Catholic fasting rules prohibited meat on certain days. Fridays, Lent, Advent, Ember Days. By medieval period, this meant avoiding meat 100-150 days per year.
— Sama Hoole (@SamaHoole) January 5, 2026
The monks noticed a problem: fasting was making them weaker. Hard to copy manuscripts when you're malnourished. Hard to… pic.twitter.com/h3zjAsoUQ1
Catholic fasting rules prohibited meat on certain days. Fridays, Lent, Advent, Ember Days. By medieval period, this meant avoiding meat 100-150 days per year. The monks noticed a problem: fasting was making them weaker. Hard to copy manuscripts when you're malnourished. Hard to farm when you've lost muscle mass. The work still needed doing. The solution was theological creativity. Meat was prohibited. But were eggs meat? They come from chickens, which are animals. After lengthy debate, theologians concluded eggs were "liquid flesh" and therefore not technically meat. Dairy presented similar questions. Milk comes from animals. Is it meat? More debate. Ultimate conclusion: dairy is "white meat" which is different from "red meat" so it's allowed during fasts. Butter was debated extensively. It's made from cream, which is milk, which comes from cows. But it's processed. Is it still "meat"? The final ruling: butter is permissible during fasts in moderation. The monks interpreted "moderation" generously. Medieval monastic dietary records survive. During Lent, when meat was completely forbidden, the monks consumed: - 4-6 eggs per person daily - Unlimited butter on bread - Cheese with every meal - Cream in soups and drinks - Fish (explicitly allowed) Their caloric intake during "fasting" was 2,500-3,000 calories daily, mostly from animal products. Some monasteries developed the "fish-beaver loophole." Beavers swim, therefore they're fish, therefore beaver is allowed during fasts. They ate beaver regularly during Lent. The butter consumption during fasts was so high that special dispensations were required. Some monasteries paid annual fees to the Church for permission to use butter during Lent. The "butter towers" in some European cathedrals were funded by these fees. The theological acrobatics existed because the monks learned through experience: you can't maintain health and work capacity without animal protein and fat. The fasting rules that eliminated meat made them weak. The butter, eggs, and cream kept them functional. The average monk outlived contemporary peasants by 10-15 years despite same living conditions. The difference was that during 150 "fasting" days annually, monks ate butter and eggs while peasants ate bread. The Church stumbled into optimal nutrition through theological loopholes. They banned red meat but allowed everything else that mattered. The monks were healthier during "fasts" than peasants were during feasts. Because butter, cream, and eggs are complete nutrition regardless of what you call them.
