Consuming too many sugary sweets, desserts and drinks can triple your chances of dying from heart disease, a study has shown.
Scientists in the US found a striking association between the proportion of daily calories supplied by sugar-laden foods and heart disease death rates.
One sugar-sweetened beverage a day was enough to increase the risk of dying from cardiovascular disease (CVD) affecting the heart and arteries.
For people obtaining a quarter of their calories from added sugar, the risk tripled compared with those whose sugar contribution was less than 10%.
Sugar consumption in the top fifth of the range studied doubled the likelihood of death from heart disease.
The researchers specifically focused on added sugar in the diet - that is, sugar added in the processing or preparing of food, rather than natural sources.
Dietary guidelines from the World Health Organisation recommend that added sugar should make up less than 10% of total calorie intake.
Yet many processed foods and beverages are packed with sugar. A single can of fizzy drink, for instance, may contain 35 grams of sugar providing 140 calories.
The new study, led by Dr Quanhe Yang, from the Centres for Disease Control and Prevention in Atlanta, used US national health survey data to determine how much added sugar people were consuming.
Between 2005 and 2010, added sugar accounted for at least 10% of the calories consumed by more than 70% of the US population, the research showed.
Around a tenth of adults obtained a quarter or more of their calories from added sugar.
The data were matched against heart disease mortality over a typical period of 14.6 years, during which a total of 831 CVD deaths were recorded.
Writing in the journal JAMA Internal Medicine, the authors concluded: "Our findings indicate that most US adults consume more added sugar than is recommended for a healthy diet.
"A higher percentage of calories from added sugar is associated with significantly increased risk of CVD mortality."
Commenting on the results in the journal, Dr Laura Schmidt from the University of California at San Francisco, wrote: "We are in the midst of a paradigm shift in research on the health effects of sugar, one fuelled by extremely high rates of added sugar overconsumption in the American public.
"In sum, the study by Yang et al contributes a range of new findings to the growing body of research on sugar as an independent risk factor in chronic disease."
British expert Dr Nita Forouhi, from the Medical Research Council Epidemiology Unit at Cambridge University, called for "clear front of pack labelling of sugar content" to help consumers buying food products.
She added: "While policy makers deliberate on the pros and cons of a sugary drinks tax, there is a public health action less talked about: a health warning on soft drinks with high sugar content, recommending to limit consumption as part of a healthy diet."
Professor Naveed Satta, from the British Heart Foundation Glasgow Cardiovascular Research Centre at the University of Glasgow, said: " We have known for years about the dangers of excess saturated fat intake, an observation which led the food industry to replace unhealthy fats with presumed 'healthier' sugars in many food products.
"However, the present study, perhaps more strongly than previous ones, suggests that those whose diet is high in added sugars may also have an increased risk of heart attack. Of course, sugar per se is not harmful - we need it for the body's energy needs - but when consumed in excess it will contribute to weight gain and, in turn, may accelerate heart disease."
He added: "Helping individuals cut not only their excessive fat intake, but also refined sugar intake, could have major health benefits including lessening obesity and heart attacks. The first target, now taken up by an increasing number of countries, is to tax sugar-rich drinks."
The study showed that the average proportion of daily calories obtained from added sugar rose from 15.7% in 1988-1994 to 16.8% in 1999-2004. It decreased to 14.9% in 2005-2010.
Gavin Partington, director general of the British Soft Drinks Association, said: "Soft drinks manufacturers have led the way in reducing sugar in their products - companies with market share of around 60% are now signed up to the Responsibility Deal calorie reduction pledge.
"Furthermore, soft drinks manufacturers are committed to providing on-pack nutritional information, wider availability of smaller portion sizes and have also substantially increased their advertising and marketing expenditure on low and zero calorie drinks.
"It is important to remember that soft drinks contribute just 2% of calories to the average British diet."