“A pescatarian diet is one that prioritizes fish and seafood as the primary protein source,” says the Kansas City–based registered dietitian Cara Harbstreet, the author of The Pescatarian Cookbook: The Essential Kitchen Companion. If you’re following this diet, you may also choose to include eggs and dairy in your meals and snacks. This is not an all-fish diet. Harbstreet says pescatarians typically have two or more seafood meals per week. The remainder of the meals and snacks are plant-based and are similar to a Mediterranean-style of eating.

What to Eat

FishShellfishEggs (optional)Yogurt (optional)Cheese (optional)Milk (optional)Beans and legumesTofuVegetablesFruitNuts and seedsWhole grains (whole-grain pasta, bread, and brown rice count)

What to Avoid

PoultryBeefLambPorkDeli meatBacon

Are Some Fish Better Than Others in a Pescatarian Diet?

It’s important to choose sustainably sourced fish whenever possible. As a resource, Hallissey recommends the Monterey Bay Aquarium Seafood Watch, which features downloadable and printable buying guides by area. If you’re going for canned fish, she recommends the Wild Planet line, which sources fish sustainably and carries tuna, salmon, sardines, mackerel, and more. Lunch Salad topped with salmon, feta, pine nuts, and vinaigrette Dinner Quinoa stir-fry with vegetables Snack Plain Greek yogurt topped with blueberries

Day 2

Breakfast Chia pudding made with almond milk, topped with berries and nuts Lunch Minestrone soup with a whole-grain roll Dinner Black bean burger with side salad Snack Guacamole with whole-grain tortilla chips

Day 3

Breakfast Homemade whole-grain banana muffin Lunch Vegetarian couscous salad Dinner Tofu and vegetable curry over brown rice Snack Pear and cheese slices

Day 4

Breakfast Eggs cooked in an avocado Lunch Falafel in whole grain pita with tomatoes, cucumbers, and tzatziki Dinner Crab cakes with steamed broccoli and wild rice Snack Sliced vegetables and hummus

Day 5

Breakfast Whole-grain waffles with nut butter Lunch Caprese salad Dinner Fish tacos with black beans Snack Kale chips

Day 6

Breakfast Baked oatmeal with nut butter and fruit Lunch Lentil, vegetable, farro grain bowl Dinner Zucchini lasagna Snack Pumpkin seeds and watermelon cubes

Day 7

Breakfast Yogurt drizzled with honey and berries Lunch Roasted vegetables sandwich and an apple Dinner Tuna avocado rolls with side salad Snack Roasted chickpeas

Yet the opposite can happen, says Melissa Mitri, RD, the owner of Melissa Mitri Nutrition in Milford, Connecticut. “It’s easy as a plant-based eater to become more of a “carb-eterian,” where you don’t eat meat but your diet is heavy on refined carbs that promote weight gain,” she says. “It’s important to follow a pescatarian diet properly to increase your chances of weight loss success.”

“People have an impression that cooking fish is difficult and elaborate, but in fact, it’s easier than chicken,” says Hallissey. One fear is undercooking, and it’s common to swing in the other direction and totally overcook the fish, leaving it dry and unpalatable — and leaving you wondering why you’re even trying this in the first place. Hallissey suggests learning a few easy techniques for cooking — like baking a fillet on a pan with veggies for a one-pan meal, or drizzling fish in olive oil, salt, and pepper, and sautéing in a pan (don’t forget to flip). Canned fish, like sardines, light tuna, and salmon are great options, as they’re inexpensive and already cooked, requiring no prep.

If you have any concerns or have eliminated entire food groups while on this diet, speak with a registered dietitian or your doctor to see if you need to be tested for nutrient deficiencies. The Seafood Watch program guides you toward sustainable seafood choices with their “best choice,” “good alternative,” and “avoid” labels for various fish varieties. You can download it to your phone for easy access when at the grocery store or a restaurant. Natural Resources Defense Council Mercury in Fish Wallet Card Download and print out this handy wallet card, which sorts fish by mercury content, something that’s especially important to track if you’re pregnant or are feeding fish to your children. You’ll get a list of fish that are low, moderate, high, and highest (to avoid) in mercury.

Books on the Pescatarian Diet

The Pescatarian Cookbook: The Essential Kitchen Companion This book, by the registered dietitian Cara Harbstreet, is a top pick for anyone who has considered themselves a pescatarian for a while or are just getting into the diet. Harbstreet dives into the health benefits, then tells you how to build a pescatarian kitchen and master meal planning. Her recipes are a mix of seafood and pescatarian main dishes, along with breakfasts, soups and salads, and sides. Some must-try recipes? Sea Breeze Salmon Salad, Pan-Seared Trout, and Black Bean Tostadas.

Blogs on the Pescatarian Diet

The Posh Pescatarian Helmed by Stephanie Harris-Uyidi, who calls herself a “sustainable seafood enthusiast,” this site is where you’ll learn all about how to make delicious fish and seafood recipes at home — even if you’re a beginner. Check out her Mahi Mahi Fish Tacos, Lobster Claws with Lemon-Infused Ghee, Pescatarian Oyster Pan Roast, and more restaurant-worthy creations.

App for Following the Pescatarian Diet

Lifesum (Available for download on the Apple Store and Google Play) This food app can help you stay on track with your nutrition as you embark on a new way of eating on the pescatarian diet. Among the features: a food diary, a macronutrient tracker, and integration with fitness apps. You’ll also want to tap into their recipe library and save your favorite fish meals for later reference.