Good statistics were given by the IRA militants' hunger strike in 1981 in the British prison Maze. Fastest death on day 46. The most recent for 73 days. On average, most died around the 60-day mark.
A total of 23 people starved, 10 died, the rest stopped.
The most tenacious stopped at 71 days and survived.
Depends on many reasons. Internal: age, health status, individual characteristics of the body. External: climatic conditions and physical activity. An infant or person with severe cardiovascular disease without water can die in 30-40 hours. The same will happen to the average person who tries to walk in the afternoon on some Sahara or Death Valley. It is believed that the average person will survive without water for 5-7 days if he is at a temperature of 20C and a humidity of 80% without doing any work. There were isolated cases when this period reached 10 days - but irreversible changes in internal organs inevitably occurred there.
Without food, a healthy middle-aged person without physical exertion and under favorable weather conditions can withstand 30-45 days. But here much more often longer periods were recorded - and survived 60 and even 75. But getting out of the state of prolonged starvation is also not easy and not quick.