Alcholol and smoking are not modern inventions. Smoking was introduced when America was discovered, and alcohol has been consumed for thousands of years, often in much greater quantities than today. The reason why there is a tax on alcohol is because when people in Britian worked out how to make cheap gin in the 1700s, they all got drunk and the population actually started declining! So the government had to make alcohol more expensive to stop people dinking so much.
Pesticides are not really that bad either. They may have some health effects, but imagine if people stopped using them? Food production would plummet and millions of people would starve to death.
Overeating is a modern problem, but it is caused by the overabundance of wealth. Before overeating there was under eating, which is much worse for your body, just not as morally reprehensible.
See above. Before modern medicine (and therefore animal testing) we had smallpox. We had plague. We had polio and we had many other horrible diseases. Now smallpox only exists in labs and munitions stores, and the others have been eliminated from the western world, with significant progress in developing countries as well. Before modern medicine, most people lived in horrible, filthy conditions, and they thought that they only way they could cure diseases was by butchering Jews!