The different ways sugary drinks and foods are processed by the body could be responsible for the distinction, researchers believe.
Scientists monitored a group of adults over the age of 45 over a six-year period.
They found participants who drank at least 24 ounces of sugary beverage daily were twice as likely to die from heart disease as those consuming less than one ounce.
The findings only established an association and did not prove cause and effect, the scientists stressed.
Researchers also found an increased risk of death from all causes among top consumers of sugary drinks.
Previous studies have shown a link between added sugar and both obesity and chronic disease, but its impact on death rates has not been clear.
Lead researcher Dr Jean Welsh, from Emory University in Atlanta, US, said: “There were two parts of this question we wanted to understand. Do added sugars increase risk of death from heart disease or other causes, and, if so, is there a difference in risk between sugar-sweetened beverages and sugary foods?
“We believe this study adds strong data to what already exists highlighting the importance of minimising sugary beverages in our diet.”
The team drew on data from almost 18,000 participants in the Reasons for Geographic and Racial Differences in Stroke study, a long-running US health and lifestyle investigation.
A questionnaire was used to estimate sugary food and beverage consumption.
Sugary beverages included sodas and fruit drinks while desserts and breakfast cereals were among the sugar-sweetened foods.
Information from death records was compared with people’s sugar consumption habits while they were alive.
The findings were presented at the American Heart Association’s Epidemiology and Prevention/Lifestyle and Cardiometabolic Health Scientific Sessions meeting in New Orleans.
Consumption of sugary drinks, which have few other nutrients, results in the body being hit by a “sugar flood”, said Dr Welsh.
In contrast, sugary foods often contain other nutrients such as fats or proteins which slow down metabolism.
Dr Welsh urged doctors to start speaking with patients about sugar.
“We know that if healthcare providers don’t ask patients about lifestyle practices linked to obesity and chronic disease, patients tend to think they’re not important,” he said. “Simply asking patients about their sugary beverage consumption is valuable.”
Gavin Partington, director general of the British Soft Drinks Association, said: “Whilst we recognise health issues associated with obesity are a serious issue, it’s important to note that a study of this sort cannot prove cause and effect and does not take into account other potential lifestyle factors.
“This study conducted in America does not reflect consumption behaviour in the UK, where sugar intake from soft drinks has fallen by almost 19 per cent since 2013.
“We all have a role to play in helping to tackle obesity and we hope our actions on sugar reduction, portion size and promotion of low and no calorie products set an example for the wider food sector.”
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