The Causes and Complexity of Obesity

April 29, 2015 | 3:24 pm
Lindsey Haynes-Maslow
Former contributor

Unfortunately, there is no straightforward and easy way to explain what causes obesity. The Socio-Ecological Model (SEM) of Health attempts to address the question of how people become obese. The basic premise of SEM is that becoming overweight or obese is very complex and combines a number of factors that can impact health outcomes. Most SEMs describe these factors as individual (genetics and personal health beliefs); inter-personal (social networks and supports); organizational (rules, regulation, programs, and practices), community (environmental characteristics); and policy (public policies and systems affecting distribution of power and resources). This post focuses more heavily on the diet aspect in the SEM.

Individual Level

Individual health behaviors both shape and are shaped by the environment. At the individual level, risk factors for weight gain can include age, gender, dietary intake, and physical activity levels. Individual characteristics that influence behavior, such as knowledge, attitudes, beliefs, and personality traits, can affect diet and food consumption choices.


*Adapted from the NHLBI Workshop: Predictors of Obesity, Weight Gain, Diet, and Physical Activity; August 2004, Bethesda MD

Interpersonal Level

At the interpersonal level, individuals’ weight is influenced by their social environment, including home and family life, social networks and supports, and social norms. Social norms influencing individual food consumption include eating out, eating as a social activity, and weekend eating.

Currently, more than 50% of the money Americans spend on food is for foods consumed outside the home. In general, eating has become a social activity; individuals eat out with friends after work, school, birthdays and other special occasions. Unfortunately, multiple studies have shown that people consume more calories at restaurants when in groups. Additionally, research has shown that individuals tend to consume more calories during the weekends. On average, American adults consume an extra 115 calories per day during the weekend—Friday, Saturday, and Sunday night, compared to Monday through Thursday.

Organizational Level

The organizational level includes schools and worksites. Individuals are affected by rules, regulations, programs and practices that these organizations implement and encourage.  Organizations’ structures and processes can affect individual weight either positively or negatively.  The availability of certain foods at a school, worksites, or health care settings can impact food consumption. Having vending machines with sodas and other high-calorie beverages, as well as high-fat and high-calorie-content food, could negatively impact an individual’s weight, whereas having a weekly farmer’s market or access to healthier snack foods and beverages might positively influence food consumption choices.

Community Level

In simplest terms, the community level is where individuals live, work, and play. The Centers for Disease Control and Prevention states that “communities are like a large organization, able to make changes to policy and the environment to give residents the best possible access to healthful foods.” Much of my research to date has focused on the community level.  This includes access to affordable, high-quality, healthy foods.

Shifting Our Focus

Some public health professionals argue that individual behaviors only affect 50% of an individual’s health. The recognition that being overweight or obese is not entirely an individual’s fault has shifted the public health focus from individual responsibility to community, organization, and public policy levels that can address weight.