The Science of Satiety: Why 200 Calories of Eggs is Not 200 Calories of Donuts

The "Calories In vs. Calories Out" (CICO) model is a fundamental law of thermodynamics. If you burn more than you consume, you lose weight. However, on a practical, human level, the source of those calories dictates whether your diet feels like a breeze or a constant battle against hunger. If you eat 200 calories of a glazed donut, you might feel hungry again in 30 minutes. If you eat 200 calories of boiled eggs, you might feel full for hours. Today, we’re using CalorieFinder data to explore the "Satiety Index" and the "Thermic Effect of Food" to show you why a calorie is not just a calorie. 1. The Thermic Effect of Food (TEF) Did you know that your body burns calories just by digesting food? This is known as the Thermic Effect of Food (TEF) . Different macronutrients require different amounts of energy to be broken down and processed: Protein: 20–30% of total calories consumed are burned during digestion. Carbohydrates: 5–10% are burned during digestion. Fats: …