BodyFast, Zero, Yazio and Lifesum compared for 16:8 timers, adaptive coaching plans and food logging that pairs fasting with nutrition.
Fasting is simple to explain and genuinely hard to execute: the only things that matter are starting the window, ending it and repeating without drama, which is precisely the job a phone timer does better than willpower. The 4 apps in this guide approach that same discipline from different angles. Zero is the global benchmark for tracking the phases of the fast itself; BodyFast layers an adaptive weekly coach over more than ten protocols; Yazio and Lifesum extend the picture into the eating window with calorie counting, databases and diet quality. They were chosen for fasting-first and fasting-plus-nutrition users respectively. Fasting is not suitable for everyone; with any health condition, check with a professional first.
BodyFast pairs a fasting timer with a weekly adaptive Coach, 10-plus protocols, challenges and weight and water tracking, all clearly translated into Spanish.
BodyFast, developed in Germany, is among the most complete fasting apps on the stores. Beyond the basic timer, its weekly Coach suggests plans that adapt to your progress across more than ten protocols, starting gently and stepping up as results come, and it adds challenges, weight and water tracking and plain explanations of what to expect, which lowers the barrier for safe starts. The interface is clearly translated into Spanish. The personalised Coach is the paid feature, the free version carries ads, and the category itself carries the standard caution — fasting is not suitable for everyone.
Zero is the category benchmark — a timer showing each phase of the fast in real time with 16:8, 18:6, OMAD and custom protocols plus doctor-led content.
Zero is the world's most popular intermittent fasting app and the model many others imitate. Its timer covers the standard protocols — 16:8, 18:6 and OMAD — alongside custom windows, displaying the phases of a fast in real time and explaining what is happening in the body at each stage, with trend charts and educational material contributed by well-known doctors. Advanced statistics are locked behind payment, much of the content is in English only, and fasting itself remains unsuitable for some groups regardless of how good the app is.
Yazio pairs its fasting timer with a polished calorie counter — 4 million-plus foods, a clear daily budget and healthy recipes for controlling the eating window.
Yazio is a clean, highly visual calorie counter built with weight loss and intermittent fasting in mind, which makes it the natural pairing for anyone who realises that timing meals is only half the job. The daily calorie budget is presented plainly, the food database runs past four million entries and a library of healthy recipes supports the eating window rather than leaving it unmanaged. The free version is fairly limited, full meal plans and the recipe library are PRO-only, and advertising funds the no-cost tier.
Lifesum combines fasting timers with eating plans — keto, Mediterranean and more — and rates diet quality, not just the clock, in a polished interface.
Lifesum treats fasting as one option inside a wider nutrition product. Alongside the timer it offers eating plans including keto and Mediterranean diets, meal logging and, more unusually, an assessment of diet quality with personalised advice aimed at eating better rather than simply eating less, wrapped in one of the most attractive designs in the category. Its best features sit in Premium, full plans require a subscription, and the food database is somewhat smaller than MyFitnessPal's, so niche products may need manual entry.
Pros
Keto, Mediterranean and fasting plans
Rates the quality of your diet
Polished, motivating design
Cons
Best features live in Premium
Smaller database than MyFitnessPal
Full plans require a subscription
Download price only. In-app purchases and subscriptions may cost extra.
Questions & answers
Which fasting protocol should I start with?
16:8 — 16 hours fasting, an 8-hour eating window — is the standard entry point, in practice meaning skipping breakfast or dinner, and most people tolerate it well. Longer protocols such as 18:6 or OMAD are worth trying only after 16:8 feels comfortable. BodyFast makes the ramp particularly gentle, with its coach starting at 12:12 or 14:10 and stepping up from your response.
What can I drink during fasting hours?
Unlimited water, black coffee and unsweetened teas are the consensus, and they are what the apps' timers assume. Anything with calories — milk, juice, sugary drinks — breaks the fast. Sweeteners are debated rather than settled; for a strict approach, avoid them. Zero includes doctor-written articles explaining these edge cases in more depth.
Is intermittent fasting safe for everyone?
No. It is not advised during pregnancy or breastfeeding, for people with a history of eating disorders, for medicated diabetics because of hypoglycaemia risk, or for minors, among other groups. Anyone on long-term medication or living with a health condition should speak to their doctor before starting. For everyone else it is simply one more calorie-control tool: useful when it fits your life, never magic.
More related apps
App library · United States App Store. Prices and availability reflect the last check.
