# WTFatLite vs Undiet

The clearest difference is in-app purchases: WTFatLite at none against Undiet's 2. Undiet's advantage is ads (none vs shown) and update cadence (weekly vs every 3 months). On price, device support and iOS requirement there is nothing between them.

Both are free to download. Undiet sells 2 in-app purchases, starting at $5.99 per month. WTFatLite asks for nothing beyond the download.

WTFatLite ships an update every 3 months, Undiet weekly. The most recent releases landed on October 20, 2026 and October 26, 2026 respectively.

## The numbers

| Metric | WTFatLite | Undiet |
| --- | --- | --- |
| Price | Free | Free |
| Positive reviews | 0.0% of reviews | — |
| In-app purchases | **No** | Yes |
| Ads | Yes | **No** |
| Update frequency | Every 3 months | **Weekly** |
| Monetization | Ad-supported | — |
| Size | 6 MB | 43 MB |
| Requires iOS | **14.0** | 15.1 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPod |
| Age rating | 4+ | 17+ |
| Developer | [F-NET Apps](https://appshunter.io/developer/537078708) | [Krnic](https://appshunter.io/developer/1803578555) |

## What reviewers say

### WTFatLite

[App page](https://appshunter.io/ios/app/wtfatlite-with-physics-engine/id596265268)

Record your body weight and fat percentage with an engaging, physics-based interface. Visualize your progress over time with interactive graphs. Offers a fun alternative to traditional health tracking apps.

**Highlights:** Physics engine for interactive recording, Keyboard-free data entry, Weight and fat percentage tracking, Interactive data graphs, Data reset options

**Features:** macOS Compatibility

**In-app purchases:** none


### Undiet

[App page](https://appshunter.io/ios/app/undiet-weight-journey-tracker/id1490849895)

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Undiet Plus Monthly | $5.99 | per month |
| Undiet Plus Yearly | $34.99 | per year |


## Frequently asked questions

### Is WTFatLite free?

WTFatLite is free to download, with no in-app purchases.

### Is Undiet free?

Undiet is free to download, with in-app purchases available.

### Do WTFatLite or Undiet have ads?

WTFatLite shows ads; Undiet does not.

### Which is updated more often, WTFatLite or Undiet?

WTFatLite ships an update every 3 months, and Undiet weekly. Most recently, WTFatLite was updated on October 20, 2026 and Undiet on October 26, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*