If you would consider the process of digestion as a mechanism to breakdown complex substances into smaller and simpler one then it would be a purely endothermic process as the breakdown of complex compounds like proteins, carbohydrates and fats into peptides and amino-acids, mono-saccharides and MAG and fatty acids respectively requires bond breaking with the help of various enzymes and to break bonds energy is required. But if you would consider digestion as a process to provide energy (a basic, entry level and lower standard concept) it could be considered exothermic as energy would have been released, but for the fact the process of oxidation resulting in release of energy by electron transport system occurs in mitochondria and and that process is known as respiration, it would be not so correct.

Introduction:
Digestion is the process of breaking down food into smaller molecules that can be absorbed and utilized by the body. It involves several chemical and physical processes that occur in the digestive system. The question of whether digestion is an exothermic or endothermic reaction is a common one.

Exothermic Reaction:
An exothermic reaction is a chemical reaction that releases energy in the form of heat, light, or sound. During an exothermic reaction, the reactants have more energy than the products. The excess energy is released into the surroundings.

Endothermic Reaction:
An endothermic reaction is a chemical reaction that absorbs energy from the surroundings. During an endothermic reaction, the products have more energy than the reactants. The energy is absorbed from the surroundings, usually in the form of heat.

Is Digestion Exothermic or Endothermic?
Digestion is an exothermic reaction. The breakdown of food molecules releases energy that can be used by the body. This energy is in the form of ATP (adenosine triphosphate), which is the primary source of energy for cellular processes in the body.

Examples of Exothermic Reactions in Digestion:
1. Hydrolysis: Hydrolysis is the process of breaking down large molecules into smaller molecules by adding water. This process is exothermic because it releases energy when the bonds between the molecules are broken. For example, when the bond between glucose molecules in starch is broken, energy is released.
2. Enzymatic Reactions: Enzymes are proteins that catalyze chemical reactions in the body. Many of these reactions are exothermic because they release energy. For example, the breakdown of protein molecules into amino acids releases energy that can be used by the body.

Conclusion:
In summary, digestion is an exothermic reaction. The breakdown of food molecules releases energy that can be used by the body. This energy is in the form of ATP, which is the primary source of energy for cellular processes in the body. Many of the chemical and physical processes involved in digestion are exothermic, including hydrolysis and enzymatic reactions.