A lack of protein can negatively affect muscle maintenance by hindering repair and growth processes. Muscles require protein for recovery after exercise, and insufficient intake can lead to muscle loss, reduced strength, and increased fatigue. This condition, often referred to as muscle wasting, can impair overall physical performance and prolong recovery times. Additionally, inadequate protein can impact the synthesis of hormones and enzymes necessary for various bodily functions. Therefore, ensuring an adequate protein intake through food sources like lean meats, beans, and dairy is crucial for sustaining muscle health.