Pescatarian vs. Vegetarian Diet: What’s the Difference?

Pescatarian and vegetarian diets are popular for health and environmental reasons. Both diets exclude meat and poultry, but pescatarians eat seafood and vegetarians do not.

People following a pescatarian diet may find it easier to get high-quality omega-3 fats, vitamin B12, and protein than when eating a vegetarian diet. Vegetarian diets may work better for people who don’t like seafood or choose to eliminate it for environmental or ethical reasons.

Both diets center around nutritious plant foods like fruits, vegetables, legumes, nuts, seeds, and whole grains. However, they can still include foods rich in sodium, added sugars, and saturated fat, which can raise one’s risk of chronic (long-term) conditions like type 2 diabetes and heart disease. 

Pescatarian and vegetarian diets both exclude red meat and poultry. They also usually exclude gelatin and lard, which are made from animal collagen and pork fat. Some vegetarians and pescatarians eat products made with gelatin or lard (e.g., jello). 

Both diets focus on plant foods like vegetables, fruits, whole grains, legumes, seeds, and nuts. They tend to be high in fiber, vitamins, minerals, and antioxidants. They might include dairy products like eggs and milk, which provide protein, vitamin D, and calcium.

The main difference between a vegetarian and a pescatarian diet is that a pescatarian diet includes seafood and a vegetarian diet does not. Otherwise, they are the same.

When following a pescatarian diet, it may be easier to get enough omega-3 fatty acids, vitamin B12, iron, and vitamin D. That’s because fish—especially fatty fish like salmon—are rich in these nutrients. Plus, the omega-3s, vitamin B12, and iron in fish are easy for your body to absorb. You can get these nutrients from plant foods, but your body can’t absorb them as efficiently.

Vegetarians who rely on plants for protein may eat more fiber. This helps balance blood sugars, protect heart health, and support gut health.

Following a vegetarian or pescatarian diet is linked with many health benefits. Studies show that vegetarians and pescatarians have a lower risk of overall, prostate, and colorectal cancer (cancer of the colon or rectum) compared to people who eat meat.

Research shows that vegetarians are less likely to develop diabetes than people who eat meat. A vegetarian diet may help lower cholesterol, blood pressure, and visceral fat. The diet is also linked with a lower risk of being diagnosed with and dying from cardiovascular disease.

Whether you’re vegetarian or pescatarian, cutting out or reducing your meat intake can help lower cholesterol and blood pressure. This reduces your risk of heart disease and stroke.

Pescatarian diets have the unique benefit of being high in the omega-3 fatty acids EPA and DHA. These nutrients found in fatty fish have proven benefits for heart health, insulin sensitivity, and inflammation. They’re also important for overall brain health, including learning and memory. Studies show that a pescatarian diet is generally healthier than a vegetarian diet.

Although cutting meat out of your diet can have many benefits, it’s important to consider the health risks, costs, and environmental impacts of switching to a vegetarian or pescatarian diet.

Health Risks

A vegetarian diet increases your risk of vitamin B12, iron, or zinc deficiency. Many plant foods contain iron and zinc, but your body can’t absorb them as well as it can from animal products. Pairing iron with vitamin C-rich foods like broccoli or citrus fruits can help improve absorption.

You may also have difficulty getting enough calcium and protein if you don’t eat dairy products. Eating plenty of plant proteins like tofu, beans, and nuts is important.

Pescatarians have a lower risk of nutrient deficiencies because fish contains highly absorbable protein, vitamin B12, iron, zinc, and vitamin D. However, they might be at an increased risk of mercury poisoning. Most adults can safely eat fish multiple times a week. To be safe, prioritize low-mercury fish like salmon, trout, herring, chub mackerel, and sardines.

If you follow a pescatarian diet while pregnant or nursing, be careful about eating fish high in mercury because it can harm your baby. The U.S. Food and Drug Administration (FDA) recommends eating 2-3 servings of low-mercury fish weekly. You can also eat one serving of fish per week from the FDA’s “good choices” list, which includes grouper, halibut, snapper, and tuna.

Like other diets, eating too many processed foods that are low in fiber and high in added sugars, saturated fat, and sodium can raise your risk of high cholesterol, type 2 diabetes, high blood pressure, and heart disease.

Cost

You can follow a vegetarian or pescatarian diet while still keeping costs low. Vegetarian protein sources like beans, lentils, peanuts, and tofu are often more affordable than meat. 

Fresh fish and shellfish can be more expensive than meat. However, frozen or canned seafood can be a more affordable option.

Here are some tips to help you save money:

• Buy frozen vegetables and fruits
• Buy grains like rice and quinoa in bulk
• Buy canned legumes and fish
• Choose seasonal, local produce if buying fresh
• Cook larger amounts of food and freeze the leftovers
• Choose whole plant proteins (like beans) rather than meat substitutes (like vegan “chicken” nuggets)

Environmental Impact

Many people choose to eat a vegetarian or pescatarian diet to help protect the environment. If your top priority is the environment, research shows that a vegetarian or vegan diet is best. On average, a vegetarian diet leads to 35% lower greenhouse gas emissions than diets that include meat, while a vegan diet leads to 50% less emissions than diets with meat. 

Pescatarian diets can harm the environment due to unsustainable fishing practices like overfishing. Some fishermen may also use inappropriate gear, which can damage the ocean habitat. To minimize your environmental impact from eating seafood, use the Monterey Bay Aquarium’s Seafood Guides to find sustainable fish options.

If health is your top priority, then a pescatarian diet is a great option. It’s less restrictive than a vegetarian diet and has a lower risk of nutrient deficiencies. Eating fish can also make it easier to meet your protein needs, especially if you don’t like plant proteins like beans and tofu.

A vegetarian diet may be a better choice if you want to cut out meat for environmental reasons. Studies show that vegetarian and vegan diets have the lowest environmental impact. If you still want to eat fish, purchase fish that has been sustainably sourced.

You can also choose to take a flexitarian approach, where you primarily eat plant foods and occasionally eat fish or meat. This gives you the flexibility to eat some meat while centering your regular diet around fruits, vegetables, legumes, nuts, seeds, and whole grains. A flexitarian diet is still better for health and the environment than a meat-heavy diet.

Starting a new diet can be challenging, especially if you eat a lot of red meat and poultry. Here are some ideas to ease into a vegetarian or pescatarian diet:

• Look for new plant-based recipes or make your favorite meals with meat alternatives
• Start by making a few breakfasts, lunches, and dinners without meat per week
• Make sure each meal has a protein source like beans, tofu, nuts, or fish—for example, replace steak with salmon, or a beef burger with a black bean burger
• Slowly transition into making most or all of your meals meat-free

Working with a registered dietitian (RD) can help you learn how to prepare well-rounded meals that fit your new dietary restrictions. They may also recommend supplements if you need help getting a certain nutrient, like vitamin B12.

Pescatarian and vegetarian diets exclude red meat and poultry, but pescatarians eat seafood and vegetarians do not. Both diets can support heart health, lower cancer risk, and help prevent type 2 diabetes.

Both diets are popular for health and environmental reasons. A pescatarian diet may be better for overall health, as eating fish makes it easier to get more protein, vitamins, and omega-3s, but it has a bigger environmental impact. Vegetarian diets are better for the environment, reducing greenhouse gas emissions and avoiding unsustainable fishing practices.

If you need support adopting a vegetarian or pescatarian diet, speak with a healthcare provider or RD for guidance.