Those who ate the highest amount of carbohydrates that raise blood sugar, like cornflakes or white bread, developed decreased function in their blood vessels, putting them at a higher risk of heart disease.
The study is published in the June 16 issue of the Journal of the American College of Cardiology.
Another study, at the University of Alabama at Birmingham, had 16 participants lower the amount of carbs they ate each day.
After a month, those people had more stable blood sugar and reported feeling more satisfied after a meal, and the feeling lasted longer than it did for those who ate more carbs.
Researchers say because of that long-lasting feeling of fullness, cutting back on carbs may lead to less snacking during the day and fewer added pounds.