Calorie density is calories per gram of food. Research by Rolls found low-density foods (vegetables, fruits) fill your stomach and trigger stretch receptors before excessive energy intake, while high-density foods (oils, chips) pack hundreds of calories into small volumes. Your satiety system evolved to regulate volume, not calories. Low-density eating aligns ancient signals with modern needs.
This companion covers the numbers, why density matters, the practical application, and volumetric eating. (4 min read)