they reset themselves to their DNA pattern by prolonged fasting
That's nonsense. It may make sense to you, but it won't make sense to anyone else without explaining what "reset themselves to their DNA pattern" means and how that is brought about by prolonged fasting.
Neither science nor the Bible gives us any clues as to how the first people lived so long.
The ideal age is between 17 an 20 years. A person is at his healthy DNA pattern at that age. By the time he is 80 or 90, even though he has the same basic DNA, it isn't expressing itself the same as at 20. Fasting causes the body to gobble up bad and crippled DNA for food, and only the healthy DNA remains... back to 20.
The early people lived as long as they did because the whole Earth system was not corrupted in depth as it is today. Consider that the North Polar areas were warm, as can be seen by the mammoths that have been dug out of the ice in Siberia, with flesh almost fresh enough to eat, and with freshly cropped grass still in their mouths and stomachs.
Further, frequent fasting is a practice that keeps people healthier than if they didn't. When Jesus fasted, He was wildly in prayer to His Father to be saved from death. He was heard because of His reverent submission. How many other fasting people even understand how to pray to God, but if they did, they would realize that Jesus has already taken the punishment for sin, and we can ask, knowing that we will get what we asked for, because Jesus said so. "Man doesn not live on bread alone, but by every word that proceeds out of the mouth of God.
So, we actually have a chance to live for loads of years longer than we normally think... maybe hundreds of years.
It's doubtful. Prolonged fasting can lead to death, and many people fast regularly but they don't live longer than anyone else.
Doubtful? Doubt is simply faith that the thing you ask for won't happen. There are prisoners who have gone on 2-month hunger fasts and lived.
With faith you can move mountains, and nothing will be impossible for you, if you have the correct faith. So, don't be doubtful, because "he who doubts is like a wave of the sea, tossed this way and that. Such a person shouldn't expect to receive anything from God."
Actually it's mostly about the spiritual gains. The less you feed the flesh the more aware or active the Spirit becomes. And you will see visions and recieve messages from above. The 40 could signify the 40 days of fasting by Moses on Mount Sanai while receiving the commandments and other messages from the CREATOR. In Acts of the Apostles Peter fell into trance while he was hungry or fasting. Someone was once told by the CREATOR that fasting (while feeding with the Word of GOD) will make him be as a wave or light(wave was actually shown to the person). He was further told that the enemy uses gluttony to weigh people down, probably spiritually. Try feeding yourself with the Word of GOD while fasting and you could have a life changing experience.
Besides, if you are in the presence of the CREATOR, your thirst for water and hunger for food will completely disappear. This is actually from experience.
When Jesus washed the disciples feet, note that Peter out of humility didn't want to be washed. Then when Jesus said it was a requirement to be His disciple, Peter wanted His face and hands washed, as well.
Peter was looking at the mystical and a 'holier than thou' attitude. Jesus was simply looking at the practical, and teaching His disciples to serve one another.
There is numerology all over the place. In fact we don't understand it. But a 40-day fast has results that are not numerological, or are in addition to the numerology. That's what we are looking for.
If a person has enough faith, he doesn't need 'tricks' to become youthful, again. But notice what Jesus often did. He used some earthly elements to heal, and He said, "According to your faith will it be done for you." We need the trick of something physical to bolster our weak faith... even though Jesus didn't for Himself.