Nutrition in Diabetes

Diabetes is a chronic disease that is characterized by high blood glucose (blood sugar) levels. Glucose is a common sugar found in most foods. Insulin is a hormone that plays a primary role in blood sugar control. Indeed, in healthy individuals, increased insulin levels promote the transportation of sugar into the body’s cells where it can be used for energy [1].

Type 1 diabetes develops when the body does not produce insulin, while type 2 diabetes occurs when the body cannot make or use insulin properly. Inadequate insulin levels cause sugar to remain in the blood and extremely high blood sugar levels that lead to a diabetes can cause serious health problems such as eye, nerve, kidney, and blood vessel damage, heart disease, stroke, organ failure, and poor wound healing that may result in amputations [1].

Glycemic Index

In order to help people with diabetes control their blood sugar levels, a glycemic index (GI) was established. The GI provides a score from 0 to 100 for specific foods based on the degree to which they raise blood sugar levels. Low GI foods have a score of 55 or less, medium GI foods score between 56-69, and high GI foods have a score of 70 of higher [2]. Examples of food in each category are as follows [2]:

  • Low GI foods – peanuts, steel cut rolled oats, hummus, skim milk, kidney beans, lentils, sweet potatoes, barley, brown steamed rice, carrots, and certain fruits (e.g. orange, apple).
  • Medium GI foods – grapes, bananas, raisins, couscous, corn, ice cream, and spaghetti.High GI foods – white bread, white rice, pretzels, watermelon, crackers, and beverages sweetened with sugar.

An important factor that is associated with GI is Glycemic Load, which refers to the body’s response to the amount of food that is eaten. For example, a small portion of high GI food slightly raises blood sugar, which means it has a low Glycemic Load [2]. However, the optimal way for people with diabetes to maintain healthy blood sugar levels is to eat larger portions of food with a low GI and smaller portions of food with a high GI.

Dietary Management of Blood Sugar

An increasing amount of evidence indicates that foods with a low GI and Glycemic Load have the most favorable impact of blood sugar levels [2, 3]. The sugar in low GI foods enters the bloodstream at a slower rate and this improves the body’s response to insulin. A low GI diet also helps decrease the risk of diabetic complications [4].

Role of Supplements in Diabetes Management

In addition to eating low GI foods, diabetes-specific oral nutritional supplements (ONS) have been shown to promote healthy blood sugar levels, increase body weight, and improve BMI for individuals with diabetes who were experiencing involuntary weight loss before taking the supplements [5, 6].

Similarly, diabetes-specific nutritional formulas (DSNFs) that typically contain high protein, healthy fat, fiber, carbohydrates, and amino acids, help reduce the need for insulin and decrease the incidence of infections [7, 8]. Both the short-term and long-term use of DSNFs in the form of ONS are also associated with heightened blood sugar regulation and a lower incidence of complications such as cardiovascular events [9].


  1. American Diabetes Association. Diagnosis and classification of diabetes mellitus. Diabetes Care. 2012;35 Suppl 1:S64-71.
  2. Kirpitch AR, Maryniuk MD. The 3 R’s of glycemic index: Recommendations, research, and the real world. Clinical Diabetes 201; 29(4):155-159.
  3. Opperman M, Venter C, Oosthuizen W, et al. Meta-analysis of the health effects of using the glycemic index in meal-planning. British J Nutr. 2004;92:367-381.
  4. Thomas D, Elliot EJ. Low glycaemic index, or low glycaemic load, diets for diabetes mellitus Cochrane Database of Sys Rev. 2009;1( CD006296).
  5. Mayr P, Kuhn KS, et al. A diabetes-specific oral nutritional supplement improves glycaemic control in type 2 diabetes atients. Exp Clin Endocrinol Diabetes. 2016;124(7):401-9.
  6. Magnoni D, Rouws CH, et al. Long-term use of a diabetes-specific oral nutritional supplement results in a low-postprandial glucose response in diabetes patients. Diabetes Res Clin Pract. 2008;80(1):75-82.
  7. Mesejo A, Montejo-González JC, et al. Diabetes-specific enteral nutrition formula in hyperglycemic, mechanically ventilated, critically ill patients: a prospective, open-label, blind-randomized, multicenter study. Crit Care. 2015 Nov 9;19:390.
  8. Mottalib A, Mohd-Yusof BN, et al. Impact of diabetes-specific nutritional formulas versus oatmeal on postprandial glucose, insulin, GLP-1 and postprandial lipidemia. Nutrients. 2016;8(7). pii: E443.
  9. Elia M, Ceriello A, et al. Enteral nutritional support and use of diabetes-specific formulas for patients with diabetes: a systematic review and meta-analysis. Diabetes Care. 2005;28(9):2267-79.