Jesus Christ stayed up to 40 days without food; meanwhile, he was a human like you and me on earth. There are some prophets in my area who claim that they have stayed for 40 days too with food, but it was not just for competition but through a special assignment based on the Christian religion. Normal, there are some people who can fast for 10 days, while others can last more than that too.
I basically cannot stay that long without food because I don't know what will happen during the process. We all know that, scientifically, the body system of every individual is usually not the same as that of every other person.