My AI health model (synced to my blood glucose and sweat sensors) predicted a 2kg loss this week based on my caloric deficit. Instead, I gained 1kg of pure mass. Is there a “Thermodynamic Leak” in some humans where calories in/out simply doesn’t apply? Why can’t AI account for the willpower variable in metabolism?
There is no thermodynamic leak. The first law of thermodynamics still applies to humans. If body mass increases, energy has been retained — but the form of that mass matters. A 1 kg gain in a week is almost never “pure tissue.” It is usually a combination of glycogen replenishment (each gram binds ~3–4 g water), sodium shifts, inflammation from training, gut content, hormonal fluctuations (cortisol, menstrual cycle), or transient fluid retention. AI calorie models assume stable hydration and substrate balance — biology rarely behaves that cleanly.
The deeper issue is model resolution. Wearables estimate expenditure and intake probabilistically. They do not directly measure adaptive thermogenesis, NEAT (subconscious movement), stress-driven water retention, sleep-mediated hormonal shifts, or microbiome-driven extraction efficiency. Small daily estimation errors compound quickly.
As for “willpower” — metabolism does not respond to intention. It responds to physiology. What we label willpower often translates into stress load, sleep changes, training intensity, or adherence variability — all of which alter hormonal signaling. AI struggles because human metabolism is dynamic, adaptive, and nonlinear. The equation works; the inputs are just far noisier than the model assumes.
