Why is Seafood Allowed on Fridays in Lent? St Thomas Aquinas Provides the Theological Answer

So on Fridays during Lent, Catholics may eat shrimp, sea-bass, and lobster, but not steak, spam, chicken, or hot dogs. Why?

Is this distinction completely arbitrary or is there a theological, or even biblical, argument for this rule?

taylor marshall with rainbow trout fly fishing

Taylor with a Rainbow Trout in Montana.

Ray, a reader of this blog, gets to the heart of the question:

We are encouraged [in Belize] to eat fish or seafood on Fridays. The odd thing is that seafood is more expensive than say chicken, so I wonder whether it is really sensible to have fish or seafood which would really be even more luxurious fare than the normal chicken or beef. Shouldn’t the spirit of abstinence necessitate that any sort of luxury food be given up? Also, why would warm-blooded creatures be restricted in the first place?

Could you perhaps give an explanation of the restrictions on the blog? I know you are well versed in this area and expect, should you be able to give one, a response that will be comprehensive.

With grateful appreciation,


This is a great question, Ray. Especially considering the cost of seafood as compared to lunch meats.

Saint Thomas Aquinas gives two theological reasons for the prohibition against meat in Lent.

1) First, Christ offered his flesh for our us on the wood of the cross. Since Christ gave us his flesh, we also give up flesh meat.

2) Saint Thomas’ second reason for “no meat” requires a bit more explanation. Here is Thomas in his own words:

Fasting was instituted by the Church in order to bridle the concupiscences of the flesh, which regard pleasures of touch in connection with food and sex. Wherefore the Church forbade those who fast to partake of those foods which both afford most pleasure to the palate, and besides are a very great incentive to lust. 

Such are the flesh of animals that take their rest on the earth, and of those that breathe the air and their products, such as milk from those that walk on the earth, and eggs from birds. For, since such like animals are more like man in body, they afford greater pleasure as food, and greater nourishment to the human body, so that from their consumption there results a greater surplus available for seminal matter, which when abundant becomes a great incentive to lust. Hence the Church has bidden those who fast to abstain especially from these foods.

So hot blooded animal foods generally provide more pleasure than cold blooded animal foods. Saint Thomas associates pleasure from food to pleasure from sex.

Our food intake, teaches Thomas, effects our libido.

I bet you’re weren’t expecting that answer! And there is science to back it up. Higher testosterone leads to a higher libido. It’s scientific fact.

Guys, do you want to increase your testosterone, eat more red meat and fatty meats. Same goes for women. Harvard Medical School found that women can increase their fertility responsiveness by increasing protein intake and switching to full-fat milk.

Want to decrease your testosterone? Eat more salad, soy, sugar, simple carbs, veggies, and lean fish. Cut out red meat and dairy.

Remember that Thomas Aquinas sat under the teaching of Albert the Great – Europe’s premier biologist. It may sound medieval, but they were on to something back then. They knew that human fertility (and sexual concupiscence) was related to the consumption of animal products.

Is it any accident that the terms like:

  1. red-blooded
  2. hot-blooded
  3. stud
  4. bull
  5. red meat
  6. muscular
  7. meaty
  8. braun (originally meaning “meat” or “roast”)

are related to fertility and virility.

But what about lobster or oysters?

Writing in the 13th century, Thomas recognized this problem: “Further, some fish are as delectable to eat as the flesh of certain animals. Now “concupiscence is desire of the delectable,” as stated above (I-II, 30, 1).”

Saint Thomas writes that the Church rules regarding this in general and that eating flesh meat is generally more desirable than eating fish. If you doubt this, count the number of burger restaurants, steak houses, and fried chicken restaurants and compare that number to the number of Long John Silver franchises.

Of course, lobster is much better than Long John Silvers, isn’t it? It’s probably a good rule of thumb to avoid lobster or crab in the spirit of penance. However, for me, I’d much rather have a steak or burger than lobster.

Fancy Wine?

It’s very similar to wine. The Church doesn’t forbid drinking $100 bottles of wine during Lent, but it’s contrary to the spirit of Lent. The Church’s general rules of Lent are the bare minimum. The heartfelt sacrifice of love by which we offer little hidden penances (like eating the salad and not the lobster on Friday) to Christ bring joy to His heart and grace to our souls. Most people don’t regularly eat lobster anyway. Most people do, however, eat meat regularly, and the Church thinks that we should make more sacrifice in this regard on Fridays.

And who knows, maybe your decreased consumption of hamburgers and steak will keep you on the straight and narrow!

Question: Question: For you personally, is Lenten fasting and abstinence more about the lack of pleasure or the discipline? Can these even be distinguished? For me, it’s about the discipline: making my will conform to a standard and telling my appetites “no!” What about you? You can leave a comment by clicking here.

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  • Kathleen

    Since I’m well past the age for fasting … this applies only to abstinence.

    Lack of pleasure or discipline? Definitely not lack of pleasure. I grew up in the days of meatless Fridays. Meatless doesn’t mean you have to eat fish. There are lots of delicious vegetarian meals.

    Abstinence is a discipline for me – having to think about it – pay attention and plan ahead.

  • MarytheDefender

    In my country, the Philippines, it is quite the opposite. Fish is the poor man’s food. Meat is for the rich! Especially in rural communities, a freshly cooked chicken is a special treat for fiestas and visitors. Of course it also depends on the kind of fish. Supermarkets have imported salmon and that certainly isnt that penitential.

    • The Ubiquitous

      This was also the case in the Apostles’ time.

  • Max P Fritzel

    This is a very interesting discussion, but a related question came up during an event I attended this weekend. Does the church frown on ‘weddings during lent’?

    • Sonia

      When I was young, I think weddings were not scheduled during Lent, but since then I have been to Catholic weddings during Lent. Has there been a change? If so, what is the reasoning behind it?
      If a couple is married during Lent, many, if not all, of their anniversaries will be in Lent also, which is problematic.

  • Alexis

    I happen to love seafood more than meat. When we go out I always order some type of seafood. (I am not fond of lobster). So, what do I do?

    • Glenn

      My wife and I give up going out to dinner for all of Lent. If that is not an option, then order seafood to maintain the Friday abstinence.

    • Roger

      maybe abstain from all sorts of meat, including fish, for Lent. We are required to fast from meat on Fridays, but we are not limited to only doing this. That is just the bare minimum. So if you wanted to make a further gift of yourself to our Lord, that might be a way for you to do so.

    • Mainman12

      I do to. For my wife does not like fish and so I rarely get it at home.

  • Nola

    “Such are the flesh of animals that take their rest on the earth, and of those that breathe the air and their products, such as milk from those that walk on the earth, and eggs from birds.” – WHOA! I’m a cradle Catholic and we abstain on all Fridays of the year, not just during Lent, but we also have milk & eggs on Fridays. Is that breaking abstinence? Thanks. BTW I do remember the great joy with which we greeted Oyster Po’boys (sandwiches) on Fridays when I was growing up in New Orleans, so I guess that wasn’t really in the spirit of fasting either.

    • The Ubiquitous

      Not according to the Church’s law. However, as recently as the ’60s, the mandatory discipline was much stricter. You may keep this as a voluntary discipline, of course.

  • Marilyn

    I often get a kick out of the discussions of Lenten fasting and abstaining from meat. It always seems like such a concern to so many. I have been a vegetarian for 40 years eating neither meat or seafood of any kind and it really is not that difficult. I decided to give it up one day (due to my love of animals) and have never gone back. As for Lenten sacrifices, I think it is about both pleasure and discipline in giving up that which you like the most. It can only be significant as penance if it takes true effort and sacrifice.

  • MomLovesLacey

    For me, Lent is a season of less – less food entirely and certainly no pleasure foods, less money spent on anything unnecessary, less activities…just less. Each of us has different taste buds so pleasure foods would mean different things – for me peanut butter is an amazing pleasure food that I deny for Lent. Of course, on Sundays we are supposed to indulge in some pleasure food but I still omit deserts even on Sundays during Lent. My teen is much more a rule person – she says, “no meat” means no meat and she can eat everything else. In fact, family is taking her out for a dinner on the town to celebrate a big accomplishment of hers and she wrote to them: “My mom is really strict – when people ask her what she gave up for Lent she says, ‘pleasure'”.

    Honestly, I’m not that strict but I do believe in not giving myself excuses. If I’m hungry the veggies will be just as filling as a steak. During Lent I add more service work, much more prayer time and subtract all pleasure foods (zero sugar!) and certainly would not go out to dinner – at all. In fact, this week I have to travel but I’m blessed to be going with a friend of great example. Yesterday, we were talking about what we could do the night at the motel because we aren’t willing to go to the giant outlet mall close by as unnecessary shopping is out for Lent (pleasure again), and we wouldn’t go to the casino anyway even though one is close to where we are staying, and we can’t even go out and enjoy a meal at the restaurant so we decided to bring the laptop and watch the Passion of the Christ – which is an annual Lenten activity these past many years but we will just do it earlier than our normal Holy Saturday viewing.

    It may sound excessive but I started with just “white-knuckling” my way away from only candy! (And come Easter I ate it again). Then came TV, another year was coffee too, last year was the internet, and I’m happy to say I’ve never gone back to any of these “addictions” in big ways again. Once I did without them, they no longer “owned” me – I was truly detached from them. Now, food sacrifices are mostly too easy for me, so this Lent I’m going for silence – I usually have Christian music on at *all* times but this year my home is quiet (this has been my hardest Lent yet). Also, all these sacrifices are tied to other people, the food I don’t eat gets paid into my rice bowl, the prayers I increase are nearly all intercessory for others (except the copious prayers of gratitude), and the money I won’t be spending on a restaurant will be put into the rice bowl as well – I will simply be bringing a bowl of beans for dinner in the motel. The silence gives me more time to listen for the Lord (that is when the enemy isn’t telling me He doesn’t care if I listen to music :-).

    For me, Lent is a season of self-denial for the purpose of sensitizing me to just how much I spoil myself the rest of the year. My goal is to do that less by really denying myself for all of Lent. I’ve only been Catholic for my adult life (having been raised in an atheist home) but I’m happy to report that each and every Lent has left me a better Christian – that’s the real reason I do this :-). Someday, my teen will understand but right now she just follows the requirements and thinks I’m strange :-).

    • mike banks

      I would like an in-depth tutorial on fasting. In my mind, fasting means not eating and I suspect that is the classical understanding as well. So, what are we looking for in our fasting – What do the spiritual masters have to say about it? For this subject to devolve into juridical prescriptions about half-meals and poultry by-products would not be helpful. Just some insight into straight fasting. Thanks, m

    • Sherelle

      Wow, I think you’re my clone, especially regarding peanut butter! I also focus on less. As a family, no fast food, no desserts, cakes, biscuits. I’m always amazed how often I stop myself putting groceries in the trolley, that aren’t “needed” during Lent. Little treats build up over the year (especially over Christmas), that are culled in this season. The Church is wise giving us this time to get back to basics, and focus more on God. It’s interesting how the little ones (3-4 year olds) keep persisting in asking for desserts at the start, but by Easter no-one expects it anymore! Personally apart from eating smaller, I also try to be more faithful to my daily duties without being distracted too much! Like St Therese, I love reading, so putting down a book, or severely limiting Internet, to focus on home-keeping takes discipline. With eight children at home there is always more to do. Cheers & God bless

    • Albie in Angelus

      Wow…your post embodied everything I try to do AND THEN SOME!!!!!!! I would LOVE to read your conversion story! Glory to God for what He has done in your life! You are so on target……what a delight to learn that you are a convert! God is so good!

  • David

    Definitely discipline. There are many desirable fish dishes but it is the discipline of foregoing meat that raises our awareness of sacrifice.

  • Darren

    To add to David’s thought, by viewing a fast as disciplining the will it makes it more manly to to do.

  • Joe

    Would appreciate references for your ideas that red meats increase testosterone. Also it should be ”

    Our food intake, teaches Thomas, affects our libido.”, not ”

    Our food intake, teaches Thomas, effects our libido.”. I caught that and I’m an engineer. Just sayin…

  • Victor

    Doctor Marshall, I was wondering if we are allowed to eat all species of fish on Fridays?
    I’ve learned that some fish species are older than one hundred million years old so does that make a difference? 🙂
    Happy Saint Patrick Day.

  • Sonia

    People used to fast from eggs and dairy products during Lent, but now we don’t. What brought about the change?

  • Fr Ben

    A lot of the explanations I have heard about this don’t totally connect. In much of the ancient world, as it is in the poorer parts of the world today, meat was a luxury and only the super rich could afford to eat meat everyday. However, I think that this practice has its roots in Jewish sensibilities. In Acts 14, the Apostles declare that they will only impose these obligations on the newly converted Gentile churches: You are to abstain from food sacrificed to idols, from blood, from the meat of strangled animals and from sexual immorality. All the animals that we abstain from on Fridays are animals that need to be bled out when they are killed; there is no need to bleed out fish or seafood. I think that this sensitivity against shedding blood on the day when Jesus shed His blood, or eating animals that have (red) blood in them has hung on in the form of Friday abstinence from meat.

    • Julia B

      The connection of Lenten abstinance with “meat” animals that are bled out by the Jews makes a lot of sense. My sister who is a Jewish convert and my Jewish sister-in-law are always very careful ordering steak. I’ve had some kosher steak and it is quite tasteless to this lover of a juicy, medium-rare T-bone I think Aquinas and lots of other church writers of his time were trying to figure out the reason for things in retrospect. Kind of like the Golden Legend’s fanciful entymoligies of long-dead saints’ names.

  • JDJL

    “Some fish are as delectable…” I love this question in the Summa; it always makes me think of Thomas on his deathbed at Fossanova, asking for fresh herring.

  • Julia B

    Like Kathleen, I’m also past the age for fasting. I recall learning that at the time of Aquinas, most people performed heavy labor – both women and men. So only the wealthy and town people like scholars were not excused – so the rules are mainly aimed at the people whose lives were mostly sedentary. Peasants rarely ate meat anyway. Much of the time they barely got enough to eat in non-Lenten times. If they did happen to get a piece of meat it was stretched out over a week – stew, soup, bits with vegetables, broth, etc.

  • Julia B

    As a child we had lots of grilled cheese and tomato soup on Fridays. Sometimes we had fried corn meal mush with syrup. To this day, I can’t bear to look at fish sticks. LOL

    • conmargar

      “Can’t bear to look at fish sticks” My dad fished and we almost always had fish on Friday’s. Excess catch was frozen for winter, along with ice fishing. Once we were at my aunt’s house on Friday (She lived 2 1/2 hours away and the highway had not yet been built so we weren’t there often) She was having fish sticks. Wow! I thought they were great. My dad didn’t allow food like that in the house, so I was in heaven with the fish sticks. It is interesting how affected we are by our experiences. Today we usually have items that are closer to vegetarian – roasted tomato pasta, bean tostadas and the like.

  • BE

    It is absolute nonsense that certain foods (soy, et al) diminish sexual feelings.

    • Deacon Steve Miller

      Correct BE. MT runs this from Aquinas every Lent. Not everything the Angelic Doctor uttered or wrote was accurate. Fasting is Scriptural, and an important spiritual exercise. The Church has the keys and needs to revisit the current medieval practice. What we do today is based on ill logic. In fact, many parishes promote the opposite spiritual exercise w/ elaborate fish fries to raise money doling out monster fried fish, fries, pizza, etc. Fasting should be a proper sacrifice involving true self denial AND lead us to almsgiving for the poor.

    • Take it up w Harvard Medical and Thomas Aquinas. 😉

  • El_Tigre_Loco

    I think that everyone is missing one of the important aspects of Friday fasting: Thinking about God. The more we think about Him, the more likely we will do what He wants. “Thy will be done.”

  • Tony

    I grew up without meat on Fridays. But I find it a bigger sacrifice to forego a drink Friday nights – something I might look forward to, to help wind down after a demanding week.

  • JuanOskar JayMaynes

    I live in the Sonoran Desert so it’s much easier to find fowl and cattle than fish.

  • Mainman12

    By age I am beyond the age for fasting. But because of the good health with which I am blessed I am happy to continue to fast. As for abstinence for me it is not with regard to pleasure but more to discipline but even more to this making me aware multiple time of day of my Lord, of being reminded of him and all he has and is doing for me… for he comes to mind the many times a day I have a thought of what I have given up. I’m a convert of over 14 years. Back in the late 50s when I was in a public high school I loved the Friday’s of abstinence from meet about which my Catholic friends all seemed to complain. I loved those Fridays because it meant the school cafeteria would always have fish, which I loved, on the menu.

  • aquinasadmirer

    I heard an explanation by a priest on a Catholic radio program that in Mexico poultry is okay during lent, because when the Latin “carne” is translated into Spanish, it has the connotation that it only applies to mammals. For example, carne asada is not poultry; it’s either pork or beef.

    Does this sound correct? I’m unsure.


  • TJ Frohlick

    Total silliness. Eat fish twice a week and not on Friday. This is the kind of false teaching that chases away good people. tjf

  • Riddle of the Sages

    To evolve our senses, I believe it to be logical in substaning from the death of any species, not simply because anyone says so but because it is ethical.

  • veggie

    Go vegetarian for all of Lent and then make it a lifestyle change. Not quite as restrictive as honey and locusts.

  • Jim Carroll

    A few years back, on the Catholic Answers Forum, this question came up. A key point was the Latin (not Spanish) definition of “carne”, or “meat”, which includes poultry. It does NOT include seafood of any sort. (BTW, the USCCB recently ruled that alligator counts as not-meat for the purpose of abstinence.) The whole discussion turned silly when someone asked if that meant that we could eat mer-folk (mermaids and mermen). The consensus was that only the tail portion was acceptable, but that trolls and unicorns were not. (Which worked for me — troll tastes too strong for me unless you soak it for a couple of days in beer.)

  • LH

    Wait a minute…no eggs, too?

    • Lisa Ann Homic

      I’ve read the different traditions. Some cultures gave up eggs and dairy. Eggs are not flesh and allowed in U.S. (conference of bishops website). My blood sugar can drop fast and I am low carb because it is healthier. I am very glad to have eggs otherwise I would get sick and foggy headed.

  • Albie in Angelus

    We live in rural Kansas….we NEVER get seafood. We have a local restaurant that annually has a Lenten seafood all you can eat buffet pig fest on Friday nights. We have begged them to extend the special to one Friday after Lent so that our family could partake, but to no avail……sigh. Your words “the heartfelt sacrifice of love by which we offer little hidden penances to Christ bring joy to His heart and grace to our souls” was extremely heartening. Thank you. I also thank you for the excellent exegesis on Aquinas……AMDG!!!!!.

  • Theresa M Shotwell

    I have a friend (a lapsed Catholic) who insists that it was a fishing guild that pressed for this no meat fast. I know there is a better explanation. Do you know where she might have gotten this idea. She said she learned it at our Catholic high school in the 1960’s. (go figure!).

  • Rudy Spongelli

    I think Aquinas overanalyzed this to the point where most people end up following a ritual they don’t quite understand, and there is little or no spiritual growth.

  • Teresa

    I say discipline. Another informative, funny, interesting and fact based way to present important concepts-I learned so much from reading this article. Thank you!!!

  • Anna

    Does mahi mahi (dolphin) count as fish? It lives in the sea but is a mammal…

    • haha