Carbohydrates And Diabetes

Carbohydrates are the most easily accessible form of energy consumed for the cells of the body to utilize. Carbohydrates include sugars, starches and fiber that is found in the vast majority of foods. Sugars and starches cause increased glucose during digestion, while fiber actually helps to remove excess glucose and fats during digestion. This is why a balanced approach to consuming carbohydrates is essential in blood glucose regulation.

Foods that are high in carbohydrates, sugar and starch, and low in dietary fiber cause the greatest spikes in blood glucose levels. They do not have to be completely removed from the diet, but they have to be consumed infrequently and with a corresponding reduction in other carbohydrates consumed during that meal. Keeping carbohydrate levels even across all meals during the day is seen as beneficial to prevent huge spikes in blood glucose levels after one or two meals a day. The more balanced the carbohydrate intake is the higher the insulin sensitivity in individuals cells will be. High spikes in blood glucose levels are linked to a decreased insulin sensitivity at all times.

Different specific foods have been linked to the increased carbohydrate consumption rates and increased rates of type 2 diabetes experienced in the United States and other developed and developing countries. In one assessment study, researchers determined the change in typical intake of dietary fat, carbohydrate, protein, fiber and corn syrup intake. Since all these foods contribute to the total energy intake, researchers broke down the dietary percentage of the individuals total energy intake as per the categories of foods. They determined that those with higher total energy from corn syrup had a higher rate of diabetes and also a lower rate of fiber intake. 1

The GI of Foods

For most individuals with diabetes, prediabetes or gestational diabetes, carbohydrate counting or using a glycemic index (GI) chart is seen as instrumental in developing a balanced diet. The GI score of a given food, which is a carbohydrate source, allows the individual to select those foods that produce a low blood glucose spike but also provide nutrients, dietary fiber and the feelings of satiation that are necessary to prevent snacking and consuming foods between meals. Generally most foods that are ranked as 55 or lower are considered to be low GI, 55 to 69 are moderate GI and high GI are 70 or above.

High GI foods tend to have very low fiber content and will digest easily and quickly in the body. High GI foods should be consumed in very limited amounts and ideally at times when the blood glucose level is natural low, such as after a fast or after times of high energy use as in moderate to intense exercise. Low GI foods tend to have high levels of both soluble and insoluble fiber, cause a decrease in the rate of glucose absorption into the blood and also provide a more gradual release of glucose into the body.

Some cultures and populations are more prone to consuming high GI diets. This would include many Asian countries where white rice forms a basis for the diet. In addition, these countries also eat high levels of vegetables and fruits and have a low intake of proteins and fats. This particularly combination may contribute to the somewhat atypical results  of low levels of obesity and diabetes often noted with the higher glycemic index food intake.

Typically in these countries, diabetes has not historically been a major health concern. Changing food intake patterns to include more processed foods in conjunction with high levels of rice and carbohydrates is seen as the largest risk factor. In a study of 64, 227 non-diabetic middle aged women it was noted that increased intake of foods with high glycemic load and glycemic index, especially rice, may be linked to a higher risk of developing type 2 diabetes. 2

Studies of using the GI with diabetic patients have shown positive results. These studies have indicated that it is not the specific GI of the individual food but rather the pattern of carbohydrate consumption and the other attributes of the food and foods consumed that is essential in short and long term blood glucose control. 3

Choosing Carbohydrates In The Diet

Eating using the GI chart is helpful, provided that diabetics stay within a specific carbohydrate amount per day. Those using insulin will need to calculate the specific carbohydrate intake per meal as well, to ensure that they give themselves the proper bolus of insulin as needed during digestion (this can be via pump or injection).

Carbohydrate information is found on the label of all foods purchased and is also available on many different websites and in diabetes information books and resources. Each person’s carbohydrate requirement will be based on activity, current weight goals and on specific types of medications that you may be taking. Charting meals in advance and watching portion control is essential in staying within your carbohydrate range per day.

In small group studies even a loose restriction of carbohydrates in those individuals with type 2 diabetes showed improvements in serum cholesterol profiles, BMI ( Body Mass Index) and HbA1c levels in the blood. 4 These individuals were provided with the information on the specifics of either the carbohydrate-reduced diet or a conventional diet but were not specifically monitored during the two years that they participated in the study. The results were obtained from an initial baseline measurement of the participants BMI, HbA1c, blood serum cholesterol and sulfonylurea measurements compared to measurements taken after two years on the specified eating program.

Looking at carbohydrates as their entire contribution to the diet, instead of as “good” or “bad” is important for diabetics. Individuals need to understand how to allow for some of the high GI carbs for special occasions while enjoying the healthy low GI carb foods regularly to maintain blood glucose levels and aid in digestion and metabolic functioning.


1 Gross, L. S., Li, L., Ford, E. S., & Liu, S. (2004). Increased consumption of refined carbohydrates and the epidemic of type 2 diabetes in the United States: an ecologic assessment. American Journal of Clinical Nutrition , 774-779.

2 Villegas, R., Lui, S., Gao, Y.-T., et al. (2007). Prospective Study of Dietary Carbohydrates, Glycemic Index, Glycemic Load, and Incidence of Type 2 Diabetes Mellitus in Middle-aged Chinese Women. Archives of Internal Medicine , 2310-2316.

3 Riccardi, G., Rivellese, A. a., & Giacco, R. (2008). Role of glycemic index and glycemic load in the healthy state, in prediabetes, and in diabetes. American Journal of Clinical Nutrition , 269S-274S.

4 Haimoto, H., Iwata, M., Wakai, K., et al. (2008). Long-term effects of a diet loosely restricting carbohydrates on HbA1c levels, BMI and tapering of sulfonylureas in type 2 diabetes: A 2-year follow-up study. Diabetes Research and Clinical Practice , 350-356.

This article was originally published July 12, 2012 and last revision and update of it was 9/10/2015.