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How to Do the Tuna Diet

Mary Smith
By Mary Smith. Updated: January 16, 2017
How to Do the Tuna Diet

"Lose up to 5 kilos - that's 11 pounds - in 3 days": This is what the tuna diet claims to do. This is a quick way to slim down whilst also benefiting from the nutrients of this oily fish. It cuts down your calorie intake, which makes your metabolism work faster and thus burn more energy from your fat reserves. This will reduce fat in your body and cause a visible weight loss.

It should be noted that this diet is a method that is designed to detoxify your body and shed some extra kilos quickly. However, after the three days of this diet, you should continue to monitor your diet and choose healthy options, avoiding lots of high-fat foods. Failing to do so will see you gain all the weight you've lost, if not more.

Here at OneHowTo we'll tell you how to do the tuna diet so that you can start to shed those unwanted extra pounds.

You may also be interested in: How To Do The Sandwich Diet

Steps to follow:


The first thing to take into account is that the tuna diet is a very strict and low-calorie plan. Fewer calories are consumed than our body needs on a daily basis. In view of this, it should be followed for a maximum of 3 days to avoid any nutritional deficiencies or falling ill.

Tuna is an oily fish and, therefore, has a high amount of omega 3 fatty acids. This is a key nutrient to keep our body functioning properly and provide us with enough energy to face the day ahead. This diet does allow the consumption of other healthy foods, particularly fruits and vegetables. Of course, these are very nutritious and will help you feel well during the three days of the diet.

How to Do the Tuna Diet - Step 1

The reason that the tuna diet works is because this food (provided it is in its natural form, i.e. without oils) contains only 0.8% fat per 100 grams of fish. What's more, these fats are all unsaturated, colloquially known as "good fats". In this article you can find which foods contain healthy fats and understand what they are exactly.

As well as the above, tuna is a protein-rich food (28% of every 100 grams is protein). This helps improve bodily functions and form muscle tissue without adding more fat to the body. It is for this reason that this diet can function properly if what you want is lose weight fast.

How to Do the Tuna Diet - Step 2

For the tuna diet to work and for you to achieve your weight-loss goals, you will have to do the following:

Exercise frequently

It is best to do 30 minutes a day of exercise that combines cardiovascular workout with toning. If you cannot do so on a daily basis, go from 3 to 5 days per week to a gym and do at least 1 hour of training to burn excess calories and strengthen your body.

Here you can learn how to plan a cardio workout.

Drink 2 litres of water

It is important that you increase water consumption in your diet and drink at least 2 liters of water per day. This will help your body detox naturally, eliminating toxins and reducing fluid retention that causes swelling and cellulite.

Forbidden foods

During the 3 days of the diet of tuna you cannot eat any of the following:

  • Red meat
  • Canned or packaged products
  • Sweets (even diet)
  • Sauces
  • White (or refined) flour
  • Greasy food (salty snacks, junk, fried or breaded foods, etc.)

Vegetables and fruits - unlimited

That's right: tuna can be combined with any amount of fruits and vegetables. This ensures your body receives all of the essential nutrients for it to work properly. In addition, they will curb your appetite as they have a very high fiber content.

Eat 5 to 6 times a day

This point is also essential for this diet. Dividing your food into smaller portions will help reduce food cravings, curb your appetite and prevent you from getting very hungry before your main meals of the day.

How to Do the Tuna Diet - Step 3

We at OneHowTo have provided a sample menu from the tuna diet to give you an idea of how the meals are distributed. You'll also better understand the recipes you can prepare to shed those excess pounds. As an example, you can eat vegetables and fruits of your liking.


  • Option 1: 1 can natural tuna, fresh pineapple, coffee with skimmed milk
  • Option 2: 1 whole wheat toast with tuna, fresh orange juice, tea


  • Option 1: Seasonal fruit salad
  • Option 2: Non-fat yogurt


  • Option 1: 1 chicken breast, 1 baked potato with sautéed vegetables and fresh fruit
  • Option 2: 1 cup brown rice, 1 can green salad with tuna, non-fat yogurt

Afternoon Snack

  • Option 1: Fresh fruit
  • Option 2: 1 can natural tuna


  • Option 1: 1 can natural tuna, baked peppers
  • Option 2: 1 boiled egg, 1 can natural tuna, baked eggplant
How to Do the Tuna Diet - Step 4

You should know that a very popular variant of this tuna diet is the tuna and pineapple diet. This makes the most of the benefits of tuna as mentioned above along with those of pineapple, a perfect fruit to help us lose weight. Pineapple has diuretic and detoxifying properties, and is also a negative calorie food - that is, it requires more calories to digest it than it gives.

As before, this diet should only be followed for 3 days maximum. The restricted foods are exactly the same as those we have mentioned above. The main difference between the two methods is that the latter allows the consumption of one fruit only - pineapple. The reason is that this fruit is rich in water, fiber and has a high satiating power which, combined with tuna, will get you into top shape in no time.

How to Do the Tuna Diet - Step 5

Do you have any tips on how to do the tuna diet? Tell us in the comments section!

If you want to read similar articles to How to Do the Tuna Diet, we recommend you visit our Weight & image category.

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