I often get this question from diabetics that come into my office. This is usually combined with another question “How many carbohydrates should I have?”. Unfortunately there is not one definite answer. Everyone is different in how they process carbohydrates and you will have to do some investigating first to find what works best for you.
There are three macronutrients: protein, carbohydrates, and fat. Of these three nutrients, carbohydrates affect blood sugar in diabetics the most. Some type 2 diabetics are sensitive to specific types of carbohydrates such as rice or corn and then others can’t tolerate large amounts of carbohydrate containing foods in general.
The quality of carbohydrates matters as well. Carbohydrates come in three main forms: starch, fiber, and sugar. Starch includes enriched grains (where the outer layers of the grain have been removed) and starchy vegetables such as peas, corn, beans, and potatoes. Fiber is the indigestible carbohydrate commonly found in whole grains, nuts, legumes, fresh fruits and vegetables. Sugar comes in two forms: natural and added. Natural sugars are found in milk and fruit while added sugars include table sugar, syrups, and many other forms which have been added to foods often in large quantities. When choosing foods containing carbohydrates, the best options are those with a high amount of fiber. As you increase you fiber intake, it’s also important to increase your water intake to help prevent constipation. However, that doesn’t mean you have to avoid starches and sugar, but rather limit them.
A good place to start when trying to determine how many carbohydrates you should have in the day is to record your food intake (include grams from carbohydrates and portion sizes) along with your blood sugars on paper. Take a look at how your blood sugars compared to your carbohydrate intake per meal. Are your blood sugars high after eating a specific meal? See if you can decrease your carb intake or maybe you are sensitive to a specific carbohydrate food. You may also benefit from recording any additional activities that could affect your blood sugar such as stress, illnesses, and exercise. By recording your intake and blood sugars together, you will be able to see trends which can provide a clue as to what needs to be changed in your diet.
But this still begs the question of how many grams of carbohydrates you need per day. After you have totaled up your grams of carbohydrate intake for the day, multiply that number by 4 (there are 4 calories per gram of carbohydrate) and then divide by the number of calories you consumed that day. A good first goal is to consume approximately 40-45% of carbohydrates from calories. For example, if you need 2000 calories to maintain your weight, that would be 200g – 225g per day. These grams should be spread out as evenly as possible over 3 meals and allowing 15-30 grams for snacks as needed. However, some people may need to go lower but you won’t know this until you have recorded your intake above with your blood sugars and noticed this trend. If you see that your blood sugars are not within an appropriate range and are not sure what needs to be done, take your results to a healthcare provider such as a doctor, registered dietitian, and/or certified diabetes educator who can help you make the changes needed to get you to your goals.