Unit I: Control of Diabetes - Four Cornerstones
The First Cornerstone of Treatment: Nutrition Therapy/Eating Patterns
Eating correctly is a vital link in proper diabetes control. While insulin provides hypoglycemic effects, what one eats is the primary source of glucose in the form of carbohydrates. Proteins and fats are also essential parts of a balanced diet. Because intake of food is usually under the willful control of the diabetic, what he/she eats can be the cause of either hypoglycemia or hyperglycemia, of control of diabetes or lack of control. Moderation and consistency are two guide-words related to what the person with diabetes eats with emphasis on moderation. "Evidence suggests that there is not an ideal percentage of calories from carbohydrate, protein, and fat for all people with diabetes" (American Diabetes Association, 2018, p. S41). The American Diabetes Association (2018) recommends referral of the patient to a registered dietitian who is well versed on medical nutrition therapy (MNT) after being diagnosed with either diabetes or pre-diabetes (p. S39). It would make sense to do this for the patient as soon as possible. It is difficult at best to conduct effective teaching in a clinic setting when time is divided among numerous important topics. Considering that what one eats/doesn't eat is usually well ingrained in the person by virtue of "personal preferences (e.g., tradition, culture, religion, health beliefs and goals, economics)," a variety of eating patterns and nutrition therapy should be considered with the individual patient to increase the likelihood of success (Evert et al., 2014, S121). Research published in 2016 concluded that “carbohydrate-counting…improve[s] glycemic control….(Bowen, Cavanaugh, Wolff, et al., 2016, p. 1368). Carbohydrate-counting (AKA carb-counting) is the antithesis of "mindless eating." Rather, it requires conscious deliberation and decision-making about what and how much will be eaten in terms of carbohydrates. More on this, below.
An important point should be made here with regard to this topic: When working with individuals who have diabetes or pre-diabetes, or have only recently been diagnosed with one or the other, try to avoid using the word "diet." Imagine, if you can, that you are the patient. Your health care provider begins to talk to you about a new diet. Does that word conjure pleasant feelings for you? That would be highly doubtful since the word diet suggests less than desirable things: "You need to eat this, not that." "You need to eat less of what you enjoy." "You can't eat ____ any longer." Avoiding the word "diet" will be difficult because it is such a common word in our vocabulary, but when working with people in whom what they eat/don't eat can make a profound impact on their health, it is important to try every way possible to keep them actively involved with a positive perspective. Make an effort to use words like "nutrition therapy" or "eating patterns" instead of diet and you may find a very different response!
The Exchange Program, Carbohydrate-Counting, the Glycemic Index, and Guidelines for Nutritional Therapy
The need for glucose must be balanced with the need to avoid excessive loads of glucose while maintaining good, all around nutrition and satiety. The American Dietetic Association (now called the Academy of Nutrition and Dietetics) in conjunction with the American Diabetes Association developed the Exchange Program for dietary management because it provides balanced nutrition and knowledgeable intake of carbohydrates, proteins, and fats. This method provides for the proper amounts and distribution of nutrients for a prescribed calorie limit, calorie and weight control, and variety. The latter quality is directly related to success with this dietary regimen.
In 1950, a joint endeavor by the American Diabetes Association, American Dietetic Association, and the U.S. Public Health Service produced a food exchange program for dietary management of diabetes. This program categorized foods into lists according to their relative amounts of carbohydrate, protein, and fat. Consequently, foods within a list could be interchanged from a nutritional perspective, but foods could not be exchanged between lists. A significant benefit afforded by this method was the great variety of food choices that was possible, while maintaining a balanced, nutritious intake of food.
Modifications were made in 1976, 1986, 1995, and again in 1998 based on the newest information related to nutrition that had come to light through research at that time. More recent revisions include notation of high fiber and high sodium foods, an increase from 2 grams of protein to 3 grams of protein for each food on the Starch List, and the addition of the following categories: Other Carbohydrate List, Combination Foods, and Free Foods.
Familiarize yourself with the lists of food types -- the foods within each list and the amount of each food. Again, please note: Exchanges occur within lists, not between them. Each food item within a list is comparable to other food items within the list in terms of carbohydrate, protein, fat, and calories. Hence, exchanges are appropriate within the list of items. (For example, one slice of bread can be exchanged for 1/2 cup of cooked cereal.) From a health perspective, it goes without saying that recommended food preparation methods include baking, broiling, and boiling, and discourage frying.
The food lists found in Appendix A were developed for this module from the original exchange program to help students learn first-hand about the exchange program of dietary management. They are not as comprehensive as the real thing, but can be used for the purposes of instruction and learning.
To gain some experience working with an exchange program format, use Appendix A to prepare a variety of meals according to the following dietary prescription for exchanges from each group identified: Remember, foods (in the serving sizes indicated) can be exchanged for one another within groups but not between groups.
As a way to really learn about this program, use the The Exchange List System for Diabetic Meal Planning for a day or two. Actually, this is an excellent way to plan healthy meals for any calorie level. It will a) increase your familiarity with the Exchange Program, and b) provide personal experience with a major life style change required for adequate control of diabetes. Or, find the program which provides the total number of calories you need in order to lose weight and provide proper nutrition at the same time. (A registered dietitian (RD) is a good resource.) In addition to the guideline that exchanges are to be made within groups, only, it is necessary for one to eat all of the food prescribed for a meal, and no more at that time. Balance is the key word. (These are two important guidelines for nutritional management in diabetes).
Carbohydrate counting is a dietary method particularly suitable to people with diabetes because the fundamental metabolic problem in diabetes relates to errors in the physiologic use of carbohydrate in food that is ingested. Counting grams of carbohydrates in foods that are to be consumed provides the opportunity to control the amount of carbohydrate that is eaten. It also allows for the accurate calculation of an insulin dose designed to manage x-number of carbohydrates at any meal.
An example can be provided by considering the following: A patient has been advised by his/her health care provider to take one unit of ultra rapid-acting insulin for every 20 grams of carbohydrate to be consumed, prior to the meal. If the individual plans to eat, for example, one cup of cereal that provides 39 grams of carbohydrate (CHO), ½ cup of skim milk (6 grams of CHO), and ½ cup of apple juice (15 grams of CHO), the total insulin dosage would be 3 units: 39 + 6 + 15 grams of CHO divided by 20 grams of CHO/unit of insulin.
Carbohydrate counting (AKA carb-counting) has been known (and used) since 1921 when diabetes was first effectively treated. It became a fundamental component of the regimen for individuals with DMT1 after the Diabetes Control and Complications Trial (DCCT) was published in 1993 (Reichard, Nilsson, & Rosenqvist, 1993). The efficacy of its use in treating persons with DMT2, in comparison to the use of an algorithm based on the weekly average of pre-meal glucose levels has being studied. Both methods were effective in reducing the subjects' A1c levels by 1.5 percentage points (Bergenstal et al., 2008, p. 1308).
In their review of the Bergenstal et al. (2008) study, two authors suggested that potential barriers to the implementation of carb-counting in DMT2 management preclude its use (Davis & Wylie-Rosett, 2008). The barriers were "the time and effort required for patients to count the carbohydrate content at each meal, patient difficulties in understanding the strategy, and the availability of dietitians or appropriately trained health care providers to teach patients" (p.1467). However, these authors also acknowledged evidence that patients in the Bergenstal et al. (2008) study who used carb-counting gained less weight than those who used the algorithm based on their average pre-meal blood glucose levels (Davis & Wylie-Rosett, 2008).
[Side note: This author could not disagree more with the above suggestion that carb-counting is too difficult to be useful. In fact, it suggests that people (patients and health care providers, alike) are generally not smart enough to grasp the concept. Once learned, it is easy to apply.]
"[C]arbohydrate counting...[has] become really important in developing an eating program for someone with diabetes . . . What is important is the total amount of carbohydrate in the diet, rather than its source" (How Sweet It Is, 1994, p. 14). Persons with diabetes are advised to work with their dietitian and health care provider to determine the ratio of the number of grams of carbohydrate they need to ingest in order to retain blood glucose levels within a normal range to the number of units of insulin they are taking. Carbohydrate counting is especially common as a part of the regimen for a diabetic using an insulin pump becuase the insulin used in a pump is fast-acting.
One need only read the nutritional labels included on the packaging of most foods, and attend carefully to the information showing the total carbohydrates in a serving (attending as carefully to the serving size included in the label), to count carbs. In addition, anyone who has learned the Exchange Program – the foods in their respective groups, and the serving sizes for each – can easily translate that one exchange of a serving in the Bread Group is equal to 15 grams of carbohydrate, and one exchange of a serving in the Fruit Group is equal to 15 grams of carbohydrate. The Milk Group has various amounts of carbohydrates, but the Meat and Fat Groups contain no carbohydrate.
Tomorrow morning, prepare a breakfast of your favorite cereal, juice, and fat-free milk, but keep the total grams of carbohydrate to 50 – no more, no less. Note that ½ cup of most juices (other than tomato juice which is considerably less) provides 15 grams of carbohydrate, and one cup of fat-free milk (or 1%, 2% or whole milk, for that matter) provides 12 grams of carbohydrate. Your challenge will be in determining how much of that cereal you love you can actually have, to make up the remaining 23 grams! Or, if you want more cereal, you might cut back on one of the other parts of your breakfast, but remember – milk and fruit are important components of balanced nutrition, and eating less than a full serving is just that: less than proper nutrition.
An overall rule is that monitoring carbohydrate intake is a key strategy in achieving glycemic control in diabetes. The Glycemic Index (GI), measures how quickly an ingested carbohydrate influences the post-meal blood glucose over a specified period of time. In this way, the GI provides an indication of the quality of a carbohydrate with reference to its effect on the blood glucose. The blood glucose increase following ingestion of high GI foods is greater than the increase following the ingestion of low GI foods. White bread is considered a gold standard in terms of the GI. It is assigned a GI value of 100, which is the highest level possible. Foods with a GI of 100 cause the fastest and most dramatic rise in blood glucose levels (Khan, 2007). Examples of high GI foods are white bread, crackers and corn flakes. Low GI foods include non-starchy vegetables, most fruits, dairy products, beans and sugars.
Making sense (and use) of the GI tends to be complicated for the following reasons:
- A food can have different GI values as a result of how ripe it is, its variety, how it is cooked and how it has been processed, and from country to country.
- The GI of a food varies significantly from person to person. For some individuals, it can even vary from day to day.
- The GI of a food eaten alone is different than when it is eaten with another food. For example, if a high GI food is eaten in combination with a low GI food, the GI response is moderate.
- Standard test portions of foods used for determining GI are not the usual portion sizes that individuals consume.
- The GI is not a reliable guide for healthy food choices. Although many healthy foods have a low GI, there are also foods of questionable nutritional value with low or moderate GI values such as soft drinks, candies, sugars and high fat foods.
At this time, research does not support the claim that eating only low GI foods causes significant weight loss or helps control appetite. For people with diabetes, monitoring total grams of carbohydrate remains the key strategy. However, some individuals with diabetes may be able to use the GI concept, along with blood glucose monitoring, to fine-tune their food choices to produce a modest improvement in post meal blood glucose levels (Franz, 2003; Raatz, et al., 2005; Skinner, 2013).
Guidelines for Nutritional Therapy
Weight loss is a key goal in the management of patients with DMT2. There are conflicting weight-loss strategies, including low-carbohydrate, low glycemic-index, low-fat vegan, conventional low-fat, and high-protein and high-monounsaturated fat eating plans. There is no evidence to suggest that one nutritional strategy is clearly the best. The most successful strategy is one that the patient can adopt and follow in the long term (Davis, Forbes, & Wylie-Rosett, 2009). For a more complete explanation of the Glycemic Index and the diabetic diet, take a look at the following: https://beyondtype1.org/glycemic-index-diet-diabetes/.
A third guideline is to eat at regular times synchronized with the action profile of the insulin or oral agent used. Except in cases where the individual takes fast-acting insulin prior to every meal, meals cannot be delayed without taking the risk of a hypoglycemic reaction. Even in the latter case, this is possible as a result of a delayed meal. Keep in mind that intermediate-acting insulins are working virtually all the time and can profoundly lower the blood sugar if a meal is delayed. If a delay is unavoidable, a snack of protein and complex carbohydrate (cheese and crackers, bread and peanut butter, for example) should be taken.
A final guideline is to boil, bake, and broil foods rather than frying them. This is a health tip for all people, diabetic or non-diabetic, but especially important for those who may be prone to high cholesterol and triglycerides.
People with diabetes should be advised/educated about the fact that diabetes confers a high risk of coronary artery disease and as such warrants limiting their intake of saturated fats and trans fatty acids -- the principal determinants of LDL (low-density lipoprotein) -- and cholesterol. In this way they may be able to reduce the already present (due to having diabetes) risk of cardiovascular disease (American Diabetes Association, 2018, p. 86-104; National Heart, Lung, and Blood Institute of the National Institutes of Health, 2002).