The most abundant macronutrient in the body is water. Water constitutes about 60% of the human body and plays a critical role in maintaining physiological functions. It is essential for regulating body temperature, transporting nutrients, and facilitating biochemical reactions. Beyond that, water acts as a lubricant and shock absorber for joints and organs, supports cellular processes, and helps in waste elimination. Thus, proper hydration is vital for overall health and well-being.