One of the more curious phenomena I’ve observed—and that many others report—is the dramatic reduction in stool volume when shifting to a nearly all-animal diet. At first glance, it might seem alarming. But when you consider the digestive mechanics and microbial ecology involved, it begins to make perfect sense.
Animal-based foods are remarkably bioavailable. Proteins, fats, and micronutrients from meat, eggs, and dairy are absorbed with astonishing efficiency in the small intestine. Unlike plant matter, which often contains insoluble fiber and resistant starches that escape digestion, animal foods leave very little residue. So if there’s almost nothing left to pass through the colon, why would we expect much stool at all?
The answer lies not just in digestion, but in the invisible world of microbes. It’s estimated that up to 80% of stool mass is composed of dead microorganisms—bacteria that thrive on fermenting indigestible plant fibers. Remove the fiber, and you remove their fuel. Remove their fuel, and their population shrinks. Fewer microbes mean less turnover, less biomass, and ultimately, less stool. It’s not dysfunction—it’s metabolic efficiency.
This shift transforms the colon from a bustling fermentation chamber into a quieter transit zone. The microbial landscape adapts: fiber-loving species like Bifidobacteria fade, while bile-tolerant strains may gain a foothold. But even they don’t flourish without substrate. The gut becomes a leaner ecosystem, and the rhythm of elimination slows. Many carnivore dieters report going every other day—or even less frequently—with no discomfort. As long as stools remain soft and easy to pass, this isn’t constipation. It’s a reflection of reduced waste.
Of course, this transition isn’t without nuance. The absence of fiber means fewer short-chain fatty acids like butyrate, which normally support gut lining integrity and motility. Hydration, salt intake, and dietary fat become more important to maintain balance. And for those tracking their own adaptation, it’s worth noting how stool consistency, satiety, and energy levels evolve over time.
In essence, the carnivore gut is a study in minimalism. Less input, less output—but not less function. It’s a metabolic pivot that invites us to rethink what elimination really means. Not just the disposal of waste, but the echo of microbial life, shaped by what we choose to feed it—or not.