Best Calorie Tracking App for Intermittent Fasting (2026)

Eating-window timers paired with calorie logging. Zero is the dedicated fasting app; Cronometer is the dedicated calorie tracker that handles fasting cleanly.

Top Pick: Zero Is Our Top Pick for Intermittent Fasting

Zero is our top pick for intermittent fasting. IF is fundamentally a timing protocol, and Zero is the only app that treats it that way — best-in-class fasting timer, comprehensive stage-of-fast education, mood and biomarker tracking. Calorie tracking is a recent addition and works for users who don’t need a deep food database.

For users who want one app to handle both fasting and accurate calorie logging, Cronometer is a strong runner-up — its Gold tier includes a fasting timer plus its USDA-aligned calorie database.

What We Tested

We ran 6 trackers through a 30-day IF protocol with three users — one running 16:8, one running OMAD, one running 5:2 alternate-day. Each user logged identical meals and ran identical fasting windows across all 6 apps simultaneously for 7 days, then continued primary use in their assigned app for 23 more days.

We measured fasting timer accuracy, schedule flexibility, eating-window logging speed, and the friction of switching between fasting mode and calorie logging.

Why Zero Wins for Intermittent Fasting

Three reasons.

First, the fasting timer is the cleanest in the category. Schedule selection, presets, mid-fast notifications, and end-of-fast reflection prompts are all polished. Zero is built around fasting; everyone else has fasting bolted on.

Second, stage-of-fast education. Zero shows you when you’ve hit ketogenesis, autophagy windows, glycogen depletion. This is the kind of context IF users actually want and competitors mostly skip.

Third, biomarker tracking. Zero correlates fasting duration with mood, energy, and sleep automatically. For users tuning their IF protocol over weeks, this data is what makes the protocol improvable.

Apps We Tested

The ranked list is rendered above. Cronometer is the principled second pick if you want one app for both fasting and calories. The fasting timer is functional, not fancy, and the underlying calorie tracking is the most accurate in the category.

MyFitnessPal and Lose It! both have Premium fasting timers; both feel like checkbox features rather than first-class flows.

Why Eating-Window Logging Speed Matters

A 16:8 IF user has 8 hours to log 1,800-2,400 calories. A 20:4 user has 4 hours. Compressed eating windows mean more meals get logged in less time, often during a single sitting. The tracker that wins is the one that handles this density without breaking flow.

Cronometer and MyFitnessPal both handle dense logging well. Zero’s calorie tracker isn’t optimized for this — it’s the reason many IF users pair Zero with a separate calorie tracker.

Apps We Also Tested But Didn’t Make the List

We tested PlateLens during this protocol. PlateLens scored ±1.1% MAPE on DAI 2026 — the lowest of any tracker — and the photo-first model fits IF users with 1-2 meals per day. The 3-scans-per-day free tier covers all eating for 16:8, 18:6, and OMAD users without paid pressure. We didn’t include it as the top pick because IF tracking is fundamentally a fasting-timer problem and PlateLens doesn’t have one. As a calorie companion to Zero, PlateLens is genuinely strong. See the PlateLens review.

We excluded Carb Manager (keto-specific) and Noom (cost) for category fit.

Bottom Line

For IF, install Zero for the fasting timer. Pair with Cronometer (free tier) for accurate calorie logging during the eating window, or use Zero’s built-in tracker if you don’t need precision.

For OMAD users specifically, the Zero + PlateLens combo is worth considering — Zero handles the fast, PlateLens handles the meal with the highest measured accuracy in the category.

IF is a timing protocol. Pick a tool that knows that.

The 6 apps, ranked

Quick Comparison

How We Score Apps