I am developing the Lipid Encephalisation and Mismatch Hypothesis (LEHM) - a theoretical framework proposing that progressive lipid dietary transitions across the Homo lineage drove successive APOE allele innovations enabling hominin encephalisation, and that the modern dietary environment constitutes a two-hit mismatch explaining the disproportionate neuroinflammatory burden in APOE4 carriers. LEMH integrates the fat hunter work of Ben-Dor and Barkai, Crawfords DHA-brain hypothesis, and the APOE allele transition mechanism into a unified evolutionary framework with direct clinical applications. A systematic review and dietary protocol paper are in preparation.