It is observed that constipation is common among people in the western countries, who eat meat and?

To get a scientific answer you would have to get all the variables to the units that has been observed and run a regression analysis for example with people in western countries that eat meat and does not have constipation problems. I live in a western country and I eat a lot of red meat, chicken, fish and drinks 1-2 liters of milk a day and I have no problem with constipation because I also eat very high fiber rich cereals combined with nuts.

I would have to guess that people with constipation also have very unhealthy lifestyle such as watching TV or using computer all afternoon/evening without working out or recreational hobbies. Also drinking/partying, smoking may also be contributing factors.