Eggs are part of the carnivore diet, are they not?  I’m on a keto diet and rely very much on eggs when Fridays come around.  Aren’t fish approved on the carnivore diet as well?  Fish is not considered childrens’ food exclusively.  Many cultures rely on fish as a main staple in their meals.  If one does not care for fish, maybe experimenting with different kinds would be of benefit.  A thick tuna steak tastes very much like a beef steak.  Good for the OP trying to improve his/her health through food!

No, eggs are not part of a carnivore diet, the word “carne” being translated in english as ‘meat” or “flesh”, as in sins of the flesh are carnal sins. Carne can be beef, lamb, pork, chicken, turkey, duck, but not fish and not eggs.

yes, and some cultures thrive on pasta, and working men can do a hard days work in the fields on bread, a few olives and wine.

I think a lot of our dietary problems are related to lack of or the wrong type of work. That goes for me too!

My husband fasts on Fridays from all food, drinks only teas. I like it because it means less work for me. 

No, eggs are not part of a carnivore diet, the word “carne” being translated in english as ‘meat” or “flesh”, as in sins of the flesh are carnal sins. Carne can be beef, lamb, pork, chicken, turkey, duck, but not fish and not eggs.

yes, and some cultures thrive on pasta, and working men can do a hard days work in the fields on bread, a few olives and wine.

I think a lot of our dietary problems are related to lack of or the wrong type of work. That goes for me too!

My husband fasts on Fridays from all food, drinks only teas. I like it because it means less work for me.

Ha, it's true, fast days have a lot of benefits including no food prep, no clean up, no waste, and it's cheap.  The carnivore diet has several variations and many of them include eggs.  Some carnivores eat red meat only.  Some eat any animal meat only.  Some eat any animal and their products only (eggs/dairy).  Some eat mostly carnivore but add a few keto or low carb options, but this is still considered carnivore.     

Eat fish on Friday- that's carnivore

Nup! That’s pescevore. Any here into pescetarianism? Just kidding. I like the sound of the word.

I'm considering the carnivore diet strictly for health reasons (severe allergies, fat loss, hormone balancing).  It would involve the cessation of consuming anything not of animal origin and primarily eating only ruminants (beef and sheep).  I would combine this with intermittent fasting.

Is anyone aware of any teaching against this?  Is there any harm in eating meat on Friday for health reasons as long as nobody was scandalized by it?

I found the carnivore diet very helpful for dealing with various health issues.  I first tried it out of desperation at a time when I was very sick and was surprised by how effective it was.  After this, I looked into the "nutrition science" behind standard dietary advice and discovered there is little foundation for most common beliefs on the subject.

I have found it possible to combine the carnivore diet with following traditional Catholic practices of fasting and abstinence.  One of the effects of eating this way is that one can go for longer periods of time without eating. One has a different experience of appetite and hunger. It changes how the body functions.  Once the body has adjusted (usually a week or two), there is little problem with doing water fasts on Fridays.  During Lent, one can follow partial abstinence rules by eating meat once a day.

So I don't think it is actually medically necessary to eat meat on Fridays.  On occasions when I have needed to eat on a Friday (e.g. illness, unusual physical exertion) I have had fish or eggs. In my experience, one can not use the carnivore diet to justify eating meat on Fridays and there is no good reason to give up this ancient discipline.