The phrase "main protein source" refers to a food or dietary component that provides the majority, or most significant amount, of an individual's daily protein intake. Proteins are essential macronutrients that play numerous roles in the body, including building and repairing tissues, enzyme production, hormone synthesis, and energy metabolism. Adequate consumption of proteins is necessary for maintaining overall health and well-being. The "main protein source" can vary depending on an individual's dietary preferences or cultural practices, but generally includes foods such as meat, poultry, fish, eggs, dairy products, legumes, nuts, and seeds.