Selecting the optimal body composition method | Notion

Why multiple body composition methods?

Some users (especially bodybuilders: very low body fat + high muscle mass) need a different method for best accuracy.

Recommended Methods

Use Case	Method
Most users (default)	`coco2`
Legacy users (transitioning)	`coco_bri`
Confirmed bodybuilders	`army_athlete`
Users want comparison	Use `PATCH` to apply multiple methods

Integration Guidance

Default: Use coco2 for all new scans.
Athlete Mode: Offer army_athlete for bodybuilding physiques. Either:
1. Auto-select via heuristic/proxy signals (training >10 h/week, very low body fat, low resting HR).
2. Allow manual selection (profile, settings, or scan result feedback if not happy with body fat % number).

SDK / API Setup

Method set per scan via bodyfatMethod when creating the scan via POST /scans/.
PATCH existing scans to apply other methods and compare results via PATCH /scans/{scan_id}/bodyfat with body { "bodyfatMethod": "Choose Your Method" }

Key Transitions

Partners on coco_bri → switch to coco2 (expect small body fat % metric shifts, on average ±2%). Have a comms plan in place to handle user feedback.
Old methods (coco, tina_fit, extended_navy_thinboost) are legacy and will deprecated in the near future.

Body Composition: Comprehensive Documentation