Society as a whole suffers when an individual falls ill. Nowadays, a disease can spread very quickly between people in the same community and even across national borders. If a single patient is not diagnosed and treated in time, many more people will be affected. In addition, the high cost of medical treatment a patient requires is usually paid by the government and society. A smoker who suffers from lung cancer, for example, is making other taxpayers pay for his habit. For these reasons, health is more than just a personal matter.
In the same way, good health benefits society as well as the individual. By keeping fit, a person is not only investing in his/her future, but also contributing to the overall productivity of society. That is the reason why many governments encourage their people to participate in sports as a way of boosting their health. Some people might argue that their freedom will be limited if their health is regarded as a public matter. However, I would like to point out that personal enjoyment should never be placed above public interests. Drug users, for example, are punished in any civilized society.
In conclusion, health is not an issue like seatbelts which affect only the individual. In an era when everybody is involved with everybody else, people should look after their health for the sake of society as well as themselves.