# Fast Signal — Fasting + keto + training + AI

> Fasting + keto + training + AI (iPhone/iPad app by Backbone Services.)

- Source: https://appshunter.io/ios/app/fast-signal/id6794531086 (this page in markdown: same URL + `.md`)
- Developer: [Backbone Services](https://appshunter.io/developer/6794531088)
- Category: Health & Fitness, Lifestyle
- Price: Free with in-app purchases
- Age rating: 4+
- Requires: iOS 17.0 · 5 MB
- Languages: American English
- Released: 2026-08-12
- Data updated: 2026-09-16
- User reviews in markdown: https://appshunter.io/ios/app/fast-signal/id6794531086/reviews.md

## What is Fast Signal?

Fast Signal connects your fasting, keto, and training data to the health metrics that actually matter — HRV, VO2 max, cardio recovery, sleep, and more.

WHY FAST SIGNAL Most trackers show you numbers. Fast Signal pulls your real Apple Health data and connects it to your fasting windows, keto adherence, and training load — so you can see what's actually moving the needle, not just log another data point.

THE FASTING TIMER, DONE RIGHT Start and end your fast with one tap. Watch the ring fill in real time, track your fasting window automatically, and see your prolonged-fast streak build over time.

TRACK WHAT MATTERS

Weight, body fat %, lean mass, and BMI
Interval runs, non-stop runs, and HIIT — auto-detected and tracked separately, with pace and heart rate
Resting heart rate, HRV, VO2 max, cardio recovery, and sleep
Keto adherence, junk food, alcohol, illness, travel, and mood
Weather and altitude context for every day
Set weekly goals and pin up to 3 favorite metrics to watch daily

AI-POWERED INSIGHTS Fast Signal reviews your week and month and narrates what's actually going on — in plain language, grounded in your real data, not generic advice. Insights account for real-world context, too: illness, travel, altitude, and weather, so a rough patch doesn't get mistaken for a bad trend.

LEARN AS YOU GO A built-in Learn tab covers the basics of intermittent fasting, keto, and the metrics Fast Signal tracks — so you always know what you're looking at and why it matters.

START FREE Track everything, start your first fast, and see your trends — free. Upgrade anytime to unlock AI-generated insights and expert-informed guidance.

Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/

## Pricing and in-app purchases

Base price: Free.

**Subscriptions**

| Subscription | Price | Period |
| --- | --- | --- |
| Insights Monthly | $3.99 | per month |
| Insights Yearly | $29.99 | per year |



## Version history (last 5 releases)

### 1.8 — 2026-09-07

- New advanced AI model for Insights
- UI Improvements
- Bug fixes

### 1.7.1 — 2026-09-04

Bug fixes

### 1.7 — 2026-09-02

- Manually override run classification
- Preparing the app for future improvements to Insights
- Minor bug fixes

### 1.6.2 — 2026-08-28

Bug fixes

### 1.6.1 — 2026-08-27

Bug fixes

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-09-16.*