Final answer:
The best explanation for the need for increased protein intake by athletes is the increased need for tissue repair and muscle recovery after vigorous exercise. Athletes generally require more protein, as it is crucial for muscle maintenance, growth, recovery, and metabolic reactions during exercise. High-quality protein is important, and vegetarians may need more protein due to lower digestibility and differing amino acid profiles of plant proteins.
Step-by-step explanation:
The need for increased protein intake by athletes is best explained by the increased need for tissue repair. During exercise, especially with resistance training or intense physical activity, muscle fibers undergo stress and microdamage, necessitating repair and growth. As a result, the body requires more protein to support these processes, as proteins are the building blocks of muscle tissue. Additionally, protein plays a vital role in metabolic reactions necessary for energy production during exercise. Athletes, therefore, often require higher quantities of protein, ranging from 1.2 to 2.0 g/kg/day, to ensure optimal muscle maintenance, growth, and recovery.
It is also important to note the significance of protein quality. High-quality proteins, such as those found in animal products, generally provide a more complete amino acid profile which is crucial for the body's needs. Vegetarian athletes may need to consume higher amounts of protein to compensate for the lower digestibility and different amino acid profiles of plant-based proteins. Moreover, energy requirements for athletes are higher, and since energy needs influence macronutrients intake, higher protein consumption is often necessary to meet these elevated energy demands.
Micronutrients, including iron, calcium, vitamin D, and antioxidants, are also crucial for athletes, as they play essential roles in energy metabolism, oxygen delivery, and protecting against oxidative damage. Although general micronutrient requirements do not differ significantly from the non-athletic population, because athletes consume more calories to meet their energy demands, they typically intake more vitamins and minerals through their diet.