They said people who ate more added sugar were more likely to have higher risk factors for heart disease, such as higher triglycerides and lower levels of protective high-density lipoprotein or HDL cholesterol.
"Just like eating a high-fat diet can increase your levels of triglycerides and high cholesterol, eating sugar can also affect those same lipids," Dr. Miriam Vos of Emory School of Medicine, who worked on the study published in the Journal of the American Medical Association, said in a statement.
The study adds to mounting pressure on U.S. food companies to make their foods healthier as newly passed U.S. health reform legislation shifts the nation's focus on ways to prevent, rather than simply treat disease.
A report by the influential Institute of Medicine released on Tuesday recommended that the U.S. Food and Drug Administration start to regulate sodium intake in foods.
And several states, including New York and California, have weighed a tax on sweetened soft drinks to defray the cost of treating obesity-related diseases.
The addition of sweeteners to prepared foods and beverages in recent decades has sharply increased Americans' daily intake of sugar and overall calories, according to Vos and colleagues.
But no major studies have looked at the impact of too much sugar on levels of fat in the blood.
The researchers asked 6,000 adults what they ate and then grouped them by sugar intake and cholesterol levels.
On average, nearly 16 percent of people's daily calories came from added sugar.
The highest-consuming group ate an average of 46 teaspoons of added sugar per day, while the lowest-consuming group ate an average of only about 3 teaspoons daily.
"It would be important for long-term health for people to start looking at how much added sugar they're getting and finding ways to reduce that," Vos said in a statement.
Too much sugar not only contributes to obesity, but also is a key culprit in diabetes, high blood pressure, heart disease and stroke, according to the American Heart Association.
The association warned last August that Americans need to cut back dramatically on sugar consumption, recommending that women eat no more than 100 calories per day of added processed sugar a day, or six teaspoons (25 grams), while men should keep it to just 150 calories of added processed sugar per said or nine teaspoons (37.5 grams).
Kelly Brownell of Yale University told Reuters last month a penny-per-ounce (penny-per-28 grams) tax on soft drinks could cut the consumption of sugar-sweetened drinks by the average American from 50 gallons (189 liters) annually to 38.5 gallons (146 liters).
He expects such a tax could also cut healthcare costs by about $50 billion over 10 years and raise $150 billion in revenue over the same period.
The American Beverage Association says sugar-sweetened drinks do not pose any particular health risk, and are not a unique risk factor for obesity or heart disease