The thermic effect of food (TEF) refers to the increase in energy expenditure above the resting metabolic rate after eating. This effect occurs because the body uses energy to digest, absorb, and metabolize nutrients from the food consumed. Different types of food have varying TEF values, with proteins generally requiring more energy to process than carbohydrates or fats. TEF typically accounts for about 10% of total daily energy expenditure. Factors such as the composition of the meal, individual metabolism, and overall diet can influence the magnitude of the thermic effect. Understanding TEF can help in managing weight and optimizing nutrition for better health.