BodyTrackLog: Hard Data for Physical Protocols

Physical progress demands accurate telemetry.

Most people guess their body fat percentage in the mirror, adjust their macros on a whim, and wonder why the scale refuses to move after 12 weeks. The reality is brutal: weight is a terrible proxy for tissue change. You can lose 2kg on the scale but if 1.5kg of it was water and 0.5kg was muscle, you are technically fatter.

BodyTrackLog exists for people who treat their physical protocol like a systems engineering problem. We compile the definitive formulas, testing protocols, and accuracy boundaries for body composition analysis.

The Baseline: What is Body Composition?

Body composition divides your total weight into two main compartments: Fat Mass (FM) and Fat-Free Mass (FFM).

• Fat Mass includes essential fat (stored in marrow, organs, central nervous system) and non-essential storage fat (adipose tissue).
• Fat-Free Mass includes muscle, bone, water, connective tissue, and organs.

If you are 80kg and 15% body fat, you carry 12kg of fat and 68kg of fat-free mass. Tracking the ratio between these compartments is the only way to know if your training block or diet phase was actually successful.

Why Smart Scales Are Unreliable

Consumer bioelectrical impedance (BIA) scales send a weak electrical current through your feet. Muscle, containing mostly water, conducts the current easily. Fat resists it.

The core issue: BIA measures resistance, not fat.

If you drink a liter of water, step on a BIA scale, and take a reading, it will register lower body fat because your total body water increased. If you exercise and sweat, depleting cellular hydration, the scale will read higher body fat, even though you just burned calories.

To track body composition accurately, you must standardise your environment or switch to methods measuring physical dimensions (calipers/tape) or clinical imaging (DEXA).