Human beings are part of nature and natural things are best for their health and wellbeing. What comes in packet and manufactured in factory, if consumed on a regular basis may do great harm over a period of time. Here is the outline of factors that contribute to disease. If you take care you can lead a healthy life for 100 years or more. Disease creation is a complex process and each body is unique/different. It may take some years before disease starts manifesting.
Body Mind complex is a wonderful machine created by nature, it can take lot of abuse BUT not for ever.