Proper Fasting is an intermittent fasting timer that shows what happens in your body while you fast, based on published research. Your data stays on your phone.

Start a fast with one tap. The dial shows how far you are, which phase you are in and what comes next. Widgets on your home screen update every minute, so you can follow along without opening the app.

FREE
• A fasting timer with plans from 12:12 to 24 hours
• The phases of a fast, from digesting to fat burning and autophagy, each explained in plain words
• An estimate of how much lighter each fast makes you compared with eating at maintenance, counted only beyond a normal 12 hour overnight break
• Water tracking with your own glass and bottle sizes
• Streaks that follow your rhythm, with rest days, so one missed day does not undo weeks of effort
• Reminders, a goal notification and a quiet progress notification
• A small ring widget for your home screen that counts up or down, in dark and light
• A simple fasting dial on your Wear OS watch
• Advice on breaking a longer fast gently
• Export and import of your data, and import from other fasting apps via CSV

PRO, PAID ONCE
• All widgets: the full dial, the streak calendar, the standard and the mini widget
• Wear OS: the full dial with phases and weight, a watch face complication and heart rate
• Training from heart rate: see what your workouts add on top of the fast
• Hormone and fuel charts hour by hour, with the studies behind them
• Fasts of 36, 48 and 72 hours, or any goal you set yourself
• Your full history and the patterns in your journal
• Weight trend, ketone and glucose readings, measurements and progress photos
• Fasting on chosen weekdays or a few times a week, and fasts that start on time by themselves

Choose a Year Pass that never renews by itself, or Lifetime. There are no subscriptions and nothing to cancel. If a Year Pass ends, nothing is deleted.

SCIENCE, NOT HYPE
The curves and phase timings are estimates for a healthy adult, taken from human studies where they exist. Each one links to its sources in the app. Where the evidence comes from animal studies, the app says so.

PRIVATE BY DESIGN
No account, no ads and no analytics. Your fasts, body data and heart rate stay on your device.

PLEASE READ
Proper Fasting gives general information and is not medical advice. Talk to your doctor before you start fasting, especially if you take medication or have a medical condition. Fasting is not suitable for children, teenagers, pregnant or breastfeeding women, people with a history of eating disorders, or people who are frail or underweight.