If sitting is the new smoking, should employers be held liable?

Researchers have linked sitting for long periods of time to a number of health issues, including increased high blood pressure, high blood sugar, excess body fat and cholesterol. They also warn that prolonged sitting increases the risk of cardiovascular problems and cancer. What does this mean for organizations whose employees end up sitting for at least eight hours a day? Should they be held liable for harms caused to employees in sedentary workplaces?