Marion Franz, MS, RD, LD, CDE
People with diabetes “deserve” the right to eat healthfully along with everyone else. Yet, it often happens that the diets recommended to persons with diabetes do not promote healthy eating. To begin, what is healthy eating and what types of foods make up the right diet? And second, what types of diets do not promote healthy eating and should be avoided?
Healthy Eating Patterns
The 2010 Dietary Guidelines for Americans define a healthy eating pattern as one that emphasizes nutrition-dense foods and beverages including the following foods and food groups:
- Whole grains
- Fat-free or low-fat milk and milk products
- Lean meats and poultry
- Beans and peas
- Nuts and seeds
Research on eating patterns (similar to that recommended by the Dietary Guidelines) such as the Mediterranean and DASH patterns, has documented the health benefits of following these diets. Beyond specific foods, healthy eating is defined in general as controlling total calorie intake to achieve and sustain a healthy weight. For most people, this will mean eating fewer calories by making informed food and beverage choices along with increasing physical activity.
For good health (for people with and without diabetes,) the American Diabetes Association recommends an eating pattern that includes carbohydrates from fruits, vegetables, whole grains, legumes and low-fat milk. Individuals are also encouraged to eat foods containing fiber and whole grains, making at least half of their grains whole grains. It is the balance between the total amount of carbohydrate eaten at meals and snacks and available insulin that determines what blood glucose levels will be after eating. Therefore, monitoring carbohydrate intake, whether by carbohydrate counting, food choices or experience-based estimation, is a key strategy in achieving glycemic control rather than eliminating single food groups entirely.
Unhealthy Eating Patterns
Regarding less healthy eating patterns, both the Atkins and low-carbohydrate plans contribute to unhealthy eating practices. People who follow these diet patterns tend to eat increased amounts of saturated fat; this is a concern because research shows eating saturated fats for prolonged periods of time can lead to insulin resistance, a condition characterized by the body’s inability to respond to the insulin produced by the pancreas, resulting in uncontrolled blood sugar. When low-carb diets are compared with low-fat diets for a one-year period, studies show that while calorie intake can decrease similarly, low-fat diets provide about 30 percent of calories from fat with only 10 percent to 12 percent of calories coming from saturated fats. In contrast, low-carbohydrate diets provided 45 percent of calories from fat with 15 percent to 20 percent coming from saturated fats. Thus, low-carb diets tend promote higher intake of harmful fats in comparison with a more balanced approach. Likewise, these restrictive patterns often eliminate carbohydrate foods such as wheat or other grains which cuts out healthful grain foods that provide valuable nutrients.
Oftentimes, low-carbohydrate diets are recommended to persons with diabetes for weight loss. However, studies comparing different dietary patterns for weight loss using varying percentages of macronutrients intake (e.g., low-carb, low-fat, high-protein) conclude there is no statistical difference in the amount of weight lost (4-9 pounds total) after one year on each diet. This suggests low-carb diets are not more efficient for achieving long term weight loss over other methods. Furthermore, eight of the weight loss interventions reported no improvements in A1C, the measurement used to determine long-term blood sugar control. These findings show that a variety of eating patterns with differing macronutrient percentages are modestly effective for weight loss in persons with diabetes but generally do not improve overall health in the long-term.
Although it is clear there is not one single nutrition therapy best for persons with diabetes, the most realistic and helpful nutrition advice is to pay less attention to the scale and instead to concentrate on controlling blood sugar by eating smaller portions of healthy foods such as fruits, vegetables, grains, legumes, low-fat dairy products, lean meats and oils rich in unsaturated fats.
- Dietary Guidelines Advisory Committee (DGAC) Report on the Dietary Guidelines for Americans, 2010. Available at: http://www.cnpp.usda.gov/dgas2010-dgacreport.htm
- American Diabetes Association: Nutrition recommendations and interventions for diabetes. A position statement of the American Diabetes Association. Diabetes Care 31 (suppl 1): S61-S78, 2008
- Franz MJ. The obesity paradox and diabetes. Diabetes Spectrum. 2013, In press.
- Davis NJ, Tomuta N, Schechter C, Isasi CR, Segal-Isaacson CJ, Stein D, Zonszein JZ, Wylie-Rosett J: Comparative study of the effects of a 1-year dietary intervention of a low-carbohydrate diet versus a low-fat diet on weight and glycemic control in type 2 diabetes. Diabetes Care 32: 1147-1152, 2009
- Guldbrand H, Dizdar B, Bunjaku B, Lindström T, Bachrach-Lindström M, Fredrikson M, Fredrikson M, Östgren CJ, Nystrom FH: In type 2 diabetes, randomisation to advice to follow a low-carbohydrate diet transiently improves glycaemic control compared with advice to follow a low-fat diet producing similar weight loss. Diabetologia 55: 2118-2127, 2012
- Franz MJ, Boucher JL: Type 2 diabetes: effectiveness of weight loss interventions on metabolic outcomes. Late-breaking abstracts, American Diabetes Association Scientific Meeting, June 2013
- Larsen RN, Mann NJ, Maclean E, Shaw JE: The effect of a high-protein, low-carbohydrate diets in the treatment of type 2 diabetes: a 12 month randomized controlled trial. Diabetologia 54: 731-740, 2011
- Krebs JD, Elley CR, Parry-Strong A, Lunt H, Drury PL, Bell DA, Robinson E, Moyes SA, Mann JI: The Diabetes Excess Weight Loss (DEWL) Trial: a randomized controlled trial of high-protein versus high-carbohydrate diets over 2 years in type 2 diabetes. Diabetologia 55: 905-914, 2012
- Brehm BJ, Lattin BL, Summer SS, Boback JA, Gilchrist GM, Jandacek RJ, D’Alessio DA: One-year comparison of a high-monounsaturated fat diet with a high-carbohydrate diet in type 2 diabetes. Diabetes Care 32: 215-220, 2009