Were past generations healthier than today?

Not likely. Overall, while there may be factors of modern life which by themselves are less healthy, It appears that today people are generally healthier. Or, at the very least, have more information and more options available to achieve improved health if they choose.

Overall it depends on what criteria you are using to define healthier. From a purely subjective view of people living longer and over coming illness, then yes, modern man is far healthier than past generations.

How much of that health or long life depends purely on medicine and surgical advancement is going to be a highly debatable piece of the question (which some health conscious people would consider cheating since your health was not through natural food or exercise)

Another factor is pollution: Modern air and water quality are clearly worse, and the pollution constituents are different, than for distant past generations but it's also improving compared to the last few.

Another factor is knowledge; many drugs and poisons that people consumed regularly in the past, are now known to be bad for you and have either been removed from food supplies or at least heavily regulated (tobacco).

Another factor is nutrient density in foods. While it has been argued that modern grown foods (fruits, vegetables) do not have the same nutrient density as 100+ years ago, the simple fact that a wider range and mass volume of them are available may make up for (or potentially exceed) that limitation (also the availability of supplements in concentrated form)