Intermittent fasting tracker and 16:8 timer

How it works in FORM

1. Pick a scheduleChoose 12:12, 14:10, 16:8, 18:6, 20:4 or OMAD. If you’re new to fasting, a shorter window is easier to keep.
2. Start the timerStart the fast when you finish your last meal. The timer shows how far into the fast you are.
3. Add the widgetPut the Fasting widget on your iPhone Home Screen or Lock Screen to see progress without opening the app.
4. End the fast and log the mealStop the timer when you eat. The fast goes into your history and streak, and the meal goes on today.

The first number is hours fasted, the second hours eating. 12:12 is roughly an overnight fast with no late snacks. 16:8 usually means skipping breakfast or eating dinner early. 20:4 and OMAD, one meal a day, are demanding, and fitting enough food into one sitting gets hard.

What the research says

Fasting is often sold with big claims. The evidence is more modest. Most trials find that time-restricted eating leads to weight loss when, and because, people end up eating less. When researchers compare it head to head with ordinary daily calorie restriction at the same intake, results tend to look similar. A 12-month trial published in the New England Journal of Medicine in 2022 found no significant difference in weight loss between calorie restriction with an 8-hour eating window and calorie restriction alone.

So fasting is a scheduling tool. For some people a fixed window makes eating less easier: fewer decisions, no late-night snacking. For others it leads to large, rushed meals and a hungry afternoon. Neither result is a failure. The question is which structure you can keep.

Starting without forcing it

• Start short: 12:12 or 14:10 for a week or two, then move the window by an hour if it feels easy.
• Keep the window steady: a schedule that shifts by four hours every weekend is hard to settle into.
• Open with a real meal: protein and some fiber keep you full longer than a pastry and a coffee.
• Watch the rebound: if you overeat every time the window opens, the schedule isn’t doing its job. Shorten it or drop it.
• Missed fasts: a broken fast is just a shorter one. Start again at the next meal.

Check with a doctor first if this is you

Fasting isn’t for everyone. If you’re pregnant or breastfeeding, have a history of an eating disorder, or take medication for diabetes, such as insulin, talk to your doctor before you change when you eat. The same goes for anyone under 18, and anyone whose condition or medication depends on regular meals. FORM tracks the clock. It doesn’t give medical advice.

What FORM tracks

• Schedules: 12:12, 14:10, 16:8, 18:6, 20:4 and OMAD. Switch when your week changes.
• Timer: start it when you finish eating, stop it when you break the fast.
• History: past fasts, so you can see what you actually did across weeks, not what you planned.
• Streak: a running count for people who like one, and easy to ignore for people who don’t.
• Widget: the Fasting widget shows progress on the iPhone Home Screen and Lock Screen.

Fasting and the rest of the day

A fasting window changes when you eat, not what your body needs. Your calorie and protein targets stay the same, and that matters most on short windows. Fitting 160 g of protein into four hours is hard. On 20:4 or OMAD, check the macro tracker before the window closes, not after.

If you train, notice where the session falls. Some people lift well fasted, others feel flat. Log workouts and meals on the same day and look at how sessions go over a few weeks. A late window can also push dinner close to bedtime. If your watch’s sleep data looks worse on late-eating days, try moving the window earlier.

Meals eaten in the window are scored like any other, and they feed the daily Health Score through protein, fiber, meal quality and calories near target. The hours you fast don’t add points on their own. Water does, and the water tracker logs it during the fast too. If you want the math behind eating less without the clock, calorie deficit explains it.

FAQ