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Why Is Fish Good for You? Top Reasons to Eat More Fish on Keto

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  Published on March 8th, 2022
  Reading time: 4 minutes
  Last modified July 24th, 2023
Salmon and other fish containing healthy omega-3 fats

Fatty fish is packed with nutrients and omega-3 fatty acids to fuel your cells! From smoked salmon to crisp-skinned mackerel, flaky tuna, and flavorful little anchovies, most of us can agree fish is delicious as well as nutritious. Let’s discuss the reasons why fish is good for you and how to add more to your ketogenic diet.

Why Is Fish Good for You?

As you’ll see below, fish is beneficial to many parts of the body and studies suggest fish has a positive and preventative effect on many health conditions. Many of these benefits seem to be related to the high levels of healthy dietary fats and vitamin D found in fish, though fish contain other nutrients as well, such as B vitamins, selenium, and iodine.

1. Brain Health

Observational studies reveal those who consume more fish have slower rates of mental decline. Those who eat fish weekly also have more gray matter in the parts of the brain that regulate memory and emotions. Grey matter refers to major functional brain tissue. [1] [2]

2. Depression

Depression is a mental condition involving low mood, overarching sadness, reduced energy, and a loss of interest in life and activities that used to be enjoyable.

Studies show people who frequently eat fish are less likely to experience depression. Mounting controlled trials show omega-3 fatty acids can improve depression and drastically increase the effectiveness of antidepressant medications, and fish are a major source of omega-3. [3] [4]

The omega-3 fatty acids in fish might help other mental conditions as well, such as bipolar disorder. [5]

3. Reduced Risk of Heart Attack and Stroke

Studies show that people who regularly eat heart-healthy fish have a reduced risk of strokes, heart attacks, and heart disease fatality. [6] [7]

One impressively large study of 40,000 men in the United States concluded that those who frequently consumed one or more servings of fish weekly had a 15% lower risk of cardiovascular disease. Fatty fish like mackerel are especially beneficial because they’re loaded with omega-3s! [8]

4. Dietary Source of Vitamin D

A shocking 41.6% of the United States population is low or deficient in the fat-soluble vitamin D. [9]

Vitamin D acts like a steroid hormone in your body that facilitates normal immune system functioning. Low levels of vitamin D have been tied to various respiratory diseases and viral illnesses.

Fish and fish products like cod liver oil are some of the best dietary sources of vitamin D, with tasty fish like herring and salmon in the lead. Smoked salmon, anyone? [10]

If you don’t eat fatty fish regularly or get much sunshine, you might consider taking a vitamin D supplement.

5. Protecting Vision and Preventing Degeneration

Evidence suggests fish and omega-3 fatty acids could protect against age-related macular degeneration (AMD)—a leading cause of blindness and vision loss that predominantly affects older adults. [11]

For example, one study showed regular fish intake was associated with a 42% reduced risk of AMD in women. [12]

The lower risk of autoimmune disease could be due to the omega-3 fatty acids and vitamin D found in fish and fish oils.

6. Reduced Risk of Autoimmune Disease

Autoimmune diseases happen when your immune system mistakenly attacks and destroys healthy tissues in your body. Autoimmune diseases often involve inflammation, pain, and other symptoms that can diminish quality of life. Studies have associated fish oil or omega-3 intake with a lower risk of autoimmune diabetes in adults and type 1 diabetes in children. [13]

Fish oil has omega-3 fatty acids

7. Better Sleep

If you’re not sleeping properly, it can throw everything off balance and trigger a domino effect of health issues. Sleep is critical to your body’s ability to rest and restore so you feel energized the next day. Vitamin D deficiency could be one of the obstacles between you and a good night’s sleep! [14]

For example, a 6-month study examined 95 middle-aged men who ate a meal with salmon three times weekly. The results were improved sleep and daily functioning. Researchers believe this could be due to the vitamin D content. [15]

8. Crucial Nutrients for Development and Growth

It’s often recommended that pregnant and breastfeeding women eat plenty of omega-3 fatty acids. Some doctors suggest supplementation. [16]

Omega-3 fatty acids play a crucial role in fetal growth and development, particularly for the brain and eyes. [17]

Keep in mind that some fish are higher in mercury, which has been associated with brain development problems in babies. A good way to remember which fish are safest is to use the word SMASH: salmon, mackerel, anchovies, sardines, and herring. These are some of the fish lowest in mercury and highest in healthy fats. Read our detailed article for more info on the problems with mercury in fish.

Pregnant women should consume low-mercury fish like trout and salmon, and they shouldn’t exceed 12 ounces (340 grams) per week. It’s also best for pregnant women to avoid uncooked fish due to the possibility of ingesting microorganisms that could harm the developing baby.

Adding Fish to Your Keto Diet

Healthy and keto baked cod

If you aren’t already eating it, fish is a delicious, nutrient-rich, and easy-to-prepare food that isn’t hard to add to your ketogenic diet. Try this 15-minute halibut and zoodles recipe, this baked cod with lemon butter, or a Dijon-mayo salmon dinner!

Among the many benefits and reasons to eat more fish are:

  • Reduced risk of heart disease, heart attacks, and stroke
  • Reduced risk of depression
  • Lower risk of autoimmune diseases
  • Crucial for fetal growth and development
  • Improved brain health
  • Dietary source of vitamin D
  • Preventing age-related macular degeneration (AMD)
  • Better sleep

Are you eating fish on keto? Share your favorite ‘fishful’ recipes and dishes with the keto community!

Steph Green is a content writer specializing in and passionate about healthcare, wellness, and nutrition. Steph has worked with marketing agencies, written medical books for doctors like ‘Untangling the Web of Dysfunction,’ and her poetry book ‘Words that Might Mean Something.’ In 2016, after four years of struggling with her own health problems and painful autoimmune disease, Steph developed a life-changing and extensive knowledge of keto, nutrition, and natural medicine. She continues on her healing journey and enjoys helping others along the way.



Morris, M. C., Evans, D. A., Tangney, C. C., Bienias, J. L., & Wilson, R. S. (2005). Fish consumption and cognitive decline with age in a large community study. Arch Neurol, 62(12), 1849-53. DOI: 10.1001/archneur.62.12.noc50161


Raji, C. A., Erickson, K. I., Lopez, O. L., Kuller, L. H., Gach, H. M., Thompson, P. M., Riverol, M., & Becker, J. T. (2014). Regular fish consumption and age-related brain gray matter loss. Am J Prev Med, 47(4), 444-51. DOI: 10.1016/j.amepre.2014.05.037


Lin, P-Y., & Su, K-P. (2007). A meta-analytic review of double-blind, placebo-controlled trials of antidepressant efficacy of omega-3 fatty acids. J Clin Psychiatry, 68(7), 1056-61. DOI: 10.4088/jcp.v68n0712


Grosso, G., Galvano, F., Marventano, S., Malaguarnera, M., Bucolo, C., Drago, F., & Caraci, F. (2014). Omega-3 fatty acids and depression: Scientific evidence and biological mechanisms. Oxid Med Cell Longev, DOI: 10.1155/2014/313570


Sarris, J., Mischoulon, D., & Schweitzer, I. (2012). Omega-3 for bipolar disorder: Meta-analyses of use in mania and bipolar depression. J Clin Psychiatry, 73(1), 81-6. DOI: 10.4088/JCP.10r06710


Djousse, L., Akinkuoulie, A. O., Wu, J. H. Y., Ding, E. L., & Gaziano, J. M. (2012). Fish consumption, omega-3 fatty acids, and risk of heart failure: A meta-analysis. Clin Nutr, 31(6), 846-53. DOI: 10.1016/j.clnu.2012.05.010


Zheng, J., Huang, T., Yu, Y., Hu, X., Yang, B., & Li, D. (2012). Fish consumption and CHD mortality: An updated meta-analysis of seventeen cohort studies. Public Health Nutr, 15(4), 725-37. DOI: 10.1017/S1368980011002254


Virtanen, J. K., Mozaffarian, D., Chiuve, S. E., & Rimm, E. B. (2008). Fish consumption and risk of major chronic disease in men. American Journal of Clinical Nutrition, 88(6), 1618-25. DOI: 10.3945/ajcn.2007.25816


Forrest, K. Y. Z., & Stuhldreher, W. L. (2011). Prevalence and correlates of vitamin D deficiency in US adults. Nutr Res, 31(1), 48-54. DOI: 10.1016/j.nutres.2010.12.001


Malesa-Ciecwierz, M., & Usydus, Z. (2015). Vitamin D: Can fish food-based solutions be used for reduction of vitamin D deficiency in Poland? Nutrition, DOI: 10.1016/j.nut.2014.07.003


Lim, L. S., Mitchell, P., Seddon, J. M., Holz, F. G., & Wong, T. Y. (2012). Age-related macular degeneration. Lancet, DOI: 10.1016/S0140-6736(12)60282-7


Christen, W. G., Schaumberg, D. A., Glynn, R. J., & Buring, J. E. (2011). Dietary ω-3 fatty acid and fish intake and incident age-related macular degeneration in women. Arch Ophthalmol, 129(7), 921-929. DOI: 10.1001/archophthalmol.2011.34


Stene, L. C., Joner, G., & Norwegian Childhood Diabetes Study Group. (2003). Use of cod liver oil during the first year of life is associated with lower risk of childhood-onset type 1 diabetes: A large, population-based, case-control study. American Journal of Clinical Nutrition, DOI: 10.1093/ajcn/78.6.1128


Gominak, S. C., & Stumpf, W. E. (2012). The world epidemic of sleep disorders is linked to vitamin D deficiency. Med Hypotheses, 79(2), 132-5. DOI: 10.1016/j.mehy.2012.03.031


Hansen, A. L., Dahl, L., Olson, G., Thornton, D., Graff, I. E., Froyland, L., Thayer, J. F., & Pallesen, S. (2014). Fish consumption, sleep, daily functioning, and heart rate variability. J Clin Sleep Med, 10(5), 567-575. DOI: 10.5664/jcsm.3714


Koletzko, B., Lien, E., Agostoni, C., Bohles, H., Campoy, C., Cetin, I…World Association of Perinatal Medicine Dietary Guidelines Working Group. (2008). The roles of long-chain polyunsaturated fatty acids in pregnancy, lactation, and infancy: Review of current knowledge and consensus recommendations. J Perinat Med, 36(1), 5-14. DOI: 10.1515/JPM.2008.001

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