As a young adult I moved from Toronto to Stockholm to start my studies in medicine. Although the values of Swedes and Canadians are similar, my first impressions revealed some visible differences in how people live their lives. People ate warm meals for lunch as well as dinner and processed food seemed less available. People biked or took public transport as downtown Stockholm is inaccessible for cars. At quick glance, people walking in the streets of Stockholm seemed one size smaller than in my home town of Toronto.

After 20 years of living abroad, I have experienced many differences in the way North Americans and Scandinavians live their lives. It came as no surprise to find that the obesity epidemic hit Scandinavia ten years after, and to a lesser extent, than in North America. Regardless of how much Toronto and Stockholm differ, both places have been subject to major environmental changes over the past five decades. The obesity epidemic has changed our view of what is considered normal, something that the clothing industry has caught on to. As people have become bigger, manufacturers created a larger range of sizes and altered labelling to accommodate them. A dress made to fit Marilyn Monroe’s waist would be between a size eight to twelve in 1958 but a size double zero today.

Although previous research suggested that genetic vulnerability had larger consequences after the onset of the obesity epidemic than before, our dataset provides convincing results, with a large sample size and range of years of assessments and ages. The findings were surprising. On average, genetic predisposition would make a 35-year old man of average height 3.9 kg heavier than his genetically protected peers in the 1960s. If the same man remained 35-years old but lived in Norway today, his vulnerable genes would make him more than 6.8 kg heavier. Additionally, both him and his peers would have gained an extra 7.1 kg simply as a result of living in our obesogenic environment. This man’s 13.9 kg excess weight is caused mostly by today’s unhealthy lifestyle, but also by how his genes interplay with the environment. 

The obese are often stigmatized for having unhealthy lifestyle choices. Acknowledging the importance of the obesogenic environment and its amplification of our genetic differences, can help destigmatise obesity. Perhaps it is time to shift our focus away from the individual and towards a healthier society.

Maria Brandkvist, PhD candidate at the Department of Public Health and Nursing, NTNU, Norwegian University of Science and Technology, Trondheim, Norway. 

Competing Interests: Please see research paper for further details.