Weight loss + training, principled

Log free.
Plan with intent.
Own your data.

Principled is a modular weight-loss and training tool built on one belief: accountability is enablement plus access — equip, never nag.

You don't need to be nagged — you need to be enabled. Motivation is yours to bring; our job is to remove every blocker between you and the work. Log in seconds. See the truth of your own data. Access it however you want. No guilt, no streak-shaming, no locking your numbers behind a paywall. Just the tools, and the truth. Compete if you want to. Bring your own AI if you're advanced. Your data is always yours.

The app is free, forever. Daily logging lives on your phone — no paywall on your own numbers.

Today
189.1
lbs · −9.3 since start
Logged
Breakfast380 kcal
Lunch620 kcal
Lower — Strength58 min

How it works

One product, three surfaces — each priced by what it actually is.

You never pay for access to your data. You pay for the amplified enablement we compute for you. That line is the whole model.

Free, forever
Mobile app

In-the-moment enablement

Fast capture, passive ingest, the right cue at the right time — plus full access to your data. The daily-habit surface.

  • Log workouts + meals in seconds
  • Your weight trend and history
  • Export your data anytime
  • iOS + Android
Paid
Web app

Amplified enablement

Planning, reports, meal planning, embedded AI. The big-screen controls for people who want to understand and plan, not just record.

  • AI reports on your real data
  • Forward-looking meal planning
  • Custom report builder
  • Billed on the web — no app-store cut
Free, advanced
MCP (BYOK)

Pure access

Bring your own AI. Point any model you choose at your own data through an open MCP endpoint. Openness as a feature.

  • Your data → any AI you choose
  • Bring your own key
  • Free for advanced users
  • No lock-in, ever
1Download the free app
2Log daily — build the habit
3Open the web to plan + understand

The promise

Your data is always yours.

We will never hold your numbers hostage. Export is free. The MCP endpoint is free. There is no version of Principled where seeing your own progress costs money. We win by being the most open tool in the category — not by locking you in.

Start logging — it's free

No guilt, no streak-shaming

Nudges are onboarding scaffolds that fade. We never accuse you of skipping. Motivation is yours to bring.

Access is never paywalled

Your data, export, and MCP are free forever. The paid line is only the compute we run for you.

Competition is opt-in

Social pressure is a module you choose, not a default that's tied to guilt. Off by default.

Open by design

Bring your own AI through MCP. Point any model at your own data. No lock-in is the point.

Just the tools, and the truth.

Bring the motivation. We'll remove the blockers.