Patient information: Lifestyle modifications in type 2 diabetes
David K McCulloch, MD
UpToDate performs a continuous review of over 375 journals and other resources. Updates are added as important new information is published. The literature review for version 15.3 is current through August 2007; this topic was last changed on April 28, 2006. The next version of UpToDate (16.1) will be released in March 2008.
INTRODUCTION — Diabetes mellitus is a chronic condition, but people with diabetes can lead a full life while keeping their diabetes under control. Lifestyle modifications (changes in day-to-day habits) are an essential component of any diabetes management plan.
Lifestyle modifications can be a very effective way to keep diabetes in control. Improved blood glucose control can slow the progression of long-term complications. Multiple small changes can lead to improvements in diabetes control, including a decreased need for medication.
Diabetes requires a lifelong management plan, and persons with diabetes have a central role in this plan. Lifestyle modifications are an opportunity for diabetics to take charge of their health. Therefore, it is important to learn as much as possible about diabetes and to take an active role in making decisions about health care and treatment.
DIETARY CHANGES — Healthcare providers may recommend specific dietary changes for people with diabetes, depending upon the patient's therapy goals. Dietary changes can help with weight loss, improve blood glucose control, and lower blood cholesterol levels and blood pressure.
Calories — Lifestyle changes that promote weight loss are the primary lifestyle treatment for people with type 2 diabetes who are overweight. Improving caloric balance (eating fewer calories than are used by the body) should be consider the primary goal of lifestyle modification.
Weight loss can improve blood glucose control by decreasing insulin resistance and partially restoring the normal insulin-producing function of the pancreas. Weight loss can also lower blood pressure; high blood pressure and obesity are both risk factors in the development of cardiovascular disease. Weight gain can be a problem in patients who take insulin stimulators (like sulfonylureas, or meglitinides), thiazolidinediones (like pioglitazone and rosiglitazone) or who take insulin.
A sensible and sustainable diet, which may include reducing the number of calories eaten each day, allows for gradual weight loss over time. A healthcare provider or nutritionist can discuss an ideal weight goal with help to plan a safe and effective overall weight-loss program. While reducing calories and increasing activity are beneficial to anyone who is overweight, a focus on carbohydrate counting may also be useful for patient using insulin stimulators (like sulfonylureas and meglitinides) and insulin.
Carbohydrate counting — It is possible to adjust an insulin dose based upon the amount of carbohydrates eaten. The number of carbohydrates can be determined using nutrition labels or carbohydrate calculators (show figure 1). The dose of insulin needed based on carbohydrates eaten varies from one patient to another, and can be determined with the help of a healthcare provider
(table 1)
Carbohydrate counting: getting started Step 1: Know the goalEating about the same amount of carbohydrate at meals and snacks each day will help to keep blood glucose levels from getting too high or too low.Focus on keeping the amount of carbohydrate intake moderate to keep your blood glucose levels from going too high. Remember, it is not healthy to cut out all carbohydrate foods; the body, especially your brain, needs some every day.Step 2: Monitoring intake and blood glucoseKeeping a daily food and blood glucose record will help inform what affects blood glucose levels.Measuring or weighing foods are helpful in the beginning to learn what common food portions look like.Step 3: Methods of counting carbohydrateTo count carbohydrates, there are two methods. Patients may also blend the two methods.Read food labels: Look at the grams of total carbohydrate on the label. Remember, the nutrition information on food labels is for the standard serving size. If the portion is larger or smaller, it is necessary to adjust the carbohydrate information. Use the exchange system: Estimation of carbohydrate content can be broken down into food groups that are standardized for carbohydrate content according to particular portions. For example, one serving from the Bread/Starch, Fruit, or Milk group each contains between 12 and 15 grams of carbohydrate. Vegetables contribute little carbohydrate and are not counted.
Post-meal blood glucose management — Blood glucose levels can rise sharply after meals. Increasing the amount of soluble fiber in the meal may slow and/or lessen this rise, and may decrease the dose of insulin needed. Soluble fiber is found in fruits, vegetables, and beans. A high-fiber diet can also lower levels of low-density lipoprotein (LDL) cholesterol (sometimes called "bad" cholesterol).
Eating foods with a low glycemic index is another approach for controlling post-meal blood glucose levels. A diet of low-glycemic index foods may also decrease LDL cholesterol levels. The glycemic index of some foods is shown in the Table (show table 2).
Glycemic index of foodsFoodGlycemic indexBaked russet potato135
Cornflakes119
White bread100
Whole meal bread99
Brown rice96
Raisins93
White rice83
Banana (raw)79
All-Bran73
Sweet potato70Spaghetti (white)66
Spaghetti (whole wheat)61
Baked beans (tinned) 60
Ice cream, yogurt, whole milk, apple (raw) 49-53
Red lentils43
Soya beans (tinned)20
Increasing the dose or changing the timing of very rapid or rapid-acting insulin before meals can help control post-meal glucose levels. Very rapid-acting insulin (lispro [Humalog®], aspart [Novolog®], or glulisine [Apidra®]) should be given within 15 minutes of eating, while rapid acting insulin (Regular or R) should be given 30 to 60 minutes before a meal (show table 3).Other approaches that can help to reduce the rise in blood glucose levels after meals include the use of alpha-glucosidase inhibitors (like acarbose or miglitol) which can be taken as a pill with the first bite of a meal. These drugs slow down the rate at which starch is broken down into glucose and so delay the absorption of glucose into the blood after a meal. These drugs are effective in some people although they can cause flatulence and diarrhea as a side effect.
Two new injectable therapies (pramlintide [Symlin®], and exenatide [Byetta®]) can also decrease the rise in blood glucose after a meal. They can also increase satiety and decrease hunger which can lead to weight loss in some patients. However, both of these drugs can cause significant nausea in some patients. In addition, patients who are taking insulin will need to reduce their insulin dose if pramlintide or exenatide are added.
Dietary guidelines — The ratio of carbohydrates, protein, and fat is important to long-term health. Current recommendations are as follows:
- Carbohydrates: 45 to 65 percent of total calories
- Protein: 5 to 20 percent
- Fat: 25 to 30 percent (mostly monounsaturated or polyunsaturated, not saturated fat)
A low carbohydrate diet has shown favorable results in short-term studies for persons trying to improve blood glucose control, cholesterol, and lose weight. Persons with type 2 diabetes may consider a low carbohydrate diet, but should work with their healthcare provider to individualize a plan.
A moderate-salt or low-salt diet is often recommended; a low-salt diet is especially useful for lowering high blood pressure.
Timing of food intake — Consistent timing of food intake is not necessary for all people with diabetes. However, people using intensive insulin treatment may find it easier to control their blood sugar levels when they eat approximately the same amount of carbohydrates at the same time each day.
Establishing healthy dietary habits — To get started with healthy eating habits, a patient may be asked to keep a food diary, discuss current eating patterns, attend a dietary class for people with diabetes, or meet with a dietitian. Eating habits should be changed slowly, making it easier to adopt new habits.
ALCOHOL USE — The recommendations for alcohol use in persons who are diabetic are similar to those for non-diabetics. On a daily basis, no more than two alcoholic beverages for men or one alcoholic beverage for women are recommended. One alcoholic beverage is defined as 12 ounces of beer, 5 ounces of wine, or 1.5 ounces of spirits (all of which contain 15 grams of alcohol).
Alcohol can cause either low or high blood glucose, depending upon the amount of alcohol consumed, if food was eaten at the same time, and the history of prior alcohol use or abuse. Persons with diabetes who choose to drink alcohol should drink moderately.
A moderate intake of alcohol may lower blood pressure and decrease the risk of coronary artery disease and stroke. However, excessive use of alcohol can increase the risk of neurologic and liver disease and high blood pressure.
QUITTING SMOKING — Over 25 percent of people newly diagnosed with diabetes are smokers. Quitting smoking is one of the most important things a patient can do to improve their health.
Smokers with diabetes have an increased risk of the following:
- Death, especially from heart attacks and strokes
- High "bad" cholesterol levels
- Worsened blood glucose controlled, compared to non-smokers
- Neurologic complications from diabetes
- Kidney disease leading to dialysis
- Foot ulcer and amputation of toes, feet or legs caused by peripheral vascular disease
EXERCISE — Exercise is beneficial for all individuals, with or without diabetes. Even persons with longstanding diabetes or diabetic complications can benefit from exercise.
For diabetics, exercise promotes cardiovascular fitness and weight loss, lowers high blood pressure, improves lipid profiles, improves blood glucose control in some cases, and leads to an overall sense of well-being. It may even help prevent type 2 diabetes in some people.
General exercise precautions — It is important to balance enthusiasm and common sense when beginning an exercise program. These precautions encourage patients to stay safe and ensure that exercise is productive.
- Wear well-fitting, protective footwear (See "Patient information: Foot care in diabetes").
- Drink adequate liquids before, during, and after exercise to prevent dehydration, which can upset blood glucose levels.
- Measure blood glucose before, during, and after exercise to determine their body's typical response to exercise. If the pre-exercise blood glucose reading is 250 mg/dL or higher, exercise should be postponed until the level is under control.
- Consider a decrease in insulin dose by about 30 percent during exercise.
- Choose an insulin injection site away from exercising muscles (for example, avoid the legs if running)
- Keeping rapidly absorbed carbohydrates on hand (glucose tablets, hard candies, or juice).
- Eat a snack 15 to 30 minutes before exercise, and again every 30 minutes during exercise.
- Eat a source of slowly absorbed carbohydrates (dried fruit, fruit jerky, granola bars, or trail mix) immediately after exercise. This will counter a post-exercise drop in blood glucose levels.
Type of exercise — Gentle aerobic exercises, which increase the heart rate for a sustained period of time, are often the best choice for diabetics. Examples of aerobic exercise include walking, cycling, swimming, or rowing. Diabetics with well-controlled blood glucose levels and no complications can usually participate in most any type of exercise.
Choose exercise that is enjoyable and can be performed comfortably, making it easier to stay motivated and stick with a program over time. People who are accustomed to a sedentary lifestyle may find it particularly challenging to start and continue with an exercise program. Talk with a healthcare provider about any barriers that stand in the way of exercise; he or she may be able to suggest solutions.
People with diabetic eye complications (proliferative retinopathy) may be advised to avoid high-impact activities and strenuous weight-lifting, which can increase blood pressure and cause bleeding in the eye. People with neurologic complications (peripheral neuropathy) are usually advised to avoid traumatic weight-bearing exercises such as running, which can lead to foot ulcers and stress fractures although this depends on the severity of the nerve damage.
Intensity — Exercise does not have to be intense to be beneficial. Persons who want to increase the intensity of exercise should do so gradually, and should stop if he or she experience worrisome symptoms, such as chest discomfort or nausea.
Duration — A reasonable exercise session consists of 10 minutes of stretching and warm-up, followed by 20 minutes of gentle aerobic exercise. Eventually, you may wish to exercise for more than 30 minutes at a time. You should increase the duration of exercise gradually.
Timing — People who take insulin should try to exercise at the same time of the day. This practice can help to maintain predictable blood glucose levels.
Frequency — Most of the benefits of exercise for people with diabetes require a regular, long-term exercise program. Patients should commit to exercising 30 minutes a day most days of the week.
MEDICATIONS AND BLOOD GLUCOSE MONITORING — The day-to-day management of blood glucose levels can be complicated. Management may require a schedule of oral medications and/or insulin, frequent blood glucose monitoring, and carefully planned meals and snacks.
However, successful management of diabetes does not have to take the enjoyment out of life. It can be difficult to establish a routine that incorporates all aspects of diabetes care, though many people find that the routine becomes second nature once established. Written schedules may help patients to remember the details of a routine until they are committed to memory. It is also important to carefully manage situations that can complicate blood glucose control, such as sick days and vacations.
People with diabetes may need to take several medications throughout the day. Medications to lower high blood pressure, lower cholesterol levels, and low-dose aspirin may be used to manage and prevent complications. Each prescription should be taken exactly as directed on a daily basis. If the medication schedule is complex, a pill organizer or written outline may be helpful in remembering to take specific medications at specific times.
ROUTINE MEDICAL CARE — Making lifestyle changes is an excellent step towards diabetes management. However, routine medical care is important for people with diabetes; this may include frequent medical appointments and screening tests. Your healthcare team will periodically reevaluate the diabetes management plan, and can work to detect health problems that do not cause symptoms in the early stages.
Finally, it is important to listen to your body and seek care if questions or problems arise. This may require calling and seeing a clinician between scheduled appointments. Even persons who have had diabetes for many years have difficulty some times, and clinicians are skilled in helping to solve problems.
<A class=boldfont name=21>WHERE TO GET MORE INFORMATION — Your healthcare provider is the best source of information for questions and concerns related to your medical problem. Because no two patients are exactly alike and recommendations can vary from one person to another, it is important to seek guidance from a provider who is familiar with your individual situation.
This discussion will be updated as needed every four months on our web site (www.patients.uptodate.com). Additional topics as well as selected discussions written for healthcare professionals are also available for those who would like more detailed information. Some of the most pertinent include:
A number of web sites have information about medical problems and treatments, although it can be difficult to know which sites are reputable. Information provided by the National Institutes of Health, national medical societies and some other well-established organizations are often reliable sources of information, although the frequency with which they are updated is variable.
- National Library of Medicine
- National Institue of Diabetes and Digestive and Kidney Diseases
- American Diabetes Association (ADA)
(www.diabetes.org)
- The Hormone Foundation
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