People are living longer. Why?

Personally, I contend that people are living longer because they are taking better care of themselves. For example, my grandfather is eighty. When he was younger, he used to smoke and drink a lot. Also, he never ate very well. Then, when he was fifty, he had heart attack. He was in the hospital for a long time. The doctor told him he should stop smoking and drinking, and start eating better. That’s what my grandfather did. Now, he doesn’t drink or smoke anymore. Also, he eats lots of healthy food like salads and fish, and he exercises every day. As a result, he feels much better than before and has lots more energy. By changing his lifestyle, my grandfather is definitely going to live longer because he is taking better care of himself.