Clarifying Calories: A Universal Measure of Energy

Adaptive thermogenesis, or metabolic adaptation, involves changes in resting metabolic rate that exceed predictions based on shifts in body mass. This concept is essential for understanding energy expenditure, which includes various components like resting energy expenditure, activity-related energy expenditure, and diet-induced energy expenditure. A calorie, a fundamental unit measuring energy, behaves universally regardless of its source. While a lowercase calorie defines the energy required to heat one gram of water by one degree Celsius, food energy is typically quantified in kilocalories (Calories with an uppercase C), emphasizing the significantly greater energy content in food.