Obesity has definitely gone global. Although it will be difficult to prove using scientific methods, which can be pretty blunt for this type of investigation, I have no doubt that the epidemic started in the US around 1950-1960. This is the era that saw the rise of the junk food industry, mechanized transport, more stress, increasing social disconnection, more aggressive marketing, and changed consumer habits. But the main change was undoubtedly the junk food invasion.
It did not happen overnight, and the epidemic did not get its breakthrough until around 1980. Like a snowball rolling down the hill, the epidemic was now fuelled even more by other changes to society. Both Reagan and Thatcher, for example, started to gradually dismantle the welfare system during this period, meaning that poor people got pushed over the edge financially and had no choice but to eat cheap junk food. The rise and rise of junk food marketing also reached new levels through TV, and use of colorful images and messages. We were told to consume and consume we did.
If you walk around major cities in Europe and the US today it is quite staggering how much food, transport, lifestyle, family, working hours, stress, etc has occurred during the decades when the epidemic really took off. There has also been a large disconnect from nature and a more balanced lifestyle through massive urbanization and who knows how much toxicity we are exposed to today in the cities compared to the days before the epidemic as a result of pollution, pesticides, steroids and antibiotics in our food. Children have also increasingly been growing up in environments where they see less and less of their parents, who both work full time to pay their mortgage. The increased stress levels is certainly a major factor that fuels the the epidemic more and more.
We are suckers for these types of very gradual changes, and the prize for this lack of vigilance is that one day we find ourselves in a hole that we struggle to get out of. And as always in epidemiology, it is the combination of causal factors that tip us over the edge. And those environmental changes I have mentioned as causal obviously also play a very prominent role in many other health epidemics, such as diabetes, cancer, heart disease, and depression. How much more of this will it take before we take action and get back to a more balanced lifestyle?