summary - Part II of the classic Keys metabolic-ward series: 227 healthy men across 19 controlled comparisons had dietary cholesterol varied from 50 to 1450 mg/day with all other diet variables held constant. Serum total cholesterol (pre-dated routine LDL fractionation) rose with dietary cholesterol dose but with strongly diminishing returns at higher intakes, fit by a square-root term - the cholesterol component of the Keys equation - rather than a linear one.
relevance_note - The founding dose-response quantification of dietary cholesterol’s effect on serum cholesterol; most later “cholesterol raises LDL” claims and prediction equations trace back to this series.