Are Oysters Keto? (Hint: the Answer is YES!)

Are Oysters Keto

A ketogenic (keto) diet is very low in carbohydrates and high in fat. Keto diets are loaded with meat, poultry, eggs, and seafood because they’re free of carbohydrates, and some are also high in fat. When you think of oysters you probably think along those lines and assume they’re free of carbs. You might be surprised to hear that oysters contain some carbs, so it takes some sleuthing to determine if they’re keto-friendly.

Oysters are considered keto-friendly. Oysters do contain small amounts of carbohydrates and like many low-carb food, eating large amounts can make them not keto-friendly. If you’re following a strict keto diet, oysters may not be the best fit. The best keto-friendly alternatives include Wild Planet Wild Sardines, Wild Planet Wild Pink Salmon, and Public Goods Sustainably Caught Skipjack Tuna.

Why do oysters contain carbs, and what are the potential benefits of eating them? Read on to learn all about oysters, as well as some other keto options if you’re not a fan.

What are oysters?

Oysters are a type of mollusk, which includes snails, slugs, mussels, and octopi. There are several types of oysters, but the most popular are Olympia Oysters, Kumamoto Oysters, European Flats/Belon Oysters, Sydney Rock Oysters, Pacific Oysters, and Atlantic Oysters.

All oysters are capable of forming pearls, which form when an irritant enters the oyster. As a protective mechanism, the oyster secretes a fluid to coat the irritant. Over time, the luminous smooth pearl is the result.

What are the nutritional benefits of oysters?

1. Omega-3 fatty acids

Oysters are rich in unsaturated fats, which is unique because animal-derived protein is usually high in saturated fat. Unsaturated fatty acids are known as “heart-healthy” because they promote healthier cholesterol levels compared to saturated fat.

Omega-3 fats are a type of unsaturated fat. They’re well-known for their role in helping to fight inflammation and promoting health in many other ways.

2. Iron

Oysters are a good source of iron, a mineral that helps build protein in red blood cells. Without enough iron in the diet, iron-deficiency anemia can occur, causing fatigue and weakness. It’s estimated that 10-20% of women develop iron deficiency anemia at some point.

3. Vitamin B12

Six medium oysters provide well over 100% of the daily requirement for vitamin B12. Vitamin B12 helps form red blood cells, supports healthy nerve function, and helps produce DNA. Vitamin B12 deficiency can cause a decrease in red blood cells, leading to fatigue, headaches, and impaired balance.

4. Selenium

A 100-gram serving of oysters provides over 90% of the RDA for selenium. Selenium helps protect your cells from damage, supports reproductive health, helps your thyroid function, and more.

5. Zinc

Oysters provide over 600% of the daily value for zinc per 100-gram serving. Zinc helps support your immune system, which is why it’s an active ingredient in immune health supplements. Zinc helps you heal from wounds and helps give you your sense of smell and taste.

6. Copper

100 grams of oysters gives you over 200% of the daily amount of copper. Copper helps support your immune system, nervous system, and helps support brain health.

7. Protein

Oysters are a great source of protein, similar to other types of seafood. Protein helps keep you satiated which can also help with weight loss. Protein is also important for wound healing and the formation of healthy muscle tissue.

What are the nutritional downsides of oysters?


Canned smoked oysters contain sodium to help keep them shelf-stable. Sodium in the diet can add up quickly and worsen chronic health conditions like high blood pressure and kidney disease.

Potential foodborne illness

Oysters are mainly eaten raw to preserve their natural flavors. Eating them raw draws a risk of developing foodborne illness from Vibrio vulnificus and Vibrio parahaemolyticus bacterium.

Who should avoid eating oysters?

  • Oysters are considered shellfish, so they aren’t suitable for people with shellfish allergies.
  • People taking zinc supplements should avoid eating large amounts of oysters regularly to avoid potential zinc toxicity.
  • Pregnant women, people with weakened immune systems, and children should avoid eating raw oysters due to the risk of foodborne illness.

A quick refresher on the ketogenic diet

The ketogenic (keto) diet is a very low carbohydrate diet. Most keto diets contain fewer than 50 grams of carbohydrates per day, while stricter keto diets might limit carbs to around 20 grams per day.

The ketogenic diet is high in fat (70-80% of total calories) and moderate in protein. When you restrict carbohydrates and rely on fat for your energy, your body goes into ketosis. Ketosis is a metabolic state where your body burns fat for fuel instead of carbs.

Potential benefits of following a keto diet include weight loss, improved blood sugar levels, and increased insulin sensitivity. However, the long-term benefits of the ketogenic diet have yet to be studied.

How can I tell if a food is keto-friendly?

Some foods have a keto stamp on them to make it easy to determine if it’s keto-friendly. However, most foods won’t necessarily have this stamp even if they are keto-friendly.

In general, keto-friendly foods are low in net carbohydrates and low in/free of added sugar.

Net carbohydrates are the amount that impacts blood sugar levels and ketosis. To determine the net carbs, subtract dietary fiber from total carbs. Most keto-friendly foods will contain around ten or fewer grams of net carbs per serving, but that isn’t a set-in-stone rule.

Are oysters keto?

Oysters are low in carbs when eaten in moderate amounts, so are generally keto-friendly. However, if you eat a large number of oysters and are on a stricter keto diet, you might find that they provide too many carbs.

Why do oysters contain carbs?

Most meats from animals and fish don’t contain any carbs. Oysters contain a small number of carbs – around 4 grams or less per most servings of canned oysters. It’s thought to be the glycogen (stored sugar) in oysters that provide the carbs.

Oyster Nutritional Information

Crown Prince Smoked Oysters


  • Smoked Oysters (Mollusks)
  • Olive Oil

Nutrition facts (per 65 g drained can):

  • Calories: 150
  • Total Fat: 10 g
  • Saturated Fat: 2 g
  • Sodium: 120 mg (5% DV)
  • Total Carbohydrate: 4 g
  • Protein: 11 g

Pacific Pearl Fancy Smoked Oysters


  • Smoked Oysters
  • Cottonseed Oil
  • Salt

Nutrition facts (per 1 drained can 85g)

  • Calories: 100
  • Total Fat: 4.5 g
  • Saturated Fat: 2 g
  • Sodium: 210 mg (9% DV)
  • Total Carbohydrate: 2 g
  • Protein: 18 g

Chicken of the Sea Whole Oysters


  • Whole Oysters
  • Water
  • Salt

Nutrition Information (per 1 can drained 142 g.):

  • Calories: 150
  • Total Fat: 4 g
  • Saturated Fat: 1.5 g
  • Sodium: 520 mg (23% DV)
  • Total Carbohydrate: 5 g
  • Protein: 23 g

Keto-friendly oyster alternatives

If you’re not into oysters, there are plenty of other keto-friendly seafood for you to choose from.

Wild Planet Wild Sardines

Wild Planet Wild Sardines in Water, 4.375 Ounce - 12 per case. Sardines are a great source of omega-3 fatty acids, which help fight inflammation, support brain health, and can promote healthy cholesterol and blood fat levels. These sardines are sustainably caught in the North Pacific.


  • Sardines (Sardinops Sagax Or Sardinops Melanostictus)
  • Organic Extra Virgin Olive Oil
  • Water
  • Sea Salt
  • Aqueous Natural Smoke

Nutrition facts (per 3 ounces):

  • Calories: 170
  • Total Fat: 11 g
  • Saturated Fat: 3 g
  • Sodium: 260 mg (11% DV)
  • Total Carbohydrate: 0 g
  • Protein: 18 g

Wild Planet Wild Pink Salmon

Wild Planet, Wild Pink Salmon, 6 Ounce, Pack of 12 Salmon is an excellent source of heart-healthy omega-3 fatty acids. Even though this salmon is canned, it isn’t as high in sodium and other canned seafood like anchovies.


  • Wild Pink Salmon
  • Salt

Nutrition facts (per 2 oz):

  • Calories: 60
  • Total Fat: 1 g
  • Saturated Fat: 0.3 g
  • Sodium: 200 mg (8% DV)
  • Total Carbohydrate: 0 g
  • Protein: 12 g

Public Goods Sustainably Caught Skipjack Tuna

This tuna is sustainably caught and ideal for Paleo, Keto, and Whole30 diets. It doesn’t contain any added oils or fillers – just fish and sea salt.


  • Skipjack Tuna (Katsuwonus pelamis)
  • Sea salt

Nutrition facts (per 2 ounces.):

  • Calories: 60
  • Total Fat: 0.5 g
  • Sodium: 230 mg (10% DV)
  • Total Carbohydrate: 2 g
  • Total Sugars: 0 g
  • Protein: 14 g

Bottom Line

Oysters are very low in carbohydrates but are higher in carbs than other seafood like fish and shrimp. Because they contain some carbohydrates, they might not be considered as keto-friendly as other protein sources.

If you don’t eat large portions of oysters, they’ll more than likely fit just fine into a keto diet since they aren’t a significant source of carbs.

Related Questions

Are oysters good for you?

Oysters are good for you! Oysters are a source of healthy omega-3 fats, protein, and are loaded with several beneficial nutrients. To minimize the risk of foodborne illness, oysters should be cooked instead of eaten raw, which is a popular method of eating them.

Are oysters an aphrodisiac?

Oysters are one of several foods thought of as aphrodisiacs, which are believed to help boost sexual desire. However, there is “no to little scientific confirmation” on this topic to confirm if oysters do help boost your sex drive.

Are oysters alive when you eat them?

If you eat raw, fresh oysters, chances are they might still be alive when they’re on your plate. Keeping them alive or killing them shortly before eating is thought to preserve natural flavors as well as iron.

Are oysters vegan?

Oysters aren’t vegan because they’re living beings, which vegans abstain from eating.

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Diana Gariglio-Clelland

Diana Gariglio-Clelland is a Registered Dietitian and Certified Diabetes Care and Education Specialist. She obtained her Bachelor's in Nutrition from the University of Idaho in 2012 and has worked in clinical, community, and primary care nutrition settings. She currently works as a freelancer on various health- and nutrition-related projects.

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