Is Tuna Good For Weight Loss Or Fattening?

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Find out whether tuna is good for weight loss or fattening so you don’t mess up your diet with the wrong choices.

Tuna is reasonably low in calories, high in protein, high in vitamins and minerals, and unfortunately high in mercury.

When it comes to the more standard nutrients, you can definitely say tuna is generally good for weight loss.

Eating more of this fish type will likely make you feel full enough to avoid foods that are worse for weight loss.

Additionally, the high amount of protein will help you preserve and build muscle which will benefit your energy burning throughout the day.

That being said, due to the high amount of mercury, you really want to limit or remove tuna intake from your diet.

Especially if you are in a category of people where you want to be extra careful with nutrition.

Luckily, many types of fish are good for weight loss. You should be able to find low-mercury alternatives that you enjoy too.

Calories in tuna

The total number of calories in foods like tuna is not the only important detail for weight loss but it does offer helpful information.

An example of cooked tuna contains around 176 calories per 100 grams (1). One can of drained tuna (79 g) contains about 139 calories.

Other species and/or parts of tuna can vary slightly in terms of calories (and other nutrients).

While vegetables and fruits tend to be even lower, it is fair to say that tuna is reasonably low in calories.

Even compared to certain other types of fish.

Next, looking at what sources these calories come from will help you get a better idea of how good tuna is for weight loss.

Protein in tuna for weight loss

Protein is one of the macronutrients in tuna that is the most relevant for weight loss.

Before going into why this is, tuna contains around 30.3 grams of protein per 100 grams (1).

This is an extremely high amount of protein.

Tuna is even impressive compared to other high protein fish.

The first reason this is generally helpful when losing weight is that protein is relatively filling.

Since hunger and cravings are common stumbling blocks when getting in shape, this aspect can be valuable.

Additionally, the protein in tuna will help you preserve and/or build muscle.

Lastly, the human body tends to use slightly more energy to process protein than other macronutrients.

In short, tuna contains a lot of protein which is generally good for weight loss.

Micronutrients in tuna for weight loss

Vitamins and minerals in tuna

It is hard to put into exact numbers to what extent vitamins and minerals benefit weight loss.

At the same time, since many of these play a role in metabolism in one way or another, it is worth taking a look at what tuna offers in this area.

100 grams of cooked tuna contains the following vitamins and minerals (1):

  • Niacin: 115% of the DV (Daily Value)
  • Selenium: 112% of the DV
  • Vitamin B6: 54% of the DV
  • Vitamin B12: 39% of the DV
  • Phosphorus: 35% of the DV

And many other vitamins and minerals in smaller amounts.

It is fair to say that tuna is a powerhouse when it comes to vitamins and minerals.

This is generally a positive point when trying to lose weight (and getting healthier).

The problem with tuna: mercury

So far, tuna is impressive in a variety of areas. Not just for weight loss but also for general health.

However, one important thing to keep in mind with fish like tuna is their mercury content.

Mercury is a substance that is present in certain types of fish more than others.

This is not good since mercury can be harmful to your health.

Some types of tuna are worse than others but this is a fish where mercury content tends to be high.

For certain groups of people like pregnant women, high mercury foods are out of the question.

For others, the recommendations vary.

If you want to play it safe, you would avoid tuna altogether.

Another option is implementing as much portion control as you and/or certain organizations deem acceptable.

Will tuna help you lose weight?

Tuna is reasonably low in calories, high in protein, high in vitamins and minerals, and unfortunately also high in mercury.

Mercury aside, tuna would be a great option for losing weight.

By eating more of it, you feel a lot fuller which tends to help you consume less of foods that are worse for weight loss.

Additionally, the extra protein can help you preserve and/or build muscle which in turn, offers weight loss benefits.

However, because of the mercury, some categories of people want to avoid tuna.

Even if you are not in these specific categories, you could play it safe and stick to other types of fish or food sources.

How to eat tuna for weight loss

Even if a food type like tuna is helpful for weight loss, how you eat it will influence your results a lot.

Some of the best ways to eat tuna for weight loss include:

  • Boiled or baked on its own
  • In a salad
  • As the main protein source of a dinner with vegetables
  • Soup

These types of recipes apply to conned tuna too.

On the other hand, you generally want to avoid things like tuna and mayo when trying to lose weight.

Can I eat tuna every day and lose weight?

In theory, it should be possible to eat tuna every day and lose weight.

However, due to the mercury content in tuna, it is generally not smart to consume this fish every single day.

Are tuna diets a good idea?

There are a variety of 3-day, 5-day, etc. tuna diets with very restrictive additional ingredients like only mainly eggs or something similar.

While you could theoretically lose a lot of weight on a tuna diet, these are generally not a good idea.

Part of this is the high mercury content of tuna which quickly adds up.

Additionally, restrictive diets like this are typically not sustainable and easily lead to nutrient deficiencies.

Will tuna help you lose weight

Is tuna or chicken better for weight loss?

Since chicken is another popular protein source, it can be helpful to know how it compares to tuna for weight loss.

First of all, 100 grams of ground chicken contain about 201 calories per 100 grams which is slightly more than tuna (2).

Additionally, ground chicken is slightly lower in protein with 27.1 grams per 100 grams.

Tuna is higher in many vitamins and minerals than chicken too.

In short, when it comes to the more standard nutrients, tuna is slightly better than chicken for weight loss.

At the same time, due to the mercury content, you likely want to eat chicken more often than tuna.

Chicken is still good for weight loss too.


Is tuna good for losing belly fat?

Tuna will not target this area specifically but it is still one of the best protein sources for losing belly fat.

Do keep in mind that this fish is high in mercury too. You don’t want to eat too much of it either.

Is canned tuna good for weight loss?

Even if the tuna is canned in oil, it is generally good for weight loss in terms of the most important nutrients.

You do want to limit your portions to some extent due to the mercury in tuna.

Is tuna and mayo good for a diet?

Tuna is generally weight loss friendly but the combination with may is typically not good for a diet.

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Matt Claes founded Weight Loss Made Practical to help people get in shape and stay there after losing 37 pounds and learning the best of the best about weight loss, health, and longevity for over 4 years. Over these years he has become an expert in nutrition, exercise, and other physical health aspects.