Final answer:
Behavioral factors are considered the most influential single contributor to premature morbidity and mortality by many public health researchers. These factors, including diet and physical inactivity, are direct contributors to diseases like cardiovascular disorders and diabetes.
Step-by-step explanation:
The factor considered to be the most influential single contributor to premature morbidity and mortality, as identified by many public health researchers, is behavioral factors. These include a range of actions and choices such as diet, tobacco use, physical inactivity, and alcohol consumption. It is noted that these behavioral factors contribute significantly to metabolic syndrome, which is a major risk factor for diseases such as cardiovascular disorders and type 2 diabetes. Moreover, behaviors related to the consumption of sweetened beverages are highlighted as particularly significant contributors to this syndrome.
Socioeconomic status also plays a critical role, influencing access to resources and healthcare, but when considering single contributors, personal health behaviors show a direct and powerful impact on one's health outcomes.