Which definition best describes thermic effect of food?

The thermic effect of food refers specifically to the energy expenditure associated with the processes of digestion, absorption, and metabolism of the nutrients present in the food consumed. When we eat, our bodies expend energy to break down the food, process its components, and utilize them for growth or energy. This energy expenditure accounts for a certain percentage of our total daily energy expenditure and varies depending on the type and amount of food consumed.

This concept highlights that not all the energy consumed through food is directly converted into usable energy for the body; a portion of it is used in the biochemical processes necessary for making that food available for use. This distinguishes it from other energy uses, such as energy for physical activity or the basal metabolic rate, which are separate aspects of total energy expenditure.