The Reconciliation

Can calories in and out, plus protein, account for what the scan measured? Partly.

§ 1.1 — Fat reconciles

Over 30 logged days the cumulative deficit implies -11 lb of fat. DEXA measured -10 lb, a gap of only 1.40 lb. For fat, the energy-balance model holds up.

§ 1.2 — Lean does not

The same window shows + 8.40 lb lean, which energy balance can't produce. You don't build 8 lb of muscle out of a deficit. Protein was ample ( 1.83 g/kg, inside the ACSM hypertrophy range), so some real newbie muscle is plausible, but the size of the change points to glycogen and hydration water, quantified on the overview.

Variables on this page

• Cumulative net energy — Σ (intake − TDEE) over the 30 logged days; negative is a deficit.
• Implied fat Δ — cumulative_net_kcal / 3500, the fat change the deficit predicts (3,500 kcal ≈ 1 lb of fat).
• Observed fat Δ — what DEXA actually measured.
• Gap — observed − implied; small means the energy-balance model held.

What this does and doesn't show

It shows that a first-order energy-balance model predicts the fat change well (within 1.4 lb) and explains none of the lean change, which is what hands the lean question over to the uncertainty decomposition. The 3,500 kcal/lb figure is an approximation (real tissue change mixes fat, water, and lean, and TDEE adapts over time), so read the gap as consistent rather than proven. See methods.