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Do Fish Oil Supplements Break a Fast?

Isaac Robertson
Published by Isaac Robertson
Fact checked by Donald Christman, BHSc FACT CHECKED
Last updated: March 20, 2023
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There’s been so much debate among experts around what breaks a fast and what’s safe to consume while fasting.

So, many people come to me confused and in need of advice.

That’s why I’ve spent a few months thoroughly exploring how different foods, drinks, and supplements without added sugar impact intermittent fasting and whether they can assist in achieving your workout goals.

If you’re like many of my clients wondering whether fish oil consumption can increase your sugar levels and break a fast, you’ve come to the right place for an answer to your question.

Fasten your seatbelts.

Quick Summary

  • Fish oil doesn't break fast as it contains pure fats with no digestible proteins or carbs, and very few calories.
  • The benefits of fish oil include fighting inflammation, lowering the risk of developing chronic diseases, and preventing dementia.
  • Fish oil is best taken with food, and specifically meals rich in fats.

Will Fish Oil Break a Fast and Raise Blood Sugar Levels?

Fish oil supplementation in a regular average dose of 1-2 grams per day probably won’t break your fast because it contains pure fats with no digestible carbs or proteins and very few calories (around 10 calories per gram and approximately 45 calories in one teaspoon).

Fish oil in a small plate

If you’re fasting for: 

  • Overall health
  • Longevity
  • Weight loss
  • Hunger or junk food cravings suppression
  • Metabolism increase to aid the fat-burning process
  • Turn on autophagy
  • Fight insulin resistance

a few fish oil pills or drops won’t make any significant difference as they won’t elicit an insulin response, influence your blood glucose chart, or significantly impair autophagy.


Fish oil will still stimulate your gut and disturb your gut rest.

Although these healthy polyunsaturated fatty acids don’t trigger insulin release that breaks a fast, and the minimal calories almost don’t affect how your body will break down its own fat stores, you still have to digest and absorb fish oil.

So, if you’re worried that anything above zero calories will break your fast, here are some helpful tips on how to consume it while intermittent fasting.

How to Take Fish Oil When Fasting

Spilled fish oil supplement

Technically, you can take fish oil at the time that may work best for you, but it’s best during your eating window.


A meal that contains fats will enhance absorption due to the higher fat-digesting enzyme potential in your body. [1]

Plus, you’re less likely to experience any gastrointestinal and other side effects.

To avoid problems with digestion, you may also split your daily intake into two doses and take each with a different meal. Also be careful when choosing your fish oil supplement.

“Without a proper meal, especially a high-fat meal, the natural digestive processes in the body are slower and less effective. If an omega-3 supplement is usually taken in the morning without food, less will be incorporated into cell membranes, potentially not providing the expected benefits. Meal-skipping, especially breakfast, therefore means consumers might not be getting sufficient omega-3 to where it’s needed, no matter how strong or potent the supplement claims to be.”

- Per-Olof Larsson, Global Head of Scientific Affairs at BASF

The Best Sources of Omega-3s to Take After Fasting

When you break the fast, your body frequently faces significantly increased inflammatory response and inadequate ability to get all the necessary nutrients. [2]

Lower nutrients will affect protein synthesis, meaning you cannot build or preserve as much muscle.

The best EPA and DHA omega-3 sources to introduce a few hours after you break your fast to decrease inflammatory cytokines and promote muscle protein synthesis should be natural and as potent and lean as possible. [3] [4]

The perfect examples include sockeye salmon, sea bass, shrimp, mackerel, sardines, grass-fed beef, or chicken supplemented by top-quality fish, calamari, or algae oil.

Fish Oil Benefits

Your health may benefit from omega-3s from fish oil in numerous ways, including: 

  • Lowered risk of age-related macular degeneration
  • Fighting inflammation
  • Lowered risk of chronic diseases such as stroke, heart disease, even cancer
  • Reduced symptoms of rheumatoid arthritis
  • Decreased triglyceride levels
  • Preventing dementia and improving cognitive function
  • Inducing autophagy

Are There Side Effects to Taking Fish Oil?

The possible side effects to taking fish oil are typically mild and might include: 

Fish oil supplements on a table
  • Bad-smelling breath and sweat
  • Unpleasant taste
  • Headache
  • Lower blood pressure
  • Increased risk of bleeding (adverse interaction with blood clotting medication)
  • Diarrhea
  • Nausea
  • Heartburn

You are going to minimize the side effects by making sure your fish oil has not expired.


Can I Take Fish Oil on an Empty Stomach?

Technically, you can take fish oil on an empty stomach, but it’ll probably get less absorbed.

What Is the Best Way to Absorb Fish Oil?

The best way to absorb fish oil is to take it with food, specifically a meal rich in fats such as bacon and eggs. In addition, studies have shown it’ll maximize its effectiveness and reduce potential side effects like indigestion, acid reflux, nausea, diarrhea, and belching. [5] [6] [7]

Does Fish Oil Help Lose Belly Fat?

As research has found, fish oil supplements can help you burn extra belly fat faster, reduce waist circumference, and improve your body composition if combined with a restricted weight-loss diet and regular aerobic exercise. [8] [9]

Is Omega-3 Fish Oil Keto and Paleo-Friendly?

In general, supplements like fish oil are Keto and Paleo-friendly. You can safely take pure omega-3s as they won’t kick you out of ketosis. Just make sure you go for great products from reputable brands that use high-quality wild instead of farmed fish.

Summary: Does Taking Fish Oil Break a Fast?

Taking fish oil in low doses doesn’t break a fast.

Just be aware that it’ll impact your gut rest even though it doesn’t inhibit autophagy. Plus, it gets better absorbed when taken with food.

In summary, it’s up to you to decide whether you’ll take it or not and how much. It depends on your reasons for fasting, how long you’re fasting, and how strictly you stick to your fasting program.

Let us know what you’ve decided and how it works for you.


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