Sugar-link to obesity

The high obesity rates currently observed among adults in the US may have been due to dietary changes that took place decades ago, according to a study.

The research, published in the journal Economics and Human Biology, noted that while many health studies identified sugar as a major factor in the obesity epidemic, its consumption in the US began to decline in the late 1990s, even when the obesity rates continued to rise well into the 2010s.

The researchers, from the University of Tennessee (UT) in the US, said that the changes we see now in adult obesity rates may have started decades ago with high-sugar diets in childhood, when those grown-ups were children.

"While most public health studies focus on current behaviors and diets, we took a novel approach and looked at how the diets we consumed in our childhood affect obesity levels now that we are adults," said Alex Bentley, lead researcher of the study from UT.

The researchers noted that In Tennessee alone, the adult obesity rate more than tripled, from about 11 per cent in 1990 to almost 35 per cent in 2016.

According to the researchers, by 2016, nearly 40 percent of all adults in the US, which was about 93 million people, were affected by obesity.

Excess sugar consumption, particularly those in sugar-sweetened beverages, is a well-known contributor to both childhood and adult obesity, the researchers said.

"Since the 1970s, many available infant foods have been extremely high in sugar," said Hillary Fouts, coauthor of the study from UT.

Fouts added that sugar consumption during pregnancy was known to cause an increase in fat cells in children.

"Up to this point, no studies had explicitly explored the temporal delay between increased sugar consumption and rising obesity rates," said Damian Ruck co-author of the study.

The research team modelled the surge in US adult obesity since the 1990s as a measure of the increased excess sugar consumption observed among children in the 1970s and 1980s.

They tested their model using the national obesity data collected between 2004 and 1990 by the Centers for Disease Control and Prevention in the US.

The researchers could also capture how the obesity rates differed between age groups among children and teenagers.

"Our results suggest that the dietary habits learned by children 30 or 40 years ago could explain the adult obesity crisis that emerged years later," said Ruck.

The study noted that before 2000, a large portion of the sugar increase was from high fructose corn syrup (HFCS), which quickly become the main sweetener in soft drinks and a common ingredient in processed foods after 1970.

In 1999, each person in the US consumed on average around 27 kilogrammes (Kg) of HFCS per year, and more than 400 calories per day in total excess sugars, the researchers said.

But according to the study, sugar consumption in the US has declined since 2000.

Bentley said that 2016 was the peak year for adult obesity which is one generation after the peak in excess sugar consumption.