A Sugar Infusion in the 1970s May Explain the Current Obesity Epidemic

The findings of a recent study indicate that the U.S. obesity crisis of today can be explained as the accumulated effect of childhood exposure to a sugar infusion that began in 1970 coupled with continued consumption. The study was published in the journal Economics & Human Biology.

In approximately two generations, obesity has become a global epidemic, with rates tripling between 1975 and 2016 – when more than 650 million adults were obese, accounting for 13% of the world’s adult population. In the U.S. the most expeditious increase in obesity occurred over the past 30 years, when the national obesity rate almost doubled from 1990 to 2016.

While there are many contributing factors to the obesity epidemic, such as age and socioeconomic status, a chief contributor can be traced to 1970, when high-fructose corn syrup (HFCS) was introduced into processed foods and sugar-sweetened beverages (SSBs). Although this change has been readily observed, as the researchers note, until now the time lag has remained unexplained. They postulated that the obesity spike can be explained as an accumulated effect of early exposure combined with continued use, since childhood obesity often predicts obesity in adulthood.

To conduct this study, the researchers formulated a sugar-driven model designed to replicate three different aspects of the national obesity trend: the overall increase of adult obesity since 1970; an age profile of obesity for a recent year; and the change of obesity rates by pre-adult age groups since 1990. Subsequently, they modeled the obesity rate for each age group as its obesity rate in the previous year plus a log-odds function of the average excess sugar intake in the current year. The model generated an environment of the 46 calendar years in focus (1971 to 2016) versus life ages, from age 2 through age 75. In this model, which was developed to replicate generational lag time, obesity in a given year correlated to a certain age group was calculated as a function of obesity for the same cohort in the previous year when that age group was younger.

The Model Exhibited Efficacy

According to the results, the model was able to reproduce the average U.S. obesity increase through calendar years and across age profiles, showing an increase in adult obesity since 1990. Moreover, using similar parameters, the model simultaneously duplicated the age-obesity curve in 2015, depicting most aspects of the age profile except for ages 75 and over – a cohort who grew before the sugar infusion of the early 1970s. The model also replicated a decrease in obesity among children beginning in the late 1990s, which links to decline in excess sugar production around that time.

The researchers wrote in their conclusion that their model “supports the perspective that the rise in U.S. adult obesity after 1990 was a generation-delayed effect of the increase in excess sugar calories consumed among children of the 1970s and 1980s.”