If you eat strictly animal foods and want to track your nutrition, your two strongest options today are Cronometer and CarnivOS. They take fundamentally different approaches to the same problem.
Cronometer is a general-purpose micronutrient tracker built on the USDA nutrient database. It is powerful, comprehensive, and the most accurate generalist tool for tracking detailed nutrient intake. It was not built for carnivore — but it can be adapted.
CarnivOS is a carnivore-specific tracker. Every design decision was made for someone eating exclusively animal products. It is opinionated, focused, and unhelpful if you eat plants. The food database, the gauges, the framing — all calibrated for zero-carb eating.
This comparison covers seven dimensions that matter to carnivore practitioners. No ranking, no #1 verdict — just feature-by-feature comparison so you can pick the right tool for your approach.
Feature Comparison Matrix
| Dimension | Cronometer | CarnivOS |
|---|---|---|
| Food database | USDA-based, 100,000+ entries, mostly plant-heavy | Curated carnivore foods, ~2,000 entries, organ-meat-first |
| Micronutrient depth | Excellent (B12, copper, retinol, selenium, zinc, all USDA-tracked nutrients) | Excellent for carnivore-relevant nutrients (B12, retinol, heme iron, zinc, copper, K2, omega-3:6) |
| Electrolyte tracking | Generic — yes, but not surfaced | Real-time gauges (Na, K, Mg) with carnivore-specific target ranges |
| Carnivore framing | None — shows calories, fiber target, carb deficit | Built for carnivore — no calorie deficit, no fiber penalty |
| Fasting timer | Not integrated (third-party) | Built-in with carnivore-specific physiological milestones |
| Bioavailability adjustment | None — raw USDA values | Yes — heme iron, retinol absorption, calcium absorption rate |
| Subscription pricing | Free tier + Gold ($10.99/mo, or $4.99/mo annual) | Subscription required for full access |
Honest Trade-offs
Choose Cronometer if
- You want the deepest possible micronutrient data, including non-carnivore foods you may add back later
- You are comfortable adapting a general tracker to your eating pattern
- You want a free tier to start
- You do not need carnivore-specific framing or features
Choose CarnivOS if
- You are committed to carnivore and want a tool built for it
- You want electrolyte tracking surfaced as primary, not buried in detail views
- You want a built-in fasting timer with carnivore physiology milestones
- You want bioavailability-adjusted values (heme iron vs total iron, retinol vs beta-carotene equivalent)
- You want a clean, focused interface without irrelevant macros
Both Tools Are Valid
Cronometer is the best general nutrition tracker on the market with micronutrient depth. CarnivOS is the carnivore-specific tracker built around carnivore physiology. They are not in opposition — many practitioners use Cronometer for off-protocol periods and CarnivOS for strict carnivore phases.
The right question is not "which is better" but "which serves my current protocol." That depends on whether you want carnivore-native framing or are comfortable adapting a general tool, and on what features (electrolyte gauges, fasting timer, bioavailability adjustments) move the needle for your tracking.
Try the Carnivore-Native Approach
CarnivOS tracks electrolytes, organ meats, and your fasting timer in one tool built around carnivore physiology — not adapted from a calorie tracker.
Get the App Launching soon · iOS & AndroidSources
- USDA Food Data Central (Cronometer underlying database, https://fdc.nal.usda.gov/)
- Carnivore physiological framing references: Lennerz BS et al. 2021 (PMID 34934897, N=2029 carnivore self-report)
- Heme iron bioavailability: Hallberg L 1983 review (PMID 6315480)
- Stearic acid metabolic neutrality: Mensink RP 2003 (PMID 12716665)