While you need to pay attention to all three if you have diabetes, carbohydrates are the type of food that has the biggest impact on blood sugar because 90% are broken down into glucose. You can find out the carbohydrate content of packaged food by reading the food label.
"Carbohydrates include starches like bread and pasta, fruit, vegetables, legumes, milk and sugars like sucrose, honey and molasses," said Samantha Heller, RD, nutrition coordinator for the Fairfield, Conn. YMCA.
By counting carbohydrates in food, you can control the portion you have in every meal and the total you have for the day. This is a good way to get all the great nutrients in carbohydrate-laden food, while keeping blood sugar under control.
"Counting carbohydrates takes some instructions but is not difficult once you understand how many grams of carbohydrates are best for you each day," says Heller.
People who use insulin before meals often count carbohydrates so they can calculate how much insulin to take with a meal.
However, you can also count carbohydrates to make sure you don't exceed the daily amount in your meal plan, regardless of whether or not you're on diabetes medication.
"Diabetics need to be aware of how many servings of carbohydrates are in a food and where they are in their day with regard to number of servings, calories, and health choices," says Heller.
To get an sense of the carb content of your favorite foods, read How to Count Carbs in 10 Common Foods.