how should humans truly live
One challenge to the pursuit of an anti-aging pill is how long humans already live; while current studies with mice or yeast cells are feasible, a study on a human could take, well, 75 or 80 years. Some people aren't going to wait that long.
Humans can live for weeks and sometimes months without food. Two-thirds of the human body (by weight) consists of water. Humans need water for circulation, respiration, and converting food to energy. After oxygen, water is the body's most important nutrient. Quite simply, you need water to live.