Volumetrics diet focuses on high-volume, low-calorie foods to feel full while consuming fewer calories. It categorises foods into four types: Category 1 (very low-calorie foods like fruits and vegetables), Category 2 (low-calorie foods like whole grains & lean protein), Category 3 (moderate-calorie foods) and Category 4 (high-calorie foods eaten sparingly). It promotes long-term healthy eating.