Because water is contained primarily in fat-free tissues - the muscles - the percentage of total body water can vary widely between individuals. Those with a high percent body fat can be as low as 40% total body water, while very lean individuals and athletes can attain 70%.
Water is the essential component of all vital fluids and the medium of transport in every biological exchange.
During a weight management program, it is essential to prevent an excessive decrease in lean mass – muscle – whilst the aim should be to maintain the required level of hydration through proper exercise and diet.
Women with 19% to 26% body fat are approximately 50% total body water, while men with 12% to 18% body fat are approximately 60% total body water.