People can grow very old and still remain in good health. Most of them will however, die long before their potential Biological Old Age is reached. You have to put aside the things as pestilence, violence, and pollution/environment and will find that despite the multitudes of experiments tried, and all the medical marvels of the last 100 years, the real potential of the human lifespan has not been lengthened at all. Still today, the oldest people on earth live traditionally in environments that are clean, clean air, good water, quality food, a tribal communities, low on stress, and within unspoiled nature. "Nature is not matter only, she is also spirit."
Why should that be? Perhaps the past can help to explain, let's take a look into some aspects of our history and then you can make up your own mind!

One of the oldest books we can use is the Bible. If you
look at the Old Testament you will find that Adam and
his six children lived for more than nine hundred years.
Methuselah is documented as a nine hundred and
ninety-six year old while Lamech was seven hundred
and seventy-seven years old and his first son reached
the age of one hundred and seventy-eight years old.
Noah lived for over nine hundred years, he was six
hundred years living on the Ark. Moses died at the age
of one hundred and twenty years.

The Sumerians, living in the same area, are another society who left us with a lot of records, this time in the form of baked clay documents (cuneiforms).
The Mesopotamians were the first known civilization that did start to
build Cities. Not only concerned with flood control and irrigation but
also with urban water supply and the creation of water highways for
there boots and barges. The Euphrates and Tigris are unpredictability
and vary a lot, a major problem. The system of canals, dikes, reservoirs more complex than most people do imagine. During 3000BC, every major Mesopotamian city was the center of a canal network reaching to the outermost limits of the city authority.

They recorded most of the reigns of the different Kings in the area and when we look at them we find:
Dynasty, Name, No. of Kings, Reign,

*The rule by kings stops at this point and power is transferred to the temple of Eanna at Uruk where the son of the high priest ruled for 324 years!

Ancient people explained the decrease and increase of the life span in the following terms:
* Time and space are aspects of the material world and when you
look at the stars you can see what is happening, new worlds get
born every day and others die out. Even our Earth and our Sun
have only a limited period of existence!

*Within the material world nothing is permanent, (flux) therefore human existence (body) is limited and there is no way in which you can deny or escape it.

* Spirituality, ideas and dreams do not contain matter and are not affected by Time. e)

The ancients people did associate Time with materialism, greed, corruption and destruction, saw it as important to reduce the impact of materialism on your life and lifestyle. Key to a long and healthy life are spirituality, consciousness being connected; the main point stressed that life to be sought by man, not in himself or in his own power, but from outside, from Him who is emphatically to Life. (God, Spirit, Nature, Conscious). 

*    This is one of the reasons why Buddha called the material world an illusion. Despite its powerful manifestation, its glamour and its glitter, it is all in vain.

    Expansion of consciousness and awareness could reduce the

effects of time in the material world and expand the maximum lifespan, a process  we call Transcendentalism.

Age or time associated with the mythic dying king, or "senex," who has lost touch withhis feelings, a Narcissi, out of touch with Eros/love, unable to maintain proper relations, creativity, compassion and a obstacle to growth and development, who out of fear of losing control and because of its own weakness,holds onto and becomes addicted to power and control. (Rules, regulations and control.) Based on the lie that happiness lies in the accumulation of stuff (especially expensive new stuff) and status to keeps our consumer culture functioning. The hard truth is that we are all slaves to a system that seeks to rob us of our joy, our time with loved ones and our freedom, while all the while feeding us propaganda that we are free and rewarding us with shiny possessions for our sacrifices.

Life extension and caloric restrictions

Artificial Rejuvenation
There is a big difference between fasting and the artificial rejuvenation of the body.
When it became clear that the maximum lifespan was decreasing
rapidly, people and their rulers started to look for other ways to extend life.
As far as we can tell, the Sumerian kings went to the temple and had to undergo a severe regime of food restriction with no solid foods, only lots of special vegetable juices. To help the king get through this difficult period they used special sedatives, resting him on a bench in the form of  a cross in a quiet room without light.
The food restriction would go on until most organs were reduced or
nearly gone. The liver for example was reduced to approximately 20% of its normal size. The process was so severe that halfway during his treatment all parasites, such as worms, would leave his body and flee, like rats do before a ship goes down. Needless to say that such a procedure is not without risks and takes a lot of knowledge! For this reason, only royalty and high priests would be treated in this way.
Fasting, and a simple way of living, were the guidelines for the common people and they too could greatly benefit from it.
Every important religion incorporated these guidelines for the benefit of their followers.
In modern times there is a big difference. People now are stimulated to consume, consume and consume….the more the better! At least that is what the big corporations/State try to get us to believe.