Dietary Goals and Exercise
Diet
The treatment goals for a diabetes diet are:
- Achieve near-normal blood glucose levels. People with type 1 diabetes must coordinate calorie intake with medication or insulin administration, exercise, and other variables to control blood glucose levels. New forms of insulin now allow more flexibility in timing meals.
- Protect the heart and aim for healthy lipid (cholesterol and triglyceride) levels and control of blood pressure.
- Achieve reasonable weight. A reasonable weight is usually defined as a weight that is achievable and sustainable, rather than one that is culturally defined as desirable or ideal. Children, pregnant women, and people recovering from illness should be sure to maintain adequate calories for health.
- Manage or prevent complications of diabetes. People with diabetes, whether type 1 or 2, are at risk for a number of medical complications, including heart and kidney disease. Dietary requirements for diabetes must take these disorders into consideration.
- Promote overall health.
Overall Guidelines. There is no such thing as a single diabetes diet. Patients should meet with a professional dietitian to plan an individualized diet within the general guidelines that takes into consideration their own health needs.
Healthy eating habits along with good control of blood glucose are the basic goals, and several good dietary methods are available to meet them. General dietary guidelines for diabetes recommend:
- Carbohydrates should provide 45 - 65% of total daily calories. The type and amount of carbohydrate are both important. Best choices are vegetables, fruits, beans, and whole grains. These foods are also high in fiber. Patients with diabetes should monitor their carbohydrate intake either through carbohydrate counting or meal planning exchange lists.
- Fats should provide 25 - 35% of daily calories. Monounsaturated (olive, peanut, and canola oils; avocados; nuts) and omega-3 polyunsaturated (fish, flaxseed oil, and walnuts) fats are the best types. Limit saturated fat (red meat, butter) to less than 7% of daily calories. Choose nonfat or low-fat dairy instead of whole milk products. Limit trans-fats (hydrogenated fat found in snack foods, fried foods, commercially baked goods) to less than 1% of total calories.
- Protein should provide 12 - 20% of daily calories, although this may vary depending on a patient’s individual health requirements. Patients with kidney disease should limit protein intake to less than 10% of calories. Fish, soy, and poultry are better protein choices than red meat.
[For more information, see In-Depth Report #42: Diabetes diet.]
Weight Management
Being overweight is the number one risk factor for type 2 diabetes. Even modest weight loss can help prevent type 2 diabetes from developing. It can also help control or even stop progression of type 2 diabetes in people with the condition and reduce risk factors for heart disease. Patients should lose weight if their body mass index (BMI) is 25 - 29 (overweight) or higher (obese).
The American Diabetes Association recommends that patients aim for a small but consistent weight loss of ½ - 1 pound per week. Most patients should follow a diet that supplies at least 1,000 - 1,200 kcal/day for women and 1,200 - 1,600 kcal/day for men.
Unfortunately, not only is weight loss difficult to sustain, but many of the oral medications used in type 2 diabetes cause weight gain as a side effect. For obese patients who cannot control weight using dietary measures alone, weight-loss drugs, such as orlistat (Xenical) or sibutramine (Meridia), may be helpful. Orlistat may have specific benefits for people with diabetes. It may not only help achieve weight but also improve glucose, cholesterol, and lipid levels. In 2007, the FDA approved a non-prescription form of orlistat (alli). [For more information, see In-Depth Report #53: Obesity.]
Exercise
Sedentary habits, especially watching TV, are associated with significantly higher risks for obesity and type 2 diabetes. Regular exercise, even of moderate intensity (such as brisk walking), improves insulin sensitivity and may play a significant role in preventing type 2 diabetes -- regardless of weight loss. An important study reported a 58% lower risk for type 2 diabetes in adults who performed moderate exercise for as little as 2.5 hours a week.
Aerobic Exercise. Aerobic exercise has significant and particular benefits for people with diabetes. Regular aerobic exercise, even of moderate intensity, improves insulin sensitivity. People with diabetes are at particular risk for heart disease, so the heart-protective effects of aerobic exercise are especially important. Moderate exercise protects the heart in people with type 2 diabetes, even if they have no risk factors for heart disease other than diabetes itself.
For improving glycemic control, the American Diabetes Association recommends at least 150 minutes per week of moderate-intensity physical activity (50 - 70% of maximum heart rate) or at least 90 minutes per week of vigorous aerobic exercise (more than 70% of maximum heart rate). Exercise at least 3 days a week, and do not go more than 2 consecutive days without physical activity.
Strength Training. Strength training, which increases muscle and reduces fat, is also helpful for people with diabetes who are able to do this type of exercise. The American Diabetes Association recommends performing resistance exercise three times a week. Build up to three sets of 8 - 10 repetitions using weight that you cannot lift more than 8 - 10 times without developing fatigue. Be sure that your strength training targets all of the major muscle groups.
Exercise Precautions. The following are precautions for all people with diabetes, both type 1 and type 2:
- Because people with diabetes are at higher than average risk for heart disease, they should always check with their doctors before undertaking vigorous exercise. For fastest results, frequent high-intensity (not high-impact) exercises are best for people who are cleared by their doctors. For people who have been sedentary or have other medical problems, lower-intensity exercises are recommended.
- Strenuous strength training or high-impact exercise is not recommended for people with uncontrolled diabetes. Such exercises can strain weakened blood vessels in the eyes of patients with retinopathy. High-impact exercise may also injure blood vessels in the feet.
Patients who are taking medications that lower blood glucose, particularly insulin, should take special precautions before embarking on a workout program:
- Monitor glucose levels before, during, and after workouts (glucose levels swing dramatically during exercise).
- Avoid exercise if glucose levels are above 300 mg/dL or under 100 mg/dL.
- Inject insulin in sites away from the muscles used during exercise; this can help avoid hypoglycemia.
- Drink plenty of fluids before and during exercise; avoid alcohol, which increases the risk of hypoglycemia.
- Insulin-dependent athletes may need to decrease insulin doses or take in more carbohydrates prior to exercise, but may need to take an extra dose of insulin after exercise (stress hormones released during exercise may increase blood glucose levels).
- Wear good, protective footwear to help avoid injuries and wounds to the feet.
- Some blood pressure drugs can interfere with exercise capacity. Patients who use blood pressure medication should talk to their doctors about how to balance medications and exercise. Patients with high blood pressure should also aim to breathe as normally as possible during exercise. Holding the breath can increase blood pressure.
[For more information, see In-Depth Report #29: Exercise.]
Improving Sleep
Some research suggests that not getting enough sleep may impair insulin use and increase the risk for obesity. More research is needed, but it is always wise to improve sleep habits.
