Hi Product Hunt 👋 I'm Vincent, and I built FastFlow because the fasting apps I tried treated my watch like a paperweight. I'm in my 60s. I fast and I train Zone 2, and I kept wanting one simple thing: for my fast to actually use the sensors already on my wrist. Every fasting app I found was a phone-based countdown timer. Garmin's own store had a couple of hobbyist fasting widgets, but none had an iOS companion or synced live. So FastFlow reads your Garmin (and Apple Watch) in real time over BLE. As you fast, it shows your heart rate, HRV, Body Battery and stress, and coaches you through six metabolic stages — Fed, Clearing, Shifting, Burning, Cleansing, Renewing — so you understand what's happening, not just how many hours are left. There's a Live Activity and Dynamic Island so it's always a glance away. The philosophy behind it is Wu Wei — effortless action, working with the body's natural intelligence instead of forcing it. No hustle, no diet-culture guilt. Just calm, longevity-minded tools. Free to start; a small Premium unlocks the deeper coaching. I'll be here all day answering everything — I'd genuinely love your feedback and your fasting/Zone 2 questions.

FastFlow

Fasting tracker that reads your Garmin live

Fasting tracker that reads your Garmin live