Our forefathers lived for a hundred years or close to hundred years of age and I agree with the author that our forefathers had good food to eat, besides it, they didn't spend luxurious life as well. They did not have serious diseases too. They used to do physical work as well.
Let alone food we don't get fresh air also. Tensions and depression are more common now. We have different mental disorder and diseases which our forefathers had never heard. They lived a very simple life.
No life without Sun
Knowledge is power.
Medical facilities increased and new medicines and ways of treatment are coming. Now there is a cure for very difficult problems are also there. So if we have good habits, we can live for a minimum of 80 years.There is no doubt. More than 90% of the people will be living for more than 80 years I feel. Further, with modern technics and medicines coming into usage the life span will definitely increase.
Take proper food, daily do some exercise, don't indulge in bad habits and follow good practices of life. Then one can live for more than 80 years.
Thoughts exchanged is knowledge gained.