Cod vs. Flounder: 5 Differences & Which Is Better?

Cod and flounder are great protein options to include in your diet. However, based on your goals, one might be better for you than the other. 

As a Registered Dietitian, my job is to guide my clients on which food is better for them.

So, what are the differences between cod and flounder? The main difference between cod and flounder is that cod has 5.4 grams more protein than flounder per 100 g. Cod is also lower in fat (-1.2 g) and has a higher micronutrient profile.

However, flounder is lower in calories (-12 kcal) and higher in omega-3 fatty acids, which help reduce inflammation in the body. 

While I recommend eating cod over flounder, this doesn’t mean flounder is a bad option. It is still an excellent source of lean protein. 

Let’s talk about the differences between cod and flounder so you can decide which is the better option for your goals. 

Cod vs. Flounder: Nutritional Information

The nutritional information in the following table is for 100 grams of raw cod and flounder. 

Calories 

Cod and flounder have similar caloric content, with cod slightly higher in calories (+12 kcal). 

This might not be a significant difference for the majority of people. But for those on a caloric deficit (eating fewer calories than the body needs to maintain weight), 12 calories can be a lot, especially when consuming multiple servings per day.

This means they might opt for flounder due to its lower caloric content. 

Protein

Cod has the advantage of being higher in protein per 100 grams (+5.4 g) than flounder. 

Protein plays an important role in the body. It maintains your muscle mass, keeps your fullness levels high (meaning you won’t feel hungry with a high protein intake), and can slightly increase your metabolism. 

In my experience, most people have trouble reaching their protein requirements. If this is your case, it is better to go with cod since it gives you more protein in the same amount of food. 

However, if you prefer flounder, you need to eat more of it to ensure you get the same protein content. You’d need to increase your portion size to 113 g of flounder to get the same amount of protein that’s in 100 g of cod.

Fats

Flounder has a higher fat content per 100 grams (+1.2 g) compared to cod. 

However, they are both considered a lean protein option since they have less than 5 g of fat per serving size. 

For those looking to decrease their risk of heart disease, decreasing their consumption of saturated fats is important. Cod and flounder are both excellent choices. They each have less than 1 gram of saturated fat per serving. 

Studies have shown that a very large intake of saturated fats (more than 7% of your total daily calories) could lead to heart disease. 

Micronutrients

Another difference between the two fishes is their micronutrient content (how many vitamins and minerals they contain). Cod has a higher micronutrient content than flounder. 

In the following table, you can find the micronutrient composition for cod and flounder. 

Here are the top nutrients cod has and their benefits:

• Selenium. It is a powerful antioxidant that can help reduce inflammation in your body. Also, it plays a role in protecting your heart. A study showed that people with 50% more selenium in their blood had a 24% reduction in heart disease. 

• Phosphorus. Along with calcium, it improves your bone health. It helps regulate how much calcium your body can absorb to help improve bone structure. 

Here are the top nutrients flounder has and their benefits:

• Vitamin B12. Vitamin B12 can prevent the risk of macular degeneration, a disease that can affect your eyesight as you age. In a study, over 5,400 women were given a vitamin B12 supplement for 7 years. Those that supplemented had a 34% decrease in the risk of macular degeneration. 

• Vitamin D. It affects your mood. In a study, people who were supplemented with vitamin D for eight weeks reduced their depression symptoms. However, to get to the amount of vitamin D given to the study’s participants through fish would be ridiculous (more than 13 kg or nearly 29 pounds). So, while flounder is a source of vitamin D, you may also want to consider taking a vitamin D supplement to realize its full benefits (make sure to take a vitamin D blood test to check your levels without supplementing first). 

Cod vs. Flounder: 5 Differences

1. Taste and Texture

One of the differences between cod and flounder is their taste and texture. 

Cod has an intense and sweeter taste. It also has a firmer texture, often compared to chicken. On the other hand, flounder is very moist and has a flaky texture (like tilapia). 

The good thing is that both can be paired with any spice, herb, or sauce of your choice. 

Winner: Tie

They both have delicious tastes and textures which can be paired with any sauce or seasoning. 

2. Cooking Methods

Both cod and flounder are very easy to cook. You can use different cooking methods for them like pan-frying, air frying, or baking. 

Since both fish have a very similar texture, they are fairly quick to cook. Cod typically takes 10-12 minutes to cook, while flounder takes 8-10 minutes. 

Also, keep in mind that if you buy frozen flounder or cod, defrosting times vary. It can take 2-4 hours less time for you to defrost flounder than cod. 

Winner: flounder

While they have similar cooking methods and times, flounder is easier to defrost and faster to cook. 

3. Costs

There is a significant difference in the price of flounder and cod. Flounder is cheaper than cod, with a $3 to $10 difference depending on where you buy it.  

As well, while flounder is cheaper than cod, it is harder to find, meaning it won’t be available in every store. 

The following table compares the price of cod and flounder in some of the top grocery brands in the US. The price is given for one pound of product. 

As you can see, Walmart is the cheapest option, so if you want to cut back on your grocery bill, it is a great place to purchase your proteins. 

There is a big difference in the price of flounder between Wegman’s and the other stores, with this option being the most expensive place to get flounder. Also, in this case, flounder is more expensive to buy than cod. 

Winner: flounder

Flounder is cheaper than cod, but you won’t find it in every store. If you are looking for the most affordable option for both, shop at Walmart. 

4. Omega-3 and Omega-6 Fatty Acids

Omega-3 and omega-6 fatty acids are essential to the body. This means the body cannot produce them, and they must be obtained through the diet. 

Omega-3 has anti-inflammatory properties (meaning it reduces inflammation in the body), while omega-6 has pro-inflammatory properties (meaning it increases inflammation in the body).

Your body needs some inflammation to be able to heal or recover from working out. However, too much inflammation in the body can lead to pain, chronic fatigue, and stomach issues. 

Studies show that the typical diet is higher in omega-6 fatty acids than it needs to be. That is why it’s prevalent for people to have chronic inflammation. The ideal omega-6 to omega-3 ratio is 2:1 (even 1:1). However, in most diets, it’s 16:1. 

Flounder has 253 mg of omega-3, while cod has 195 mg. Even though they are not as high in omega-3 as salmon (2,342 mg), the benefit that both of them have is that they are very low in omega-6. They both have less than 10 mg of omega-6 (salmon has 122 mg), which can help balance the omega-6 to omega-3 ratio. 

Winner: flounder

It has a higher omega-3 content than cod and a low omega-6 amount. 

5. Mercury

Adding fish to your diet might be a concern due to mercury. High mercury levels can lead to fatigue, headache, depression, memory problems, and tremors.

The FDA recommends a maximum intake of two to three 4-ounce portions of fish per week to avoid getting mercury poisoning. 

According to the FDA, cod and flounder are both low in mercury. Thus, they are an excellent option if you’re concerned about mercury content. 

Winner: tie

They are both classified as low in mercury. 

Cod vs. Flounder On Environmental Sustainability

Both cod and flounder can be found wild-caught or farm-raised. Wild-caught fish are caught in their natural habitat, while farmed-raised fish are raised in controlled human environments. 

There are a lot of controversies when it comes to farmed-raised fish. Since fish are grouped into tanks, they are more likely to get sick. This means they are given antibiotics and other medicines to keep them healthy.

These diseases and antibiotics can pollute the water and affect the wildlife near the farms. An increase in disease can lead to other wildlife getting sick, and if they are unable to fight the diseases, it can decrease their population size.

Whenever possible, choose wild-caught over farmed-raised or learn about the farming conditions where you buy the fish. You can do this by asking the fish monger at your fish market or grocery store about the conditions of the fish. 

Cod vs. Flounder on Different Diets

Keto

Cod and flounder can both be included in a keto diet as they are an excellent source of protein.

However, remember that they are low in fat, meaning you need to add a fat source to help you reach your daily fat intake. You can add avocado, olive oil, butter, or nuts. 

Paleo

One of the main benefits of the paleo diet is that it focuses on reducing inflammation in the body. 

While cod and flounder are both excellent options to eat while following a paleo diet, flounder is higher in omega-3 and has a low omega-6 content, making it the ideal option to include in a paleo diet. 

Intermittent Fasting 

A common problem seen in people who do intermittent fasting is that they tend to decrease their protein intake due to the shorter eating window. This is a big mistake since you want a high protein intake to maintain your muscle mass and help increase your fullness levels. 

Cod and flounder are great options to help you achieve your protein intake if you are practicing intermittent fasting.

However, cod has 5.4 more grams of protein per 100 g of fish, which makes it slightly better for keeping protein intake high when intermittent fasting. 

Low-Sodium Diet

Fresh cod or flounder are excellent additions to your low-sodium diet.

However, if you are getting them frozen, you need to be careful with the sodium content, especially if the frozen filets have additional sauces or seasonings. These can add 300-800 mg of sodium per serving. 

Make sure your frozen cod or flounder has less than 150 mg of sodium per serving to ensure you are within the standards of a low sodium diet. 

Vegan

Cod and flounder are not allowed on either a vegan or a vegetarian diet. You can replace them with tofu or seaweed. 

Low FODMAPs

If you have irritable bowel syndrome, including cod and flounder won’t cause any gastric distress since they don’t contain any FODMAPs. 

However, be careful how you cook them since onion and garlic are high in FODMAPs, which can cause bloating or stomach cramps. 

• Related Article: 15 High Calories Low FODMAP Foods

Cod vs. Flounder: Which Is Better For Weight Loss?

Both cod and flounder are excellent options for weight loss since they are high in protein and low in fat.

However, flounder is a better option if you need to pick one since it is lower in calories. You get 70 calories in 100 g of flounder compared to 82 calories in 100 g of cod. 

Nonetheless, this doesn’t mean you cannot have cod on a weight loss journey. Since cod is higher in protein, it can increase your fullness levels, making you feel fuller for longer.

This will allow you to avoid overeating on your next meal or feeling the necessity to snack during the day. 

Cod vs. Flounder: Which Is Better For Muscle Gain?

Cod is a better option than flounder for building muscle since it contains more calories and protein. Cod has 12 more calories and 5.4 g more protein than flounder.

You need a caloric surplus (eating more calories than your body needs to maintain its weight) and the right amount of protein to achieve muscle gain. 

Even though cod is higher in calories than flounder, you might still not reach your total daily calorie intake because it is still low in calories.

You must add other high-calorie foods (like avocado, almonds, cashews, chia seeds, and hemp seeds) to achieve the desired caloric intake.

Practical Recommendations: Eating Cod vs. Flounder

Change Your Foods

A healthy diet includes different foods and allows you to get different nutrients. Don’t rely on only one source of protein.

Ensure you get various protein sources such as tilapia, salmon, tuna, mahi-mahi, chicken, pork, seafood, and red meat. 

Choose The One You Like

If you only like cod or flounder, you don’t need to include the one you don’t like just for the health benefits. The most important thing is to eat foods you enjoy.

Even if cod is the best option, you don’t need to include it if you don’t like it. Eating should be something that you enjoy, not something that brings you negative emotions. 

Track Everything

No matter which protein option you choose, keep track of the food you eat, especially if you have a weight loss or muscle-building goal in mind.

One of the most common problems my clients have is eyeballing their protein sources and not hitting their protein requirements. 

To ensure you reach your goals, use a food scale to weigh your portions and keep track of what you eat in a calorie tracking app.

This can also tell you how much you need to compensate for flounder being lower in protein. You can adjust it by including other high-protein foods (Greek yogurt, cheese, chicken, or seafood) or adding more flounder to your dish. 

Try Different Recipes

One of the most common reasons people don’t include fish in their diet is because they don’t know how to cook it.

The advantage of fish is that you can cook it in several ways. You can use different herbs, spices, and cooking methods to add some variety to your diet. 

Here are some recipes for you to try: 

• Baked cod
• Baked cajun garlic butter cod
• Baked flounder with lemon and garlic 
• Garlic parmesan flounder

Other Fish Comparisons

• Tilapia vs. Salmon
• Cod vs. Tilapia
• Flounder vs. Tilapia
• Cod vs. Salmon
• Halibut vs Salmon
• Halibut vs Flounder
• Tuna vs. Mahi Mahi
• Mahi Mahi vs. Cod