Final answer:
Protein is the nutrient most abundantly found in animal food products, serving as an essential macronutrient necessary for the body's growth, repair, and maintenance.
Step-by-step explanation:
The nutrient found most abundantly in animal food products is protein. Proteins are essential macronutrients that the body needs for growth, repair, and the maintenance of good health. Compared to carbohydrates and fats which also provide energy, proteins have a higher energy density. Furthermore, higher levels of proteins in the diet can help to increase the absorption of another nutrient, calcium. This is important because, unlike some vitamins and minerals which are micronutrients needed in much smaller amounts, proteins must be consumed in large quantities as they are crucial for the structure and function of the body's cells.