Proof Engine Verification (PARTIALLY VERIFIED): Cold plunges and ice baths significantly boost metabolism via brown fat activation and aid long-term fat loss.

Automated fact-verification of the claim: "Cold plunges and ice baths significantly boost metabolism via brown fat activation and aid long-term fat loss." Verdict: PARTIALLY VERIFIED Key Findings SC1 (BAT activation): CONFIRMED — 3 independent peer-reviewed sources (J Clin Invest 2012, J Clin Invest 2013, Int J Mol Sci 2023) confirm cold exposure activates brown adipose tissue (BAT) in humans, meeting the threshold of 2 verified sources. SC2 (metabolic boost): CONFIRMED — 3 independent peer-reviewed sources (Redox Biol 2017, Endocrine Rev 2020, Front Endocrinol 2018) confirm BAT activation increases resting metabolic rate and energy expenditure, meeting the threshold of 2 verified sources. However, reviewers consistently characterize the whole-body effect as modest ("at the lower end of clinically relevant"), so "significantly" is an overstatement. SC3 (long-term fat loss): NOT MET — Only 1 hedged supporting source found (Esperland et al. 2022, "CWI seems to reduce adipose tissue"); threshold requires 2. Three independent reviews explicitly state no consistent fat or weight loss has been demonstrated from cold exposure in humans. Compound verdict: PARTIALLY VERIFIED — SC1 and SC2 are supported; SC3 is not. The claim's chain of causation (cold → BAT → metabolism → fat loss) breaks at the final link. Files proof.py — Re-runnable Python verification script proof.md — Structured proof report proof_audit.md — Full verification audit trail proof_narrative.md — Plain-language summary proof.json — Machine-readable structured data Generated by Proof Engine v1.3.1.