The study, of 61 adults on insulin pump therapy, found that those who learned to count carbs had a small reduction in weight and waist size after six months.
They also reported gains in quality of life and - at least for those who consistently counted their carbs with each meal - an improvement in blood sugar levels.
The findings, published online by the journal Diabetes Care and scheduled to appear in the April print issue, do not prove that carb counting is the answer for people with type 1 diabetes.
But it is widely recommended that people on insulin try to estimate the carbohydrate content of their meals to help calculate their insulin doses, said Dr. Sanjeev Mehta, of the Joslin Diabetes Center and Harvard Medical School in Boston.
Carbohydrate counting is one way to do that, noted Mehta, who was not involved in the study.
Other ways include paying close attention to portion size, using diabetes "exchange lists" and choosing foods based on "glycemic index" -- a measure of how far and how fast a given foods sends up blood sugar.