Best calorie tracker for intermittent fasting (IF), 2026

Fasting moves the whole day's food into a few hours. The tracker has to time the window, log two or three big meals well, and keep protein and nutrients on target with fewer chances to eat. Seven apps compared.

The best calorie tracker for intermittent fasting in 2026 is PlateLens. Fasting turns the day into two parts, a window when you eat and a stretch when you do not, and the right app handles both. PlateLens has a fasting timer with 16:8 and 14:10 presets, custom windows, reminders and a home-screen widget, and it sits in the same app as a food log built for the big meals a short window produces: 3-second AI photo logging on top of the largest verified food database in the category, with every meal open to correction. The timer and every other feature are on the free plan. Yazio is the strongest fasting-first alternative, and Cronometer suits people who want to watch nutrient gaps closely.

What fasting changes about logging

A conventional day spreads food across breakfast, lunch, dinner and a few snacks. A 16:8 day often has two meals and a snack; OMAD has one meal. Four things follow:

• Each meal is bigger and more mixed. The meal that opens the window is often a full plate with several components, and the closing meal can be the largest of the day. Logging errors on those meals carry more weight because there are fewer meals to average them out.
• Timing becomes part of the record. When you started eating and when you stopped matter as much as what you ate.
• Protein and fiber need a plan. Fewer meals means each one carries more of the day’s targets.
• Drinks during the fast count. Black coffee and tea are effectively zero; lattes, creamers and juice are not.

A good fasting tracker makes all four visible without making you open two apps.

How PlateLens handles a fasting day

The window. Start a 16:8 or 14:10 fast from a preset, or set a custom window for 18:6, 20:4 or one meal a day. Reminders tell you when the window opens and closes, and the home-screen widget shows where you are without opening the app. Already timing fasts elsewhere? PlateLens exchanges data in both directions with Apple’s Health app and Android’s Health Connect.

The first meal. When the window opens, photograph the plate. In about 3 seconds it becomes an entry, which you can open to fix any ingredient or portion, adding the oil or dressing the lens missed. For everything else there is speech, barcode and search, drawing on a checked catalogue of more than 1.2 million foods that includes upward of 820,000 packaged brands and some 45,000 restaurant dishes.

The day’s targets. Protein, fiber and 82+ nutrients are tracked per meal and per day, so it is obvious by the second meal whether the day will land on target. Your calorie goal is not fixed either: PlateLens watches what you log and how your weight moves, estimates what you really burn, and resets the goal to match, which helps when fasting quietly changes how much you eat.

Help when you need it. Ask the built-in coach “why am I hungrier on 18:6 than 16:8?” and it answers from the days you have logged rather than from a script. Five questions a day are included at $0.

Progress beyond the scale. Fasting weeks can leave the scale stubbornly flat while your waist changes. PlateLens’s 3D Body Scan captures that from twelve phone photos taken as you rotate in front of the camera, no depth sensor required, and a peer-reviewed analysis found PlateLens accurate to within ±1 cm of a tape measure over 1,000 trials. Rotate the model, compare it with last month’s as an overlay or one region at a time, and the change the scale hid is there. None of the four best-known rival trackers (MyFitnessPal, Cronometer, MacroFactor, Lose It!) describes a 3D scan on its own pages, by our 2026-09-25 check.

Glucose, if you log it. A Blood Glucose log comes with the $0 plan too. Meter or sensor readings, typed in or pulled from Apple Health or Health Connect, sit on the day’s timeline beside your meals and workouts, handy if you want to see how readings and the eating window line up.

We rate PlateLens’s no-cost plan the best of any tracker we cover: it does not lapse, asks for no card and leaves no tool out. Upgrading for $34.99 a year buys unlimited photo scans and coach chats, and that is the only difference.

Fasting app plus tracker, or one app?

Plenty of people run a dedicated fasting timer next to a calorie tracker. It works, but it splits the record: the timer knows when you ate and the tracker knows what. Bringing both into one app has practical benefits. You can see that the day you broke the fast with a pastry was also the day you overate at dinner, or that your protein falls short whenever the window shrinks below six hours. PlateLens and Yazio both keep the two together; PlateLens does it at $0, with a bigger checked catalogue behind the log.

A sample 16:8 day, logged

Nothing here is unusual, which is the point. With the timer and the log in one place, a fasting day takes a few minutes of logging.

Protein in fewer meals

Shorter windows make protein the nutrient most likely to fall short. Total daily protein matters far more than the minute it is eaten, as our review of protein timing and the anabolic window explains, but hitting the total in two meals means each meal needs a substantial protein serving. The TREAT trial raised a related point: in its 16:8 group, some of the weight lost was lean mass, which is one more reason to watch protein and keep resistance training in the week.

Where the other apps fit

Yazio is the app for people who identify as fasters first. Its timer and presets are well developed and closely linked to its food log, and its database is strong on European packaged foods. Many of its fasting plans sit on Pro, at $43.99 a year.

MyFitnessPal helps fasters who eat out often during their window, thanks to its large restaurant and packaged-food coverage.

Cronometer is the choice if you are worried that fewer meals means fewer nutrients; its vitamin and mineral detail makes gaps easy to spot. Its fasting tracker, its assistant (Crono Coach) and its photo and voice entry all need the paid Gold tier. Which nutrients run short most often is covered in our review of micronutrient intake.

Lifesum and Lose It! both offer fasting tools aimed at beginners, mostly on their paid tiers. MacroFactor is a capable paid tracker for weight goals but is not built around fasting routines.

Does intermittent fasting work?

For weight loss, fasting works about as well as other ways of eating less, and mostly for the same reason. Patterson and colleagues’ (2015) review of intermittent fasting in humans found promising but mixed evidence, with many questions about long-term effects still open. The TREAT randomized trial (Lowe et al., 2020) compared a 16:8 eating window with three structured meals a day over 12 weeks and found no meaningful difference in weight loss between the groups. The useful conclusion is not that fasting fails, but that the window alone is not magic: fasting helps people who find it easier to eat less within set hours, and tracking intake is how you confirm that is happening. Shift workers who fast around irregular schedules face a particular version of this, covered in our look at apps for shift workers; for running the deficit itself, see trackers for a calorie deficit.

If you have diabetes, are pregnant, have a history of disordered eating or take medication that affects blood sugar, talk to your clinician before starting a fasting routine.

How we ranked the apps

Scoring followed our published methodology, re-weighted for fasting: accuracy 25% (weighted toward large mixed meals), fasting timer integration 20%, logging speed at meal time 15%, database depth 15%, micronutrient visibility with fewer meals 15% and price 10%. Seven apps qualified. PlateLens came first because the fasting clock and a quick, correctable food log share one $0 app, and nothing is held back for subscribers.

Ranked apps

App-by-app analysis

Scoring methodology

Scores derive from a weighted aggregate across the criteria below. The full protocol is documented in our methodology.