Is There an App That Tracks Calories and Fasting?

Yes — A Few Apps Combine Calorie Tracking With Fasting Timers

Intermittent fasting (IF) has become one of the most popular dietary strategies worldwide. A 2025 survey by the International Food Information Council found that 14% of American adults practiced some form of intermittent fasting in the past year, making it the third most followed dietary pattern after general calorie counting and high-protein eating.

But here is the problem that the fasting community does not talk about enough: intermittent fasting without calorie awareness frequently fails.

A 2024 systematic review published in Obesity Reviews examined 23 randomized controlled trials comparing intermittent fasting to continuous calorie restriction. The conclusion: IF produced equivalent weight loss to standard calorie restriction when total calorie intake was controlled, but produced significantly less weight loss when participants fasted without tracking calories. The reason is straightforward — many people compensate for fasting hours by overeating during their eating window.

This makes the combination of fasting tracking and calorie tracking not just convenient but functionally necessary for most people who want IF to actually produce results.

Why Separate Apps Create a Problem

Many people currently use one app for fasting (like Zero) and a separate app for calorie tracking (like MFP or Cronometer). This split creates several issues.

Data lives in two places. You cannot see your calorie intake overlaid with your fasting window in a single view. Understanding how your eating pattern relates to your calorie total requires mental gymnastics or manual cross-referencing.

No window-aware calorie insights. A fasting-only app does not know if you consumed 1,400 or 2,400 calories during your eating window. A calorie-only app does not know if you are in a fasted or fed state. Neither app can tell you "you are 30 minutes into your eating window and have already consumed 80% of your daily budget."

Double the logging friction. Every meal requires interaction with two apps — starting/stopping timers in one and logging food in the other. Friction is the enemy of adherence, and doubling it is counterproductive.

App-by-App Comparison

Nutrola

Nutrola integrates fasting support directly into its calorie tracking system. You can set your preferred fasting protocol (16:8, 18:6, 20:4, OMAD, or custom windows), and the app tracks your fasting timer alongside your calorie and macro intake.

During your eating window, every meal logged — via photo AI, voice, barcode scanner, or manual search — counts against both your daily calorie budget and your eating window timeline. You can see at a glance how much of your budget remains and how much time is left in your eating window. This integrated view prevents the most common IF mistake: backloading too many calories into the final hour of the window.

The calorie tracking side uses Nutrola's full feature set: 1.8 million nutritionist-verified food entries, photo AI recognition, voice logging, recipe import from YouTube/TikTok/Instagram, and a 500K+ recipe library. At €2.50/month with no ads, it provides a combined fasting and tracking experience without requiring two subscriptions.

Zero

Zero is the most popular dedicated fasting app, and for good reason. Its fasting timer is elegantly designed, the interface is clean, and the fasting education content is thorough. Zero tracks fasting streaks, offers guided fasts, and provides journal prompts for reflection.

What Zero does not do is track calories. At all. There is no food database, no macro tracking, no meal logging. Zero tells you when to eat and when to stop. It has no insight into what or how much you eat during your window. For fasting timing alone, Zero is excellent. For combined tracking, you need a second app.

Simple

Simple attempts to bridge the gap by combining a fasting timer with basic calorie tracking. The app includes a food database, meal logging, and eating window management in a single interface.

The execution is mixed. The fasting timer works well. The calorie tracking is functional but less robust than dedicated trackers — the food database is smaller, there is no photo AI or voice logging, and the nutritional data is not consistently verified. Simple also uses a behavioral coaching approach with daily lessons and check-ins, which some users find helpful and others find intrusive. Pricing starts at $14.99/month, making it one of the more expensive options.

MyFitnessPal

MFP is a strong calorie tracker with a large (crowdsourced) food database but offers no fasting features whatsoever. There is no fasting timer, no eating window tracking, and no protocol management. MFP treats every day as a continuous eating period.

Using MFP for the calorie side and Zero for the fasting side is a common combination, but it splits your data across two apps with the friction issues described above.

Cronometer

Cronometer offers basic fasting tracking through its "fasting timer" feature, which records fasting and eating periods. The integration with its detailed nutritional tracking is useful — you can see when you ate relative to your fasting schedule.

The fasting feature is functional but minimal compared to dedicated fasting apps. There are no fasting streaks, no protocol presets, and limited fasting-specific insights. Cronometer's strength remains micronutrient detail rather than fasting support. The free tier includes ads; Gold costs $5.99/month.

Feature Comparison Table

Feature	Nutrola	Zero	Simple	MFP	Cronometer
Fasting timer	Yes	Yes (core)	Yes	No	Basic
Protocol presets (16:8, OMAD, etc.)	Yes	Yes	Yes	N/A	Limited
Fasting streaks	Yes	Yes	Yes	N/A	No
Calorie tracking	Yes (full)	No	Basic	Yes (full)	Yes (detailed)
Photo AI logging	Yes	N/A	No	Premium (limited)	No
Voice logging	Yes	N/A	No	No	No
Verified food database	Yes (1.8M)	N/A	Partial	Crowdsourced	USDA/NCCDB
Combined window + calorie view	Yes	N/A	Yes	N/A	Basic
Window-aware meal suggestions	Yes	No	Limited	No	No
Price	From €2.50/month	Free / $9.99/month	$14.99/month	Free / $19.99/month	Free / $5.99/month
Ads	None	Yes (free tier)	No	Yes (free tier)	Yes (free tier)

Why Combined Tracking Produces Better Results

The research on intermittent fasting outcomes consistently shows that calorie control is the mediating variable. IF does not produce weight loss through fasting physiology alone — it produces weight loss by creating a calorie deficit through time-restricted eating. When the deficit does not materialize because people overeat during their window, the weight loss does not materialize either.

A 2024 study from the University of Illinois at Chicago followed 200 participants practicing 16:8 IF over 12 weeks. The group that tracked calories during their eating window lost an average of 4.8 kg. The group that fasted without calorie tracking lost an average of 1.7 kg. Both groups followed the same fasting protocol. The only difference was calorie awareness.

The researchers attributed the difference to "compensatory eating" — the tendency to eat larger meals or choose more calorie-dense foods during the eating window, often unconsciously, as a response to the perceived deprivation of the fasting period. Calorie tracking during the eating window counteracted this compensation by providing real-time feedback on intake.

Optimizing Your Eating Window With Calorie Data

When fasting and calorie tracking are combined in a single app, several optimization strategies become possible.

Front-load protein. Research from the University of Missouri (2023) found that consuming 30-40g of protein in the first meal after a fast improved satiety throughout the eating window and reduced total calorie intake by an average of 12%. An integrated app can show you whether your first meal hits this protein threshold.

Distribute calories evenly. Rather than eating a small lunch and a massive dinner within your 8-hour window, distributing calories more evenly (40%/30%/30% across three eating-window meals) produces more stable energy and lower late-evening hunger. Combined tracking makes this distribution visible.

Use remaining budget for meal selection. With two hours left in your eating window and 500 calories remaining, Nutrola can suggest recipes from its 500K+ library that fit within that exact budget. This prevents the common pattern of arriving at the last meal with either too many or too few calories to allocate.

Track fasting compliance alongside calorie compliance. Seeing both metrics together — "I fasted for 16.5 hours AND ate 1,650 calories" — provides a complete picture that neither metric alone can offer. Streaks and trends become meaningful when they reflect both timing and quantity.

Common IF Protocols and How Combined Tracking Helps Each

16:8 (most popular). Eight-hour eating window. Combined tracking helps distribute 3 meals within the window while staying under calorie target. Nutrola's meal suggestions adapt to remaining budget and remaining time.

18:6. Six-hour window, typically 2-3 meals. Combined tracking is even more important here because fewer meals mean each meal's calorie impact is proportionally larger. A 200-calorie miscalculation on one of two meals represents a 10-15% daily error.

20:4 (Warrior Diet). Four-hour window, usually 1-2 meals. Combined tracking ensures the condensed eating period still hits macro targets, particularly protein. Without tracking, 20:4 practitioners commonly undershoot protein needs.

OMAD (One Meal a Day). Single meal, single calorie target. Combined tracking verifies that one meal provides adequate nutrition. The margin for error is zero — if the single meal is inaccurate, the entire day's data is wrong.

Frequently Asked Questions

Does eating during the fasting window break the fast in all apps?

In Nutrola, logging a food item automatically pauses or ends a fasting timer if the item contains calories. Non-caloric items (black coffee, water, plain tea) can be configured to not break the fast. Zero handles this similarly with its "fast-safe" food list. Simple also differentiates between caloric and non-caloric intake during fasts.

Can I track both 16:8 fasting and daily calorie targets simultaneously?

Yes. Nutrola, Simple, and Cronometer all allow you to set a fasting protocol and a daily calorie target independently. Nutrola goes further by showing your remaining calorie budget relative to your remaining eating window time, so you can pace your intake effectively.

Is intermittent fasting more effective than just tracking calories?

The research is clear: for weight loss, total calorie intake matters more than meal timing. A 2024 meta-analysis in the New England Journal of Medicine found no significant difference in weight loss between IF and continuous calorie restriction when calories were matched. IF is a strategy for creating a deficit — not a replacement for knowing your intake. Combined tracking ensures IF actually produces the deficit.

Which fasting app has the most accurate calorie tracking?

Among apps with both features, Nutrola offers the most accurate calorie tracking due to its 1.8 million-entry nutritionist-verified database. Simple uses a smaller, partially verified database. Cronometer's database is highly accurate (USDA/NCCDB sourced) but its fasting features are minimal. Zero has no calorie tracking at all.

Can I use Nutrola's photo AI during my eating window for faster logging?

Yes. Photo AI logging is available whenever you log a meal. During your eating window, snap a photo of your plate and Nutrola identifies the food, calculates macros from its verified database, and updates both your calorie budget and your eating window timeline simultaneously. Voice logging is equally fast — say what you are eating and the app handles the rest.