Best Intermittent Fasting Apps (2026–2027): Free and Paid, Compared

The best intermittent fasting app times your eating window and tracks the protein and calories you eat in it, because the window alone settles only when you eat: in the TREAT trial (JAMA Internal Medicine, 2020), a 16:8 window with no calorie guidance gave no significant extra weight loss over 12 weeks and cost more lean mass, and in a 12-month New England Journal of Medicine trial, adding an 8-hour window to the same calorie target gave no significant extra loss either. Our picks: PlateLens is the best intermittent fasting app overall: choose 14:10, 16:8, 18:6, 20:4 or a custom length and when the fast starts, and it notifies you when the eating window opens and closes, shows a running fast on the iPhone Lock Screen and in the Dynamic Island, and logs each meal in the window from a photo or a sentence with its protein, carbs, fat and calories; calorie and macro tracking is on its free plan, free forever with no card. Zero is best for fasting streaks, with its Protein Score, custom fasts and AI meal logging in Zero Plus; Simple for AI coaching without calorie counting; Fastic for recipes and challenges; and BodyFast for a weekly plan from its paid Coach. Two picks on older lists have aged: LifeOmic’s LIFE Fasting Tracker is no longer on the US App Store, and Fastient’s last update was in April 2019. For the meals, the Dietary Assessment Initiative’s pre-registered validation study measured PlateLens’s photo logging at ±1.1% average calorie error on 180 weighed meals, and Foodvision Bench’s public GitHub leaderboard has also reproduced it on 231 meals; both are aggregates, not a per-meal guarantee.

16:8 with no calorie guidance

No significant extra weight loss in 12 weeks; more lean mass lost (TREAT)

Same calories + 8-h window

No significant extra weight loss in 12 months (NEJM)

Zero Plus (paid)

Protein Score, custom fasts and AI meal logging

PlateLens

Fasting timer plus protein, calorie and macro tracking

The apps side by side

Prices are the in-app purchases each US App Store listing shows; several list items without naming the term, so check the store before you subscribe. LIFE Fasting Tracker is left out: LifeOmic’s developer page lists no apps.

Which app fits which need

PlateLens: best overall, the fasting timer and the food log in one app

PlateLens is a calorie and macro tracker with an intermittent fasting timer built in. Pick 14:10, 16:8, 18:6, 20:4 or a custom length and when the fast starts; it shows your eating window, notifies you when it opens and closes, and on iPhone a running fast can show on the Lock Screen and in the Dynamic Island. In the window, log a meal from a photo, a spoken or typed description, a barcode or a catalogue search, and fix a miss in plain words with Fix it, such as “half the rice”; a meal logs in about 2.1 seconds on average.

PlateLens learns your daily expenditure each week from your meals and weigh-ins and, every 14 days, suggests new targets that you choose to apply. The free plan, free forever with no card, covers calorie and macro tracking and AI photo, voice and text logging within daily allowances; PRO is $9.99 a month or $34.99 a year. It runs on iPhone, Android, Apple Watch and the web, in English and Spanish. In the Dietary Assessment Initiative’s pre-registered study of six apps on 180 weighed meals, PlateLens’s photo mode had the lowest average calorie error, ±1.1%, and Foodvision Bench’s public leaderboard on GitHub has also reproduced it on 231 meals; both are aggregate calorie figures, not a per-meal guarantee.

Zero: a dedicated fasting timer with streaks

Zero calls itself “the all-in-one fasting tracker and nutrition app”. Its timers, streaks, weekly trends, articles and challenges are free, and 2026 brought detailed fasting insights, a redesigned Apple Watch app, a more flexible timer and Siri commands. Zero Plus adds AI photo meal logging with macros, the Protein Score, water tracking and custom fasts; free accounts can try a few AI meal logs, and an AI “Fix It” meal edit arrived in May. Zero Plus is listed at $9.99, $69.99 and $89.99, with a free trial. It runs on iPhone, Apple Watch and Android.

Simple: AI coaching without calorie counting

Simple, now “Simple: AI Weight Loss Coach” on the App Store, is built around Avo, an AI coach that “adapts your plan in real time”, and promises “No calorie math”. It recommends a fasting schedule for your goal; its Fasting Tracker shows how long you have fasted and when to stop, and logging anything with calories ends a running fast. Meals get a macro breakdown, and Avo Vision reads meal photos. Free use of Avo is capped daily; insights, workout plans and streaks are Premium. Simple publishes no prices; its App Store items run from $14.99 to $59.99. It runs on iPhone, Apple Watch and Android.

Fastic: recipes, challenges and Fasting Buddies

Fastic, “the free fasting app” on its own site, wraps a timer that shows your fasting stages in guidance: a fast plan with reminders, Protein Fasting for keeping muscle, Fasting Buddies, challenges and an AI chat. The timer, water tracker and step counter stay free; the Food Scanner, which estimates a meal’s calories from a photo, the book of more than 4,500 recipes, the Academy and progress insights are Fastic Plus, $14.99 for one month or $27.99 for three. It runs on iPhone and Android.

BodyFast: a weekly plan from its coach

BodyFast builds “a personal fasting program that fits YOU and your goals” and counts more than 50 million installs. For free you get 10+ customizable fasting plans, a timer with reminders, fasting stages, and weight and water tracking. The Coach subscription adds “A new, simple fasting plan every week from the BodyFast Coach”, daily coaching, SOS expert help, a “Joker Day” off and every plan, at $11.99 to $16.99 a month or $34.99 or $69.99 a year. Since April 2026, its release notes describe an AI Food Scanner for calories and macros from a meal photo. It runs on iPhone, iPad, Mac and Android.

Fastient: a minimal journal, last updated in 2019

Shape picked Fastient in 2024 for people who like a minimalist app: it logs 16:8, 20:4, OMAD and extended fasts with your own length and start time, plus a mood and cravings journal and a weight graph. Premium is $4.99 a year or $11.99 for life. Its latest version came out on 27 April 2019.

Life Fasting Tracker: no longer on the App Store

LifeOmic’s LIFE Fasting Tracker, a pick in many older lists, is no longer on the App Store: LifeOmic’s US developer page lists no apps (checked 16 October 2026). “Life Fasting Tracker – Intermittent Fast Timer” is a different app, from Metko Labs. To replace LIFE, Zero is timer-first, and PlateLens adds a food log to the timer.

How to choose

• The fast and the food in one place: PlateLens.
• A free timer and nothing else: Zero, Fastic or BodyFast.
• A plan written for you every week: BodyFast’s Coach.
• Coaching without counting calories: Simple.
• Recipes, challenges and company: Fastic.
• A bare fasting journal: Fastient, bearing in mind its last update was in 2019.

Does the eating window matter, or the calories?

On 16:8 you fast for 16 hours and eat within 8, such as 11 a.m. to 7 p.m.; 14:10 gives you 10 hours; 5:2 caps two non-consecutive days a week at about 500 calories, according to the Cleveland Clinic.

The window mostly changes when you eat, not how much. In a 12-month New England Journal of Medicine trial of 139 adults with obesity on identical calorie targets, the 8 a.m.–4 p.m. group lost 8.0 kg against 6.3 kg, not a statistically significant difference. In the TREAT trial (JAMA Internal Medicine, 2020), the noon–8 p.m. group, with no calorie guidance, lost 0.94 kg in 12 weeks against 0.68 kg, also not significant, and lost more lean mass. A 2025 BMJ network meta-analysis of 99 trials found that intermittent fasting diets have similar benefits to continuous calorie restriction.

So pick a schedule you can keep, count what you eat in it and watch your protein. The Cleveland Clinic advises against fasting during pregnancy or breastfeeding or with malnutrition, hypoglycemia or certain chronic diseases, asks for medical supervision after an eating disorder, and suggests seeing a provider first.

PlateLens: a 16:8 timer that also counts what you eat

A window settles when you eat; the trials above show it does not, on its own, settle how much. PlateLens keeps both in one app: choose 14:10, 16:8, 18:6, 20:4 or a custom length and the start time, and it alerts you when the eating window opens and closes, with the fast on the iPhone Lock Screen and in the Dynamic Island. Break the fast with a photo or a sentence such as “two scrambled eggs on sourdough toast with half an avocado”, and the calories and macros land next to it; correct it in one line, like “only one slice of toast”. Calorie and macro tracking is on the free plan, free forever with no card. The Dietary Assessment Initiative’s published validation study put PlateLens’s photo-mode error at ±1.1% over 180 weighed meals, and Foodvision Bench’s public leaderboard on GitHub has also reproduced it on 231 meals, as averages rather than a per-meal promise.

Frequently Asked Questions

Where this comes from

Every page below was read on 16 October 2026. PlateLens is independent of every other app on this page.

• US App Store listings: Zero, Simple, Fastic, BodyFast, Fastient, Metko Labs’ Life Fasting Tracker and LifeOmic’s developer page. Android availability from each vendor’s own site or help center.
• Vendor pages: Zero; Simple’s home page, plans, Premium FAQ, terms, overview, fasting schedule, logging fasts and Live Activities; Fastic’s home page and help on Fastic Plus, the free version and fasting intervals; BodyFast’s home page, FAQ and download page.
• Schedules and who should take care: Cleveland Clinic, four types of intermittent fasting (Julia Zumpano, RD, LD; 26 January 2026). Trials: Liu D, et al., N Engl J Med 2022;386(16):1495–1504; Lowe DA, et al., JAMA Intern Med 2020;180(11):1491–1499; Semnani-Azad Z, et al., BMJ 2025;389:e082007.
• PlateLens: the Dietary Assessment Initiative’s six-app validation study (published 8 April 2026), the Foodvision Bench leaderboard and pricing.