Expired activity
Please go to the PowerPak homepage and select a course.

Module 6. Healthy Eating With Diabetes

Nutrition is one of the most controversial health topics, with opinions about what constitutes a healthy diet ranging from one extreme (e.g., low carbohydrate) to the other (e.g., low fat). Diet is a major consideration for those managing diabetes and, while carbohydrates have garnered the most interest related to glycemic control, other dietary components are likely equally important.

Given the controversies related to nutrition, even some of the most reputable organizations, such as the American Diabetes Association (ADA), have chosen to refrain from giving specific dietary guidelines to people with diabetes, stating in their Standards of Care that, “there is not a one-size-fits-all eating pattern for individuals with diabetes.”1 The ADA further states that studies examining the ideal amount of carbohydrate intake for people with diabetes are inconclusive. However, they do acknowledge that “monitoring carbohydrate intake and considering the available insulin” can improve postprandial control. The United States Department of Agriculture (USDA) MyPlate guide to eating is the most current food guide pyramid (i.e., accessible at ChooseMyPlate.gov). MyPlate provides nutritional guidance to the American population as a whole; but, it is not necessarily the key to eating as a means to control blood glucose levels in people with diabetes or pre-diabetes. MyPlate recommends that half of an individual’s daily plate of food consist of fruits and vegetables. While such dietary intake will likely increase the intake of nutrients and phytochemicals,2 produce varies widely in its nutritional content and, therefore, in its glycemic impact on people with diabetes.3

Many people with type 2 diabetes mellitus (T2DM) are counseled to lose weight to help manage or potentially reverse diabetes or pre-diabetes. Weight loss may be a useful goal for people with T2DM who are overweight, but it may have to exceed 5% in order to impact blood glucose control.4 Sustaining a weight loss of as little as 5% to 7% of body weight can lead to a decrease in insulin resistance and improvement in blood glucose control and, therefore, allows for a reduction in the amount of medication taken.5 Along the same lines, even preventing excessive weight gain in those with type 1 diabetes mellitus (T1DM) can help keep insulin action high and insulin needs lower by preventing or reducing insulin resistance.6 While the nutrition focus in this module is on the benefits of balancing carbohydrates, fats, and protein in the diet to control blood glucose levels, improvements in body weight will likely also result from a healthier diet and other lifestyle improvements.

What Constitutes a Healthy Diet for People With Diabetes?

Carbohydrates, fats, and proteins are the dietary macronutrients that provide energy for activity and routine body functioning, although each of these nutrients has a different primary role. Protein helps to build muscle and other bodily structures, while fat is important as a source of stored energy and contributes to the health of the brain, nerves, hair, skin, and nails. Carbohydrate is a major fuel source for the body, especially during physical activity, and is the primary supplier of energy for the brain, nerves, and muscles.

The quality of dietary fats and carbohydrates consumed is more crucial than is the quantity of these macronutrients. Diets rich in whole grains, fruits, vegetables, legumes, and nuts; moderate in alcohol consumption; and lower in refined grains, red or processed meats, and sugar-sweetened beverages have been shown to reduce the risk of diabetes and improve glycemic control and blood lipids in patients with diabetes.7 A recent systematic review concluded that there is currently insufficient evidence to suggest that any particular diet is superior for treating overweight and obese patients with T2DM; although the Mediterranean, vegan, and low-glycemic index diets appear to be promising.8 When overall diet quality is emphasized, several dietary patterns, such as Mediterranean, low-glycemic index, moderately low carbohydrate intake, and vegetarian diets, can be tailored to personal and cultural food preferences and appropriate calorie needs for weight control and diabetes prevention and management.9-11

Regardless of a patient’s overall dietary pattern, it helps to check blood glucose levels before and after meals to learn how foods affect each individual, particularly for those ingesting a lot of carbohydrates (e.g., such as potatoes, bread, rice, and pasta). People should focus on keeping portion sizes reasonable and appropriate for a specific height and target BMI (i.e., if weight loss is a goal) and manage blood glucose levels by providing a good balance of carbohydrates, fats, and protein. Everyone, including all people with diabetes, will benefit from an appropriate balance of these 3 macronutrients.

Sidebar: Does Your Plate Look Like This?

The Joslin Diabetes Center in Boston, world-renowned for its management and treatment of diabetes, suggests that daily food intake for people with diabetes should resemble the plate in Figure 1 more than the USDA MyPlate guidelines, which recommend that half of the plate be comprised of fruits and vegetables. How close to the Joslin plate is your eating plan?

Figure 1. Joslin Diabetes Center: Plate
Figure 1. Joslin Diabetes Center: Plate

  • Is your plate covered with fruits and vegetables that vary in color: dark green, orange, yellow, and red?
  • Has the fat been trimmed from your meat and the skin removed?
  • Did you choose leaner cuts of meat, poultry, or fish?
  • Did you choose whole-grain pastas or breads? Brown rice or potato with skin?
  • How much fat was used in cooking or added to your plate?
  • Did you boil, steam, grill, or bake instead of frying your foods?
Adapted from Joslin Diabetes Center education materials. Copyright © 2012 by Joslin Diabetes Center (www.joslin.org). All rights reserved.

Carbohydrate Intake

Carbohydrates have the greatest impact on the amount of glucose in the blood because they are converted to glucose relatively quickly. Many people with diabetes try to avoid or limit their intake of carbohydrates as a way to maintain healthy blood glucose levels, but the human body requires the fiber found in plant foods. Carbohydrates are also the body’s first choice for fuel during many physical activities; so, not having enough in the diet may limit a person’s ability to exercise optimally.

Many people with diabetes count the grams of carbohydrates in foods to help them control their blood glucose levels, and others choose carbohydrates based on their glycemic index (i.e., how rapidly the food item raises blood glucose levels).12 The exact amount of carbohydrates a person with diabetes should ingest varies based on physical activity levels, medications used, and overall insulin action. Starches and sugars ideally should be limited, but not fiber and non-starchy vegetables, such as salad greens, peppers, tomatoes, green beans, carrots, cauliflower, and onions.

Fiber Intake: Fiber includes all indigestible polysaccharides (i.e., a type of complex carbohydrate), including the natural ones in foods and others that are extracted or isolated from foods or made synthetically (e.g., Metamucil fiber supplement).13 Soluble fiber, which is found in oatmeal, legumes, seeds, fruits (e.g., apples, bananas, citrus fruits), and vegetables, dissolves in water, is partially metabolized in the large intestine by health-promoting bacteria, and helps lower blood cholesterol. Oats in particular may have a strong anti-inflammatory effect by increasing these healthful bacteria in the intestinal tract.14 An insoluble form of fiber is found in carrots, celery, and the skins of corn kernels; fruit peels, cores, and seeds; brown rice; and whole grains. Acting as roughage, most fiber passes through the human digestive system without being fully digested and ensures regular bowel movements. Since it resists acids and digestive enzymes in the stomach, fiber cannot be fully digested and does not add calories to the diet.

In addition to those previously mentioned, dietary fiber has many other health and metabolic benefits.13 For instance, a high-fiber diet may help reduce the chances of developing heart disease, diabetes, obesity, strokes, colorectal and other types of cancer, diverticulosis, and hemorrhoids.13 Fiber adds bulk and aids in portion control because it generally slows down the rate at which food empties from the stomach, makes people feel full longer, and prevents excessive eating and weight gain. From a diabetes and a personal health standpoint, dietary fiber may reduce blood glucose and cholesterol, all while slowing the digestion of carbohydrates to glucose, thereby keeping blood glucose levels more stable.

Current research is focusing on the role of the gut microbiome—the bacteria that reside in the intestinal tract—on human health and disease. The human body hosts 100 trillion, mostly benign bacteria, which help digest food, program the immune system, prevent infection, and even influence mood and behavior. The bacteria living on and in us make up an ecosystem that likely plays a role in many conditions that genes and environmental factors alone fail to explain, including obesity, autism, depression, asthma, irritable bowel syndrome, and even cancer.15

In fact, it is very possible that the type of bacteria people have in their gut has a huge impact on whether they gain weight or stay slim, get diabetes or avoid it, and develop other chronic diseases or stay healthier.16 Although this research is ongoing, it is clear is that fiber enhances the gut’s abundance of the good bacteria that reduce inflammation. For no other reason, patients with diabetes (and other metabolic health conditions) should eat as much fiber as possible to keep their health-promoting gut bacteria thriving and abundant.

Sidebar: Eat More Dietary Fiber

The low-carbohydrate craze has resulted in many products with added fiber (including pasta and tortilla shells); but, in general, the more refined a product is, the less fiber it has. To find out the fiber content of any food, either read its nutrition label (if it comes in a box or package) or look up information online (https://fnic.nal.usda.gov/food-composition/macronutrients/fiber). A reasonable fiber goal is a minimum of 12.5 grams per 1000 calories daily.


A good target is at least 20 to 35 grams of dietary fiber per day. Fiber is found only in plant-based foods, such as oats, oat bran, ground flaxseed, beans, fruits, wheat bran, apple peels, and most vegetables. Instead of trying to eat a certain amount, it may be easier to simply eat more nutritious types of plants, fruits, and vegetables, in addition to whole grains, legumes, nuts, and seeds.

Fat Intake

Diabetes can result in unhealthy changes in blood fats. In addition, elevated levels of triglycerides, which can result from eating highly refined carbohydrates and less healthy types of cholesterol, plays a major role in stimulating the inflammatory process leading to the development of cardiovascular disease common to people with diabetes.17 Not every type of fat is bad, although the proposed health benefits attributed to various types of fats are still being hotly debated in the nutrition world. But, it has been proven that a high intake of certain types of fat, as well as the intake of refined carbohydrates, can contribute to the development of insulin resistance and negative changes in blood fats.18

Eat Fewer Trans Fats and Processed Fats: Trans fats are created by manufacturers when they hydrogenate or partially hydrogenate liquid oils to alter their texture. Consumption of trans fats found in hydrogenated oils contributes to insulin resistance and makes it harder to control blood glucose and cholesterol levels. Found most abundantly in processed foods, crackers, cookies, and baked goods, trans fats may be disguised as monoglycerides and diglycerides, stearate, palmitate, lard, vegetable shortening, and hydrogenated or partially hydrogenated oils. The minimal amount of trans fats found in natural sources (e.g., cheese), however, are not considered as unhealthy as the manufactured trans fats.19

Highly processed meats (e.g., bacon, sausage, and lunch meats) are also likely bad for health because of the preservatives added. For example, eating even one fast food meal high in both manufactured trans fats and highly processed fats can interrupt the normal flow of blood through arteries and veins for hours afterward and make the body’s response to insulin sluggish as well. Conversely, eating a high-fat breakfast that contains mostly a good fat, such as olive oil, allows blood glucose and insulin levels to stay lower.20 A high intake of highly processed meat has been associated with a higher risk of T2DM.21,22

Interesterified fat is another type of manufactured fat that is currently being added to processed foods in place of trans fats; but, because it is a newer product, it does not have to be reported or listed on food labels. Studies show that this new type of altered fat may not be heart-healthy and may be as detrimental to the human cardiovascular system as trans fats.23,24

Eat More Omega fats and Healthy Plant Fats: The following 2 dietary polyunsaturated fats are essential to good health: omega-3 and omega-6 fats. Both are important to include in a healthy diet, particularly for people with diabetes whose nutrition is even more important to preserve their long-term health.

Omega-3 fats are abundant in dark green, leafy vegetables (e.g., dark-colored lettuce, spinach, kale, turnip greens), canola oil, flaxseed oil, soy, some nuts (e.g., walnuts), fish, and fish oils.

Only fish and fish oils contain larger amounts of the 2 omega-3 fats called docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) that are critical for brain and nerve function, cardiovascular health, and more. Plant foods contain mainly the essential omega-3 fat called alpha-linolenic acid (ALA), which may be converted, by the body, into DHA and EPA if intake is low.

Omega-6 fats are abundant in the corn, sunflower, peanut, and soy oils used to make food products, such as margarine, salad dressing, and cooking oils, and they may actually help lower inflammation.25 A high vegetable fat intake may decrease type 2 diabetes risk for women.26

Diets high in certain types of fat, such as the plant-based fats found naturally in avocados, may actually improve insulin action. Even tropical oils that are saturated and minimally processed are considered healthier options (e.g., coconut). Unnaturally low-fat diets can cause the liver to produce more bad cholesterol, especially if people replace fat with refined carbohydrates.18

It is best to reduce or avoid the intake of unhealthy fats by eating more foods in their natural state, foods that have not been processed, such as high-fiber vegetables, legumes, and fish. Blood cholesterol levels are more likely to decrease with a diet moderate in fat (i.e., 30% of daily calories) that does not include the low-fat versions of snack foods, which are comprised of sugars and more refined carbohydrates added to improve taste and consistency.18

Healthiness of Fat in Red Meat, Dairy, Eggs, and Nuts

The topic of red meat being a health concern has been accepted since the 1960s. Studies have shown that the likely culprit in red meat is carnitine, and gut microbes that break down this compound into harmful byproducts such as TAMO that has been associated with atherosclerosis risk.21 The old adage remains true for now, the less red meat in your diet, the better. Do not despair though, many healthier choices are available, including fish, nuts, legumes, fruits, and vegetables. As a method of reducing calorie intake, it is safe to suggest or recommend consumption of the low-calorie or low-fat versions of dairy products, such as cheese and milk.27 Also, diets rich in the monounsaturated fats found in olive oil, canola oil, and nuts and seeds are heart healthy and do not necessarily promote weight gain. Actually, if someone is following a weight loss diet and eats a handful of almonds or other nuts daily, he or she is likely to lose more weight than eating the same number of calories without the nuts.28

Blood cholesterol levels should decrease as people eliminate trans fats and other processed fats from their diets. Everyone must have a certain amount of cholesterol, which is a waxy, fat-like substance important in cell and hormone composition; the liver will excrete cholesterol as needed. Cholesterol is found in all animal products, including meat, poultry, dairy, eggs, and all types of fish, but not in plants. More recent studies indicate that the cholesterol found in eggs may not be as detrimental as once thought; the cholesterol in egg yolks has not been proven to raise blood cholesterol levels or increase the risk for cardiovascular disease.50

Protein Intake

Protein has a minimal and immediate effect on blood glucose levels and it aids in the sensation of fullness. In fact, low-protein meal plans are associated with increased hunger; therefore, eating more lean protein along with healthy fats may reduce appetite and help people achieve and maintain a lower calorie intake. Adequate intake of protein also helps to maintain lean body mass, so it is beneficial for those who lose weight on a diet or gain more muscle mass from exercising, and eating enough protein is important for aging well.

Most foods with a significant amount of protein have a lower glycemic effect because protein is metabolized more slowly than carbohydrates, usually within 3 to 4 hours. In patients with T2DM, an increase in protein intake does not increase plasma glucose; but it will increase the insulin response and leads to lower A1C levels.29 In fact, consuming as much as 30% to 40% of calories as protein, with a lower intake of carbohydrates and fats, may assist with diabetes control, weight loss, and weight maintenance. However, a high intake of protein from processed meats actually increases diabetes risk.22 Advise patients to choose high-quality sources of protein, such as lean meats and poultry, soy products, legumes, and fish. Moreover, a diet rich in soy protein appears to have a lasting beneficial effect for people with T2DM because it lowers fasting blood glucose levels, blood fats, C-reactive protein (an indicator of inflammation), and markers of kidney disease.

In the past, protein intake has been blamed for declines in kidney function and frequently restricted in the diets of people with diabetes for that reason. However, the relationship between protein intake as grams per kilogram of body weight and albumin excretion rate is very weak, except for patients with hypertension and, particularly, for those with uncontrolled diabetes. Currently, a protein intake of 0.8 to 1 g/kg should be recommended only for patients with diabetes and chronic kidney disease, whereas all others with diabetes do not need to reduce protein intake to less than 1 g/kg of body weight.29

Carbohydrate Counting Versus Calorie Counting

Estimating how much insulin is needed to cover meals and snacks is frequently difficult. Many people with diabetes have been taught to count carbohydrates; so, they try to estimate the actual amount of carbohydrates, in grams, ingested and give themselves specific doses of mealtime insulin based on an insulin-to-carbohydrate ratio that works for them. Although carbohydrate counting has been shown to improve glycemic control, it is far from an exact science30 and a nearly impossible task for individuals with below average health literacy or numeracy skills.1 When weight loss occurs as the successful outcome of a Mediterranean, vegan, or low-glycemic index diet, greater improvements in A1C levels can be seen as compared with more standard dietary patterns followed by adults with T2DM who are overweight.8

More recently, it has been recognized that estimating protein intake for individuals with T1DM is also important for controlling spikes in blood glucose after meals—rather than only estimating and accounting for carbohydrate intake—because some of the protein is converted into glucose (albeit more slowly than carbohydrates).31 Protein takes 3 to 4 hours to be fully metabolized and some can be converted into blood glucose when digested; therefore, a higher protein intake can contribute to higher blood glucose levels later on, mostly for people who have to inject or pump appropriate amounts of insulin and are using rapid-acting insulin analogues.

To complicate matters, eating a meal with more fat in it has also been shown to increase insulin needs for those with T1DM, even when the carbohydrate content is held constant, suggesting that alternative insulin dosing algorithms are needed for higher-fat meals.32 Fat may slow down, slightly, the absorption of carbohydrates in the meal, but it does not change the overall blood glucose peak.33 Vegan meals have been suggested as a healthy alternative for people with T2DM, but their higher carbohydrate content may result in greater postprandial increases in blood glucose compared with meat-based dietary patterns.3

Thus, all calories can potentially raise blood glucose at some point, not just those coming from carbohydrates.34,35 This critical point was aptly made in a recent review of all studies done to date, which reported that high-fat and high-protein meals both require more total insulin than a meal with less fat or protein and an identical carbohydrate content.36 If a person with diabetes is unable to release enough insulin to cover blood glucose increases arising from the consumption of all types of macronutrients, he or she will need to take exogenous doses of insulin to compensate.

Importance of Glycemic Index, Glycemic Load, and Food Insulin Index

Glycemic Index (GI)

How rapidly a carbohydrate is digested affects insulin responses and the ability to control blood glucose, as reflected by its glycemic index (GI). The more rapidly a food is broken down, the faster the carbohydrate is turned into blood glucose. To deal with the influx of glucose coming from high-GI carbohydrates, the pancreas must release a large amount of insulin; those with diabetes or prediabetes may not be able to cover glucose spikes with enough insulin.12

The latest GI database is accessible through www.glycemicindex.com. GI values are usually scaled from 0 to 100, with glucose having a GI of 100. High-GI foods have a GI value of 70 or higher, including almost everything with highly refined flour or added sugars like most breakfast cereals, pretzels, sugary candy, crackers, and bread. White potatoes may be natural, but they have a high GI.

Other carbohydrates cause less of a spike in blood glucose levels and are generally easier for the body to handle in moderate amounts. Sweet potatoes, rice (white or brown), oatmeal, and white sugar have GI values in the range of 56 to 69, which gives them a medium GI. Most whole fruits, fructose (fruit sugar), dairy products, legumes (beans), and pasta (white or whole wheat) fall into the low-GI category (55 and lower).

The GI of a particular food can differ from one person to the next and it can also be affected by the type and amount of carbohydrate, fat, and protein a food contains; the amount of fiber and the nature of any starches in it; its preparation (raw or cooked); its ripeness; and its acidity. For instance, thick linguine has a lower GI value than thin spaghetti. Overcooking, in general, raises the GI value of foods, so al dente pasta is better. Highly acidic foods like vinegar can lower the GI value of other foods consumed with it. Cold storage increases the resistant starch content (i.e., carbohydrates that are hard to digest) by more than one-third and the acid in lemon juice, lime juice, or vinegar will slow gastric emptying.

An excessive intake of high-GI carbohydrate foods can increase insulin resistance, even for people without diabetes.37 The standard GI values of foods have been established using the values from individuals without diabetes. This accounts for the variability and, so, their effect may be further exaggerated if someone releases less insulin or has impaired insulin action; therefore, GI values may underestimate rather than overestimate the glycemic spikes caused by most carbohydrate-rich foods in people with diabetes.

Lowering the glycemic effect of meals is beneficial. For adults who are overweight, insulin resistance can be decreased with a diet consisting of low-GI, whole-grain foods, instead of a diet consisting of more refined sugars. People with T2DM who follow a low-GI diet (i.e., less than 40) improve their blood glucose control, enhance insulin action, lower bad blood fats, and lose weight.38,39 Such positive results support the GI as an appropriate guide to eating more nutritious foods whether an individual has diabetes, pre-diabetes, or insulin resistance, or if someone just wants to stay healthy.12

Factor in Glycemic Load (GL)

When it comes to carbohydrates, portion size does matter. Glycemic load (GL) is a measure of both GI value and total carbohydrate intake in a typical serving. A GL of 20 or more is high, 11 to 19 is medium, and 10 or less is low. Foods that have a low GL almost always have a lower GI value; the following is one exception to this rule: watermelon has a high GI value (72), but the carbohydrate content per serving of this fruit is minimal, making its glycemic load (4) low. However, a serving of watermelon is a little more than a cup. Popcorn also has a higher GI value (72), but it takes a lot to equal a 50 gram serving with a GL of just 8.

GL is a very important consideration for those with diabetes.40 A high-GI/GL diet will most likely worsen insulin resistance and overtax the body’s ability to supply insulin. People should limit their intake of foods with both a medium- or high-GI value and a high GL. Any carbohydrate-heavy meal with a high GL will require more insulin, but if the GI value is not also high—as is generally the case with high-fiber foods—blood glucose will stay lower. Legumes, which are rich in protein and fiber, contain carbohydrates with a lower GI. A low-GL, high-fiber diet also raises circulating levels of adiponectin, an anti-inflammatory hormone released by fat cells that can increase insulin action and improve blood glucose control. A low GI/GL diet plan results in weight loss as well.39

Sidebar: Use GI and GL to Lower Blood Glucose

  • Choose slowly absorbed carbohydrates, not necessarily just a smaller amount of total carbohydrates
  • Use GI to identify the best carbohydrate choices, choosing foods with a lower GI
  • Limit portion size when eating carbohydrate-rich foods like rice, pasta, beans, or noodles to limit the overall GL

Food Insulin Index (FII): An Alternative to GI and GL

One issue with the use of GI to manage blood glucose levels is that the GI does not consider concurrent insulin responses. Some of the same researchers who developed the GI have since attempted to systematically rate insulin responses to common foods, instead of simply postprandial glucose spikes, the result being the food insulin index (FII), an alternate measurement that can be used in place of counting GI or carbohydrates.41 The results of the initial FII study done on healthy adults without diabetes reported that the relative insulin demand evoked by mixed meals is best predicted by a physiologic index based on actual insulin responses to isoenergetic portions of single foods. They also found that when consuming mixed meals with the same calorie content, but with varying macronutrient content, carbohydrate counting was of limited value in predicting insulin needs.

The FII is effective for people with diabetes. By way of example, in a recent study involving adults with T1DM, compared with carbohydrate counting, use of the FII algorithm substantially decreased glucose incremental area under the curve over 3 hours (i.e., measured with continuous glucose monitoring) and peak glucose excursion, and improved by 30% the percentage of time glucose levels were in a normal range (i.e., defined as 72 to 180 mg/dL, or 4 to 10 mM).42 It also works well for adults with T2DM, who had less postprandial hyperinsulinemia after eating a low-FII meal, thereby potentially improving insulin resistance and beta-cell function.43

Use of Sugar, Sugar Alcohols, and Other Sugar Substitutes

Foods that are higher in fiber are also, on the whole, lower in added sugars, fat, and calories. White sugar has only a medium-GI value and a low GL, but the health impact of eating a lot of white sugar and other refined carbohydrates is not trivial, particularly given their lack of essential nutrients and high calorie content. While it is not necessary to give up refined sugars completely, limiting their intake will help with glycemic control and cholesterol levels as well.

One of the easiest ways to start lowering the sugar content of a person’s diet and improving its glycemic effect is to reduce or eliminate the intake of all regular soft drinks, fruit juice drinks, and sugar-sweetened iced tea or lemonade. Substitute sugary drinks with water, diet soft drinks (especially the non-caffeinated, non-cola varieties), or other artificially sweetened beverages, such as Crystal Light.

As for fructose, there is nothing inherently evil about this simple sugar naturally found in fruit, despite research that has suggested that high-fructose corn syrup in beverages leads to a fatty liver. More likely, it is an excess intake of calories that leads to such health issues, not fructose.44

Some products are touted as sugar free because they contain sugar alcohols, which are reduced-calorie sweeteners (i.e., usually about half the number of calories as sugar). Blood glucose responses to different sugar alcohols (e.g., sorbitol, xylitol, and lactitol) may vary; but, in general, they will have less of an impact on blood glucose levels than other carbohydrates because these types of sugars are not fully metabolized into calories. Although helpful for reducing calories and blood glucose, sugar alcohols are not completely calorie free and may cause a laxative effect in some people.

Finally, using sugar substitutes or other low-calorie sweeteners may help people reduce their calorie intake. They also reduce the intake of high-GI carbohydrates when used in place of sugar to sweeten coffee, tea, cereal, or fruit by adding sweetness without calories. Approved sugar substitutes include saccharin, aspartame, acesulfame potassium, sucralose, neotame, tagatose, and stevia, to name a few. All are considered safe to use and are recommended for people with diabetes by the American Diabetes Association. Sucralose (Splenda) is one of the most popular ones and has largely replaced aspartame (NutraSweet) in many products, but some people are sensitive to it and experience negative reactions like headaches or stomach upset. Newest to the market is Stevia, a sweetener and sugar substitute extracted from the leaves of the plant species Stevia rebaudiana found in South America. It is 200 times sweeter than sugar, but contains no calories and is a more natural product alternative.

Coffee and Caffeine

Caffeine has no calories and it stimulates metabolism; so, it presents the following questions: Can people with diabetes have regular coffee with breakfast? Can people with diabetes drink diet colas, iced tea, and other caffeinated drinks? According to the latest research, caffeine can make the body more insulin resistant, rather than improving the chance of avoiding diabetes by drinking coffee, as earlier studies had claimed.45,46 In lean people, obese people, and people T2DM equally, caffeine ingestion in the amount equivalent to 2 to 3 8-ounce cups of coffee a day (i.e., 5 mg per kg of body weight) reduces insulin action by about one-third and the caffeine-induced decrement is still present after as many as 3 months of moderate aerobic exercise (which usually increases insulin action).47

The effects of coffee drinking have been studied in people controlling T2DM with diet, exercise, and oral medications only. Participants wearing a glucose monitor continuously for 72 hours revealed that 2 cups of coffee daily increased blood glucose levels by 8%.48 Caffeine intake also exaggerated the rise in their blood glucose after meals as follows: by 9% after breakfast, 15% after lunch, and 26% after dinner. People with T2DM who had caffeine before doing an oral glucose tolerance test were also more insulin resistant.49

Interpreting Food Labels and Determining Portion Sizes

Food Labels

Serving Size is always at the top of the nutrition facts label. The nutrition information provided is for the serving size that is stated on the label. Remember that the serving size on the label may not be the same as the portions that people usually eat. To determine the grams of carbohydrate, other macronutrients, or calories in a given product, be sure to check the serving size because the official serving sizes can be quite small as compared with how much people usually consume at one seating.

For the control of blood glucose, people should focus on the grams of total carbohydrate rather than the grams of sugar listed in the indented list that follows. Sugars and fiber are counted as part of the grams of total carbohydrate. If a food contains fiber, however, people should subtract the fiber grams from the total carbohydrate for a more accurate estimate of the carbohydrate content of a food because fiber is not digested—particularly if each serving contains 3 or more grams of fiber. If a food contains sugar alcohols, subtract one half of the grams of sugar alcohols listed on the label from the total carbohydrate content as they are not fully metabolized. Added Sugars, as a subcategory of Sugars has finally been added to food labels to make it easier for consumers to understand that there may be a health difference between something like the sugars naturally occurring in fruit (fructose) and the white sugars added to beverages and processed foods.

Manufacturers must list ingredients in the order of descending weight. In many products, refined sugar would be listed first; or it may be disguised as 4 or 5 different sweeteners that appear lower on the list. Look for sugar equivalents, such as sucrose, dextrose, high-fructose corn syrup, corn syrup, glucose, fructose, maltose, levulose, honey, brown sugar, and molasses, in the ingredient list. They are all now included as part of the Added Sugars and Total Carbs.

Portion Control

Although it may not be accurate to designate any foodstuff as completely bad for health, some foods should be eaten in small quantities only. It is important to remember, however, that many people experience something referred to as portion distortion and become confused about what an appropriate portion size may be for a person of a specific weight and height. People tend to interpret the size of their meal, regardless of how big or small it is, to be an appropriate portion. By definition, a serving size is not the amount a person puts on his or her plate; rather, it is a specific amount of food, defined as cups, ounces, or pieces, whereas a portion is the amount of food that a person chooses to eat, which can be more or less than a serving. Standardized serving sizes are required to be listed on all food labels, but even these are currently being revised by the USDA.

Sidebar: Portion Versus Serving Sizes

  • Many people think the portion in front of them is the appropriate portion size to eat, regardless of how big or small it actually is
  • A serving size is a determined amount on a food label and may or may not be the correct portion size
  • What is an appropriate portion size varies from person to person

Most people do not conceptualize portions very well; nor do they have a good sense of their hunger or satiety. For instance, researchers gave participants a lunch of macaroni and cheese every day and each day they were unknowingly served larger and larger portions of macaroni and cheese, leading them to eat more each day without realizing it. In another study, participants who ate from secretly refilling bowls were estimated to have eaten 73% more soup than controls; but, these participants reported feeling no more satisfied than those who ate less soup and fewer calories.

Conclusions

There is a lot of controversy regarding what constitutes a healthy diet, especially for those with diabetes. However, a balanced intake of carbohydrates, fats, and proteins; a severe reduction in the consumption of processed foods, refined sugars, and carbohydrates; combined with an increase in the amount of fiber consumed daily will likely improve glycemic control and the overall health of all individuals with or without diabetes. Counting carbohydrates may not be as useful as controlling overall calorie intake and choosing foods that require less insulin (as determined with the food insulin index), although use of the GI and GL can be improve outcomes. Sugar substitutes are safe for people with diabetes and can help reduce both glucose spikes and calorie intake. It is also important to recognize an appropriate serving of food and realize that a perceived portion may not necessarily be the same as an appropriate serving. Overall, it is possible for people with diabetes to improve their overall glycemic control and health with appropriate changes to their diet.

Counseling Tips for Pharmacists
Category Counseling Tips
General Diabetes Education
  • There is insufficient evidence to suggest that any particular diet is superior for treating overweight and obese patients with type 2 diabetes; but the Mediterranean, vegan, and low-glycemic index diets show promise.9
  • Diets rich in whole grains, fruits, vegetables, legumes, and nuts; moderate in alcohol consumption; and lower in refined grains, red or processed meats, and sugar-sweetened beverages have been shown to reduce the risk of diabetes and improve glycemic control and blood lipids in patients with diabetes.7
  • Carbohydrates have the greatest impact on the amount of glucose in the blood because they are converted to glucose relatively quickly.8
  • Carbohydrates are also the body's first choice for fuel during many physical activities; so, not having enough in the diet may limit a person's ability to exercise optimally.6
  • People with diabetes should eat as much fiber as possible to keep their health-promoting gut bacteria thriving and abundant.13
  • Eat Fewer Trans Fats and Processed Fats: Trans fats are created by manufacturers when they hydrogenate or partially hydrogenate liquid oils to alter their texture.
  • Eat More Omega fats and Healthy Plant Fats: Omega-3 fats can be found in dark green, leafy vegetables, canola oil, flaxseed oil, soy, some nuts, fish, and fish oils. Omega-6 fats are abundant in the corn, sunflower, peanut, and soy oils used to make food products, such as margarine, salad dressing, and cooking oils.
  • Protein has a minimal and immediate effect on blood glucose levels and it aids in the sensation of fullness.29
  • All calories can potentially raise blood glucose at some point, not just those coming from carbohydrates.
  • One of the easiest ways to start lowering the sugar content of a person's diet and improving its glycemic effect is to reduce or eliminate the intake of all regular soft drinks, fruit juice drinks, and sugar-sweetened iced tea or lemonade.

Update 9/2016

In May of this year the FDA made regulatory changes to food labeling that will help consumers better understand the content of their food choices. The new Nutrition Facts label will include a new design to make it easier to understand calories and serving size. Historically, it has been difficult for consumers to understand the concept of what actually constitutes one serving. This will be highlighted on the new labeling. A percentage daily value of added sugars will also be included in the new labeling, as well as the type of fat contained in a product, not just calories from fat. The new labeling must be on all affected food products by July, 2018.

Changes to the Nutrition Facts Label
http://www.fda.gov/Food/GuidanceRegulation/GuidanceDocumentsRegulatoryInformation/LabelingNutrition/ucm385663.htm. Accessed May 18, 2016

REFERENCES

  1. American Diabetes Association. 3. Foundations of care and comprehensive medical evaluation. Diabetes Care. 2016;39(suppl 1):S23-S35.
  2. Slavin JL, Lloyd B. Health benefits of fruits and vegetables. Advances in nutrition. Bethesda, Md. 2012;3:506-516.
  3. Belinova L, Kahleova H, Malinska H, et al. Differential acute postprandial effects of processed meat and isocaloric vegan meals on the gastrointestinal hormone response in subjects suffering from type 2 diabetes and healthy controls: a randomized crossover study. PLoS One. 2014;9:e107561.
  4. Franz MJ, Boucher JL, Rutten-Ramos S, VanWormer JJ. Lifestyle weight-loss intervention outcomes in overweight and obese adults with type 2 diabetes: a systematic review and meta-analysis of randomized clinical trials. J Acad Nutr Diet. 2015;115:1447-1463.
  5. Mitri J, Hamdy O. Diabetes medications and body weight. Expert Opin Drug Saf. 2009;8:573-584.
  6. Brazeau AS, Leroux C, Mircescu H, Rabasa-Lhoret R. Physical activity level and body composition among adults with type 1 diabetes. Diabet Med. 2012;29:e402-408. doi:10.1111/j.1464-5491.2012.03757.x.
  7. Ley SH, Hamdy O, Mohan V, Hu FB. Prevention and management of type 2 diabetes: dietary components and nutritional strategies. Lancet. 2014;383:1999-2007.
  8. Emadian A, Andrews RC, England CY, et al. The effect of macronutrients on glycaemic control: a systematic review of dietary randomised controlled trials in overweight and obese adults with type 2 diabetes in which there was no difference in weight loss between treatment groups. Br J Nutr. 2015;114:1656-1666.
  9. Turner-McGrievy GM, Barnard ND, Cohen J, et al. Changes in nutrient intake and dietary quality among participants with type 2 diabetes following a low-fat vegan diet or a conventional diabetes diet for 22 weeks. J Am Diet Assoc. 2008;108:1636-1645.
  10. Evert AB, Boucher JL, Cypress M, et al. Nutrition therapy recommendations for the management of adults with diabetes. Diabetes Care. 2014;37(suppl 1):S120-S143.
  11. Carter P, Achana F, Troughton J, et al. A Mediterranean diet improves HbA1c but not fasting blood glucose compared to alternative dietary strategies: a network meta-analysis. J Hum Nutr Diet. 2014;27:280-297.
  12. Brand-Miller J, McMillan-Price J, Steinbeck K, Caterson I. Dietary glycemic index: health implications. J Am Coll Nutr. 2009;28(suppl):446s-449s.
  13. Otles S, Ozgoz S. Health effects of dietary fiber. Acta Sci Pol Technol Aliment. 2014;13:191-202.
  14. Rose DJ. Impact of whole grains on the gut microbiota: the next frontier for oats? Br J Nutr. 2014;112(suppl 2):S44-S49.
  15. West CE, Renz H, Jenmalm MC, et al. The gut microbiota and inflammatory noncommunicable diseases: associations and potentials for gut microbiota therapies. J Allergy Clin Immunol. 2015;135:3-13; quiz 14.
  16. Blaut M. Gut microbiota and energy balance: role in obesity. Proc Nutr Soc. 2015;74:227-234.
  17. Woodman RJ, Chew GT, Watts GF. Mechanisms, significance and treatment of vascular dysfunction in type 2 diabetes mellitus: focus on lipid-regulating therapy. Drugs. 2005;65:31-74.
  18. Siri-Tarino PW, Sun Q, Hu FB, Krauss RM. Saturated fat, carbohydrate, and cardiovascular disease. Am J Clin Nutr. 2010;91:502-509.
  19. Gayet-Boyer C, Tenenhaus-Aziza F, Prunet C, et al. Is there a linear relationship between the dose of ruminant trans-fatty acids and cardiovascular risk markers in healthy subjects: results from a systematic review and meta-regression of randomised clinical trials. Br J Nutr. 2014;112:1914-1922.
  20. Kay CD, Kris-Etherton PM, West SG. Effects of antioxidant-rich foods on vascular reactivity: review of the clinical evidence. Curr Atheroscler Rep. 2006;8:510-522.
  21. Micha R, Michas G, Lajous M, Mozaffarian D. Processing of meats and cardiovascular risk: time to focus on preservatives. BMC Med. 2013;11:136.
  22. Ericson U, Sonestedt E, Gullberg B, et al. High intakes of protein and processed meat associate with increased incidence of type 2 diabetes. Br J Nutr. 2013;109:1143-1153.
  23. Hayes KC, Pronczuk A. Replacing trans fat: the argument for palm oil with a cautionary note on interesterification. J Am Coll Nutr. 2010;29(suppl 3):253s-284s.
  24. Sundram K, Karupaiah T, Hayes KC. Stearic acid-rich interesterified fat and trans-rich fat raise the LDL/HDL ratio and plasma glucose relative to palm olein in humans. Nutr Metab. 2007;4:3.
  25. Bjermo H, Iggman D, Kullberg J, et al. Effects of n-6 PUFAs compared with SFAs on liver fat, lipoproteins, and inflammation in abdominal obesity: a randomized controlled trial. Am J Clin Nutr. 2012;95:1003-1012.
  26. Alhazmi A, Stojanovski E, McEvoy M, Garg ML. Macronutrient intakes and development of type 2 diabetes: a systematic review and meta-analysis of cohort studies. J Am Coll Nutr. 2012;31:243-258.
  27. Benatar JR, Sidhu K, Stewart RA. Effects of high and low fat dairy food on cardio-metabolic risk factors: a meta-analysis of randomized studies. PLoS One. 2013;8:e76480.
  28. Sabate J. Nut consumption and body weight. Am J Clin Nutr. 2003;78(suppl 3):647s-650s.
  29. Hamdy O, Horton ES. Protein content in diabetes nutrition plan. Curr Diab Rep. 2011;11:111-119.
  30. Brazeau AS, Mircescu H, Desjardins K, et al. Carbohydrate counting accuracy and blood glucose variability in adults with type 1 diabetes. Diabetes Res Clin Pract. 2013;99:19-23.
  31. Bell KJ, Gray R, Munns D, et al. Estimating insulin demand for protein-containing foods using the food insulin index. Eur J Clin Nutr. 2014;68:1055-1059.
  32. Wolpert HA, Atakov-Castillo A, Smith SA, Steil GM. Dietary fat acutely increases glucose concentrations and insulin requirements in patients with type 1 diabetes: implications for carbohydrate-based bolus dose calculation and intensive diabetes management. Diabetes Care. 2013;36:810-816.
  33. Wolever TM, Mullan YM. Sugars and fat have different effects on postprandial glucose responses in normal and type 1 diabetic subjects. Nutr Metab Cardiovasc Dis. 2011;21:719-725. doi: 10.1016/j.numecd.2010.12.005. Epub 1 Feb 16.
  34. Bao J, Atkinson F, Petocz P, et al. Prediction of postprandial glycemia and insulinemia in lean, young, healthy adults: glycemic load compared with carbohydrate content alone. Am J Clin Nutr. 2011;93:984-996.
  35. Peters AL, Davidson MB. Protein and fat effects on glucose responses and insulin requirements in subjects with insulin-dependent diabetes mellitus. Am J Clin Nutr. 1993;58:555-560.
  36. Bell KJ, Smart CE, Steil GM, et al. Impact of fat, protein, and glycemic index on postprandial glucose control in type 1 diabetes: implications for intensive diabetes management in the continuous glucose monitoring era. Diabetes Care. 2015;38:1008-1015.
  37. Brand-Miller J, Buyken AE. The glycemic index issue. Curr Opin Lipidol. 2012;23:62-67.
  38. Stephenson EJ, Smiles W, Hawley JA. The relationship between exercise, nutrition and type 2 diabetes. Med Sport Sci. 2014;60:1-10.
  39. Turner-McGrievy GM, Jenkins DJ, Barnard ND, et al. Decreases in dietary glycemic index are related to weight loss among individuals following therapeutic diets for type 2 diabetes. J Nutr. 2011;141:1469-1474.
  40. Brand-Miller JC. Postprandial glycemia, glycemic index, and the prevention of type 2 diabetes. Am J Clin Nutr. 2004;80:243-244.
  41. Bao J, de Jong V, Atkinson F, et al. Food insulin index: physiologic basis for predicting insulin demand evoked by composite meals. Am J Clin Nutr. 2009;90:986-992.
  42. Bao J, Gilbertson HR, Gray R, et al. Improving the estimation of mealtime insulin dose in adults with type 1 diabetes: the Normal Insulin Demand for Dose Adjustment (NIDDA) study. Diabetes Care. 2011;34:2146-2151.
  43. Bell KJ, Bao J, Petocz P, et al. Validation of the food insulin index in lean, young, healthy individuals, and type 2 diabetes in the context of mixed meals: an acute randomized crossover trial. Am J Clin Nutr. 2015;102:801-806.
  44. Chung M, Ma J, Patel K, et al. Fructose, high-fructose corn syrup, sucrose, and nonalcoholic fatty liver disease or indexes of liver health: a systematic review and meta-analysis. Am J Clin Nutr. 2014;100:833-849.
  45. Ding M, Bhupathiraju SN, Chen M, et al. Caffeinated and decaffeinated coffee consumption and risk of type 2 diabetes: a systematic review and a dose-response meta-analysis. Diabetes Care. 2014;37:569-586.
  46. Jiang X, Zhang D, Jiang W. Coffee and caffeine intake and incidence of type 2 diabetes mellitus: a meta-analysis of prospective studies. Eur J Nutr. 2014;53:25-38.
  47. Lee S, Hudson R, Kilpatrick K, et al. Caffeine ingestion is associated with reductions in glucose uptake independent of obesity and type 2 diabetes before and after exercise training. Diabetes Care. 2005;28:566-572.
  48. Lane JD, Feinglos MN, Surwit RS. Caffeine increases ambulatory glucose and postprandial responses in coffee drinkers with type 2 diabetes. Diabetes Care. 2008;31:221-222.
  49. Robinson LE, Savani S, Battram DS, et al. Caffeine ingestion before an oral glucose tolerance test impairs blood glucose management in men with type 2 diabetes. J Nutr. 2004;134:2528-2533.
  50. Fernandez ML. Dietary Cholesterol provided by eggs and plasma lipoproteins in healthy populations. Curr Opin Clin Nutr Metab care. 2006; 9;8-12

Back to Top