The short version
Nexus is the lowest-effort way to log: one message, in the ChatGPT or Claude chat you already have open, by text or voice or photo. Every other app on this list makes you open a separate app, and most of them charge extra for photo and voice logging. Nexus includes both, free.
Side by side
| Where you log | Photo logging | Voice logging | Describe a meal in words | Barcode | Price (US) | |
|---|---|---|---|---|---|---|
| Nexus | Inside ChatGPT or Claude | Yes, included | Yes: dictation and ChatGPT voice | Yes, that's the main way | Not needed: photo the label | Free |
| MyFitnessPal | Its own app | Meal Scan, Premium | Voice Log, Premium | Via Voice Log, Premium | Premium | $19.99/month or $79.99/year |
| Lose It! | Its own app | Snap It, Premium | AI Voice, Premium | Not confirmed | Premium | Free tier; Premium in-app (App Store lists $9.99–$79.99) |
| Cal AI | Its own app | Yes, subscription | Not confirmed | Yes, subscription | Yes, subscription | Subscription required |
| MacroFactor | Its own app | Yes | Yes, via Describe | Yes (Describe) | Yes | No free tier; $11.99/month or $71.99/year |
| Cronometer | Its own app | Photo Log, Gold | Voice Log, Gold | Yes, Gold | Free | Free tier; Gold $10.99/month or $59.99/year |
| Amy Food Journal | Its own app; also a ChatGPT app | Not confirmed | Not confirmed | Yes, the main way | Not confirmed | No free tier; $9.99/month |
Sources: MyFitnessPal Premium, Lose It! on the App Store, Cal AI, MacroFactor on the App Store, Cronometer Gold, Amy pricing. "Not confirmed" means we could not find it on the app's own pages.
What about MyFitnessPal in ChatGPT?
MyFitnessPal has a ChatGPT plugin. Its listing describes it as meal plans, recipes and nutrition guidance. Logging still happens in the MyFitnessPal app. Nexus is the log itself: what you tell ChatGPT is saved, shown as a card, and readable later from ChatGPT or Claude.
Looking to switch? See Nexus as a MyFitnessPal alternative.
Comparing trackers that work inside ChatGPT and Claude? See the best calorie trackers for ChatGPT and Claude.
Why "inside the chat" matters
The hardest part of calorie tracking is doing it on day 30. A separate app is one more thing to open, and every open is a chance to skip. Nexus rides on a habit you already have. You are in ChatGPT or Claude anyway; logging lunch is one more message.
It also means the assistant that logs your food can use it. "I have 600 calories left, what should dinner be?" gets an answer built from what you actually ate today.
"But what about barcodes?"
A barcode is a lookup key for numbers copied from the package label. ChatGPT and Claude read the label itself from a photo, so you get the source numbers instead of a database copy, with no Premium plan. More in you don't need a barcode scanner anymore.
"What about restaurant food?"
Photograph the bill. The assistant reads what you ordered, looks up the restaurant's published nutrition and logs each item. No calorie app does this, because none of them has a frontier model reading the receipt. See snap the bill, log the meal.
It gets better on its own
The estimating in Nexus is done by ChatGPT and Claude. Every time OpenAI or Anthropic ship a better model, Nexus reads plates, labels and receipts better that same day. A standalone calorie app has to build all of that itself.
Try before you switch
The Nexus sandbox runs the real card and tools with no account. Log a meal, edit it on the card, read it back. Then add Nexus to ChatGPT or Claude.