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.

Would you like to get Dr. Marshall’s latest book Thomas Aquinas in 50 Pages for FREE? Please click here to receive it.

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