People who drank sugary drinks daily had the biggest increase in visceral fat, researchers found.
Visceral fat is a harmful form of body fat that is stored around the abdominal cavity, wrapping around internal organs, including the liver, pancreas and intestines.
While all of us have some visceral fat, having too much of it can interfere with hormonal function and increase the risk of type 2 diabetes and heart disease, and some studies have even associated excess visceral fat with greater risk of Alzheimer's disease and some cancers.
According to Johns Hopkins Medicine, women with a waist of 40 inches or more and men with a waist of 35 inches or more are at greater risk of having health problems as a result of too much visceral fat.
For this latest study, Dr. Caroline Fox, a special volunteer at the National Institutes of Health (NIH), and colleagues set out to investigate how sugary drink consumption plays a role in the development of visceral fat.
The team recently published their findings in Circulation - a journal of the American Heart Association (AHA).
Daily sugary drink consumption poses greatest visceral fat increase
The researchers analyzed the data of 1,003 participants of an average age of 45 who were part of the Framingham Heart Study - an ongoing project supported by the National Heart, Lung and Blood Institute.
At the beginning and end of the 6-year follow-up period, participants underwent computed tomography (CT) scans to measure changes in visceral fat, and they also completed food questionnaires in which they detailed their consumption of sugar-sweetened drinks and diet soda.
Subjects were then allocated to one of four categories: non-drinkers of sugar-sweetened beverages, occasional drinkers (once a month or less than once weekly, frequent drinkers (once weekly or less than once daily) and those who consumed a sugary drink at least once daily.
They found that participants who consumed sugary drinks on a daily basis experienced the highest increase in visceral fat, at 852 cm3, compared with an increase of 658 cm3 for non-drinkers.
Occasional drinkers of sugary beverages experienced a 649 cm3 increase in visceral fat over the 6-year follow-up period, while frequent drinkers had a visceral fat increase of 707 cm3.
No association was found between diet soda consumption and visceral fat.
These findings persisted after accounting for possible confounders, including participants' age, gender, physical activity levels and body mass index (BMI), according to the team.
Study 'another piece of evidence that sugary drinks harm health'
The authors are unable to explain the biological mechanisms behind their findings, but study co-leader Dr. Jiantao Ma, postdoctoral fellow at the NIH, suggests that added sugars may play a role in insulin resistance, increasing the risk of type 2 diabetes and heart disease.
Despite the health risks associated with sugary drinks, their popularity remains high; in 2013, households in the US spent around $14.3 billion on the beverages, and according to the Centers for Disease Control and Prevention (CDC), almost half of us consume sugary drinks on any given day.
Dr. Fox says these findings provide further evidence that sugary drinks are bad for health:
"Our message to consumers is to follow the current dietary guidelines and to be mindful of how much sugar-sweetened beverages they drink. To policymakers, this study adds another piece of evidence to the growing body of research suggesting sugar-sweetened beverages may be harmful to our health."
The recently updated 2015-2020 Dietary Guidelines for Americans state that individuals should consume less than 10% of their daily calories from added sugars.
Recently, Medical News Today reported on a study revealing a 12% reduction in sugary drink sales in Mexico after a 10% tax on the beverages was introduced.