Diet is one of the major factors influencing management of diabetes. It has the biggest impact on patients’ glucose (blood sugar). In addition, a healthy weight can prevent or dramatically reduce the odds of developing prediabetes, type 2 diabetes, gestational diabetes and double diabetes. It can also minimize complications in those who already have diabetes.

People often think of diet as a temporary tactic to lose weight. Instead it should be viewed as a lifetime strategy of eating the right kinds and amounts of food at the right times to help feel good and prevent health problems.

Diet planning is a cornerstone of diabetes management. In some cases, changes to diet – along with regular exercise and other lifestyle modifications (e.g., quitting smoking, limiting alcohol) – can be enough to keep diabetes symptoms under control. In other cases, diet may be part of an overall treatment plan that also includes drug therapy with insulin or antidiabetic agents.

Patients with diabetes are generally advised to eat around the same time each day, eat meals that are nutritionally balanced and strive for weight management. Excess weight contributes to insulin resistance not just in people with type 2 diabetes but also in those with type 1 diabetes and other forms of diabetes.

A good diet is well-balanced with foods that provide a variety of nutrients, including vitamins and minerals. Foods that can be part of a sound diet include:

• Vegetables and legumes
• Whole grains
• Fruits
• Nuts and seeds
• Low-fat dairy products
• Fish, poultry and lean meats

In general, people should consume between 1,200 and 2,400 calories a day, depending on their size, gender and energy requirements. In addition, at least eight glasses of water or other nonalcoholic and unsweetened liquids are recommended. Carbohydrates, proteins and fats are the three main categories of nutrients that provide energy to the body. The American Diabetes Association (ADA) recommends that meals contain the following breakdown of nutrients (although recommendations vary slightly for those with high levels of LDL cholesterol):

Carbohydrates are the body’s main source of energy and provide the greatest influence on a person’s glucose levels. A large serving of carbohydrates in a single sitting, particularly low-fiber, high-sugar foods, is likely to boost glucose levels. For this reason, it is important to include not only carbohydrates but also protein and fats within a meal.

In addition, people with diabetes need to keep close track of the grams of carbohydrates they consume. This will allow patients to adjust insulin levels to best meet the rise in blood glucose brought on by carbohydrate consumption. Patients can track carbohydrate intake through either carbohydrate counting or diabetic food exchange lists.

The ADA’s latest dietary guidelines, issued in 2006, emphasize fiber-rich complex carbohydrates. Its recommendations for people with diabetes include eating nonfried fish at least twice a week, restricting intake of cholesterol to less than 200 milligrams a day and restricting trans fats.

The timing of meals can be almost as important as the content. Diabetic patients are often advised to eat several small meals throughout the day rather than two or three large ones. Patients may be advised to snack before, during or after physical activity because of the interaction between exercise and blood sugar. Some patients are advised to eat in the evening to prevent nocturnal hypoglycemia and the Somogyi effect (rebound hyperglycemia in the morning).

The potential role of diet as a risk factor for diabetes is controversial. Some research has suggested that excessive consumption of sugar can contribute to the development of type 2 diabetes, but organizations such as the ADA state that eating sugar does not cause diabetes. Some research has indicated that consumption of cow’s milk at a young age may be a risk factor for type 1 diabetes, but other scientists have not found any such connection.

Patients should meet with their physician and a registered dietitian for nutrition counseling. No single meal plan is right for everybody, and the most effective plans are those that are tailored most closely to a patient’s needs and dietary preferences. Factors that may be taken into consideration when planning meals include:

• Glucose levels
• Blood pressure
• Weight goals
• Lifestyle and food preferences
• Amount of exercise
• Other health factors (such as unhealthy levels of cholesterol)

Patients should look for dietitians registered with the Commission on Dietetic Registration of the American Dietetic Association. Registered dietitians must complete 75 hours of continuing education every five years.

Some dietitians specialize in the nutritional management of diabetes and become certified diabetes educators (CDEs), a designation granted by the National Certification Board of Diabetes Educators. They can help patients craft a meal plan that will help patients keep body weight and glucose at optimal levels.