in general, less is better.

Studies are finding that red meat consumption in particular is linked to heart disease and cancer. It’s a bit tricky to conclude, because people that eat a ton of meat tend to be the types that aren’t trying to be healthy in the first place.

Regardless, governments have started to update their eating recommendations to reflect this.

Canada for example, released a new Food Guide that puts a lot more emphasis on plants, and less on meat.

canada food guideline

This is most similar to a flexitarian diet (pretty new term), where people eat meat, but not too often.

So picking any of these 3 diets is likely a healthier option than an omnivorous diet.


The most recent evidence suggests that diets that limit meat intake are healthier than a standard omnivorous diet. That’s why many people see health benefits after switching to pescetarian, vegetarian, or vegan diets.

Pescetarian Health Risks and Benefits

health effects of fish

Both the health risks and benefits of being pescetarian revolve around fish.

Fish is very nutritious. Lots of protein, and more importantly, the best source of omega 3 fats (aside from algae, but honestly who eats algae?). These fats are known to improve heart, brain, and eye health.

You can get omega 3 fats from plant sources, but it’s harder and typically in much smaller amounts.

But, eating fish does come with a risk, specifically mercury toxicity.

In general, the larger the fish, the more mercury it will contain.

Here are the Canadian guidelines for fish consumption in regards to mercury (a serving is about 75 grams):

  • Adults: 150 grams per week.
  • Pregnant or breastfeeding women: 150 grams per month.
  • Children 5-11 years old – 125 grams per month
  • Children 1-4 years old – 75 grams per month

So even if you’re pescetarian, you shouldn’t be eating fish every day.

Certain types of fish have less than others. For example, canned tuna is usually made from younger (not grown) tuna, and have a lot less mercury than fresh or frozen tuna.

You’ll need to do more research about the fish in your country, and think about the types of fish you eat if you choose this diet option.


If you’re eating mostly vegetables, you’re off to a good start. In general, adding small amounts of fish (1-2 times per week) could provide healthy benefits through omega 3 fats, while not putting you at risk of side effects from mercury consumption.

Vegetarian Health Risks and Benefits

A lacto-ovo vegetarian’s health risks and benefits focus around eating eggs and dairy.

Eggs are generally pretty healthy. They have a ton of vitamins and minerals. There are concerns about the high cholesterol content, but the research is pretty unclear about if it’s bad or not.

Dairy is just as controversial. A fairly recent meta study found that there’s no evidence of negative health effects from consuming dairy, and even a few benefits.

However, most of the authors of that paper have a few clear conflicts of interest. For example:

  • Anne Raben is has research funding from the Dairy Research Institute.
  • Tine Tholstrup has gotten research grants from the Danish Dairy Research Foundation and the Dairy Research Institute.

That doesn’t invalidate the results, but it’s easy to see how they could be bias (whether consciously or not).

The study claims they looked at “the totality of available scientific evidence”, but they excluded studies like:

  • This one, which found that replacing dairy fat with vegetable fats may reduce the chance of heart disease.
  • This one, which found that there was no correlation between calcium intake and risk of fractures (there are other factors that influence calcium absorption and are apparently more important).

As always, single studies don’t tell a whole story.

Overall, it seems that dairy is safe to drink with minor benefits or side effects at most.

Obviously this changes if you’re lactose intolerant. Also keep in mind that milk has quite a lot of sugar, so you probably shouldn’t be drinking too much.


Having vegetables as the core of a vegetarian diet makes the average vegetarian diet healthy. While controversial, eggs and dairy don’t seem particularly healthy or unhealthy, as long as you’re not consuming a crazy amount.

Vegan Health Risks and Benefits

health concerns of vegan diets

Has any doctor ever recommended eating fewer vegetables?

Not that I know of.

And the best protein sources for vegans, legumes, are full of protein, fiber, and minerals.

So it seems that eating an all plant diet is pretty darn healthy.

But that being said, there are some risks of a vegan diet that all vegans should be aware of.

The biggest risks are:

  • Vitamin B12 deficiency – You can’t get B12 from plants (unless you eat them without washing them). All vegans either need a vegan vitamin B12 supplement, or to eat foods fortified with B12. It’s not hard to get, but it’s important for neurological health.
  • Iron deficiency – There’s iron in lots of vegan foods, but new vegans in particular often don’t get much (or enough) iron. You either need to pay special attention to iron (just until you get used to the diet), or take a vegan iron supplement on a regular basis. Personally, my iron levels are higher than as an omnivore (checked when I give blood), and I don’t use a supplement.
  • Stomach problems – Many new vegans get stomach problems because there’s so much fiber in most vegan diets. This passes as you get used to it.
  • Vitamin D deficiency – Not an issue if you get a decent amount of sun, but if you work night shifts or live in a dark place it can be (although not only for vegans). There are vegan vitamin D supplements if needed.

Assuming you pay attention to the nutrients in your specific diet as a vegan, you’ll be about as healthy as you can be. There’s no serious health risk that vegans are more at risk for than anyone else.


Vegan diets are very health if planned correctly. You need to make sure to get enough vitamin B12, vitamin D, and iron, whether through food or supplement sources.

Which Diet Is Best for You?

Putting ethics aside completely, the best diet for you will depend on what you’re trying to achieve.

For example, if you’re trying to lose weight, a typical vegan diet will have the least calories of all 3. However, you can lose weight on any diet, as long as you track your calories.

The best for overall health is debatable if you had an ideal diet for each. In reality, they’re all pretty similar in terms of healthiness, and are better choices than a meat-heavy typical Western diet.

The biggest factor in how healthy each diet will be for you is what you choose to eat. You can find junk food that fits each diet, and if you choose to eat a lot of it, your overall diet still won’t be particularly healthy.

Finally, consider cost and how likely you are to stick with it. Pick the diet you think works for you the best, and don’t be afraid to take some time to try out different diets if needed.

Vegetarian vs. Vegan vs. Pescetarian: Environmental Impact

All 3 of these diets have a much lower environmental impact than a typical diet with meat in it.

The graph below from Our World in Data shows the greenhouse gas emissions of common proteins.

greenhouse gas emissions of various proteins

It’s clear that while meat is the worst in terms of emissions, dairy and fish are both significantly higher than plant-based protein sources as well.

In other words, a vegan diet is likely to produce the lowest emissions of any of these diets.

A typical vegetarian diet will have a similar level of emissions as a pescatarian diet (the average of eggs plus milk above is similar to fish).  

About the author

Dale Cudmore

Your friendly neighborhood vegan from Toronto. Chemical engineer turned semi-professional soccer player and freelance nutrition writer. I've been vegan for years and try to make life easier for others by sharing what I've learned.