“Clinically shown to help manage blood glucose levels.” “Helps reduce excessive food consumption.” “Nutritional support for blood-sugar stability.” “Avoid blood sugar lows and highs.” “May help you lower A1C levels.”
Wouldn’t it be great if a specially formulated snack bar or shake could do all that? These days, grocery and drugstore shelves offer a dizzying array of energy bars and other products designed to offer convenience, good nutrition, and sometimes more. A number of products are specifically targeted to people with diabetes, and, as seen from the advertising slogans listed above, many manufacturers claim that their products offer benefits beyond providing a quick snack — and there’s some evidence that some do.
It’s long been known that keeping blood glucose levels within a fairly narrow range helps you to feel better generally and perform better both physically and mentally. More recently, research has suggested that frequent sharp rises and falls in blood glucose level may be associated with the development of cardiovascular disease in some people with diabetes. “Stabilizing” your blood glucose — or preventing highs and lows — is therefore a worthwhile goal.
The nutrition bars, shakes, and some other products currently marketed to people with diabetes may help you achieve this goal by either preventing hypoglycemia (low blood glucose) or by preventing high blood glucose, particularly after meals. In either case, however, the product you choose to use must be incorporated into your overall meal plan, not just added on, and it should be consumed at an appropriate time. It should be low in saturated fat and, ideally, contain no trans fat. And you should assess its effectiveness at improving your blood glucose control with frequent blood glucose monitoring.
Products that contain uncooked cornstarch can help to prevent hypoglycemia because of the way the body absorbs this type of starch. Unlike some other forms of carbohydrate, which the body quickly breaks down and converts to glucose, potentially causing spikes in blood glucose level, uncooked cornstarch is broken down and absorbed very slowly. It does not, therefore, cause a sudden rise in blood glucose level but rather causes a prolonged, lower rise. Interestingly, cooked cornstarch does not have this effect; it produces a faster, higher blood glucose rise.
Because the taste of uncooked cornstarch alone is unappealing, food manufacturers have created products that contain it along with other ingredients to mask the flavor and provide other nutrients. (Cornstarch alone provides virtually no nutrients other than carbohydrate.)
In research studies, it has been shown that eating a bedtime snack containing uncooked cornstarch reduces the incidence of hypoglycemia overnight in people with Type 1 diabetes who follow an intensive insulin regimen. A small study that used continuous glucose monitoring to document the incidence and duration of hypoglycemia showed that hypoglycemia occurred at a rate of 2.8% when people with Type 1 diabetes ate an uncooked-cornstarch–based snack bar at bedtime, and at a rate of 22% when they ate their regular bedtime snack. In addition, people with Type 2 diabetes who ate a bedtime snack bar containing uncooked cornstarch had fewer incidents of elevated blood glucose at midnight and had lower fasting (before-breakfast) blood glucose levels the next morning. The reason for the lower morning fasting blood glucose level is unclear, but it may be due to improved insulin release from the pancreas or more controlled glucose output from the liver.
One widely available product that contains uncooked cornstarch as a key ingredient is ExtendBar, a brand of nutrition bar that was developed by pediatric endocrinologist Francine Kaufman, who was searching for a way to help her patients stabilize their blood glucose level over extended periods. In her research, she found that mixing a relatively small amount of uncooked cornstarch with particular amounts of fat, protein, and other carbohydrates resulted in a substance that was slowly absorbed over nine hours. Her formulation is now the basis of ExtendBar snack bars, as well as ExtendCrisps, which are crispy, baked, savory snacks, and ExtendShakes, powdered beverage mixes.
Since they can help prevent hypoglycemia, products containing uncooked cornstarch may be useful in a number of situations. Eaten before bedtime, they can lower the risk of hypoglycemia during the night. As a between-meal snack, they may help to control both blood glucose level and appetite since they are digested so slowly. And eaten before exercise, a snack containing uncooked cornstarch can aid in preventing late-onset post-exercise hypoglycemia. This occurs when muscles continue to replenish their glucose stores hours after physical activity, leading to a sometimes-surprising drop in blood glucose level as much as 8–12 hours after exercise.
Choosing a cornstarch product
If you decide to try a cornstarch-based bar, crisp, or shake, pay close attention to the variety you choose and the details on the Nutrition Facts food label. These products do contain calories, and some of the carbohydrate may need to be counted in your meal plan.
ExtendBars come in two varieties, both of which contain about 150 calories per serving and are sweetened with sugar alcohols. (Sugar alcohols are a type of carbohydrate that in most cases is incompletely digested and absorbed in the intestine, so they provide fewer than 4 calories per gram. An exception to this is glycerine, which is classified as a sugar alcohol but is completely metabolized and provides 4 calories per gram.) The “Crunch” variety contains 30 grams of carbohydrate and 10 grams of sugar, while the “Delight” formula is sugar free, containing 20–22 grams of carbohydrate and 0–1 gram of sugar.
The maker of ExtendBars suggests that if you are counting your carbohydrates — whether it’s to help you manage your meal plan or to determine if an adjustment to your insulin is appropriate — you should count only the carbohydrates that have a short-term effect on blood glucose level. These carbohydrates are referred to as “faster-acting” or “net” carbs. The remaining, “slower-acting” carbohydrates are broken down and converted to glucose so slowly that they have minimal effect on blood glucose level.
In the ExtendBar Delight formula, the carbohydrate from the fiber, glycerine, maltitol, and uncooked cornstarch converts slowly and has a minimal effect on blood glucose level. Therefore, only 1–2 grams out of the total grams of carbohydrate in the Delight formula have a short-term effect on blood glucose. In the Crunch variety, the carbohydrate from uncooked cornstarch, maltitol, and fructose is slower-acting; as a result, only 10–11 grams of the total carbohydrate have a short-term effect on blood glucose level.
Individual packets of ExtendCrisps provide 120–130 calories and 16–17 grams of carbohydrate. The manufacturer suggests that only 8–9 of the total grams of carbohydrate have a short-term impact on blood glucose.
ExtendShakes, when prepared with water, provide 110 calories and 12 grams of carbohydrate. The manufacturer suggests that only 2 of the total grams of carbohydrate have a short-term impact on blood glucose. (If the mix is prepared with milk, the calories and grams of carbohydrate in the milk must be counted as well.)
Cornstarch-based bars retail for about $1.60 each, but volume discounts and free shipping may be available if you order them online through the manufacturer. To see if you like them before ordering a large supply, ask your diabetes care providers if they have any samples for you to try, or just purchase a few at a supermarket or drugstore (Walgreens carries them).
To see what effect a cornstarch-containing product may be having on your blood glucose control, monitor your blood glucose levels, and compare the results on days you use the products to results on days you don’t. As always, check with your diabetes team about the best way to incorporate cornstarch-based bars, shakes, or other products into your diabetes treatment plan.
Resistant starches and fiber
Snack bars and other food products that contain resistant starches and fiber can help to prevent high blood glucose after eating. This is because resistant starches and fibers are incompletely absorbed in the intestine, so they provide less than 4 calories per gram — the amount in “normal” carbohydrates — and have less of an effect on blood glucose level. (In contrast, uncooked cornstarch is slowly, but nearly completely, digested in the small intestine.) Some foods — for example dried beans and whole grains — naturally contain resistant starches. When manufactured resistant starch is added to a food, it is often called “maltodextrin” on the label.
While products containing resistant starch are digested slowly, they are less useful than cornstarch-based bars for preventing nighttime hypoglycemia, because their blood-glucose–raising effects last for only about three hours.
One brand of products that is marketed to people with diabetes and that contains resistant starches is Glucerna. The Glucerna product line includes a variety of sizes and flavors of snack bars, as well as cereals, shakes, and snack shakes with similar formulations.
Researchers have completed several studies to determine the effects of these types of products on people with diabetes. One such study compared the effects of eating a Glucerna bar with those of eating a common breakfast bar (with a similar calorie and nutrient content) in adults with Type 2 diabetes. It showed that blood glucose level rose less after the Glucerna bar than after the common breakfast bar.
Other research comparing diabetes meal and snack bars to standard nutrition bars has also shown that the diabetes bars containing resistant starches produce a smaller change in blood glucose level, both immediately and over the next four hours. The effect of eating Glucerna bars has not been studied in children.
To see what effect one of these bars has on your blood glucose level, check it before eating a bar, then check again one to two hours afterward and again three to four hours afterward. You will get the best information if you eat the bar by itself, with no other food or caloric beverages; otherwise, it will be difficult to sort out the effects of the bar from the effects of the other food or the beverage.
Choosing a resistant starch product
As with any new product you include in your meal plan, take note of the nutrition information marked on the package. Glucerna bars come in three sizes with similar formulations but different nutrient values:
A Glucerna meal bar typically contains 210–220 calories, 34 grams of carbohydrate, 2 grams of fiber, and 7 grams of sugar alcohol. The meal-size bar is meant to occasionally replace a meal and may be supplemented with a salad and fat-free milk.
A Glucerna snack bar typically contains 150 calories, 25 grams of carbohydrate, 1 gram of fiber, and 10 grams of sugar alcohols. The snack-size bar is designed to be used as a substantial snack and may be helpful for days when you are busy and need something quick and convenient.
A Glucerna mini-snack bar typically contains 80 calories, 12 grams of carbohydrate, less than 1 gram of fiber, and 4 grams of sugar alcohols. The mini-snack bar can be used instead of dessert or as a between-meal snack.
Approximate retail prices for Glucerna bars are $1.87 for the meal-size bar, $1.35 for the snack-size bar, and 70 cents for the mini-snack size bars. Money-saving coupons are available on the manufacturer’s Web site. To see if you like them before you buy, check to see if your diabetes educator has samples you can try.
Glucerna cereals are a source of whole grains. A 3/4-cup serving of the Crunchy Flakes ‘n Raisins variety contains 110 calories, 28 grams of carbohydrate, and 5 grams of fiber.
Glucerna shakes are sold in 8-ounce, reclosable, plastic bottles, while Snack Shakes are sold in 8-ounce metal cans. The shakes provide 200 calories, 26–27 grams of carbohydrate, and 5 grams of fiber per serving. The snack shakes provide 140 calories, 19 grams of carbohydrate, and 3 grams of fiber per 8-ounce serving.
Another component of energy bars and shakes that may help with blood glucose control is protein. Protein does not directly raise blood glucose level the way carbohydrate does, but it does cause the pancreas to release insulin when consumed with carbohydrate (in people with functioning pancreases). Protein also tends to have a satiating, or satisfying, effect, so you may feel fuller after a high-protein meal.
One product that boasts a high protein content and is marketed specifically to people with Type 2 diabetes is Boost Glucose Control, a nutrition shake made by Nestlé Healthcare Nutrition, Inc. The shake also contains a variety of slowly absorbed carbohydrates — namely tapioca dextrin (a breakdown product of tapioca starch), inulin (a type of soluble plant fiber), and guar gum (a type of carbohydrate derived from beans).
According to the manufacturer, a study conducted by Nestlé researchers in people with Type 2 diabetes showed that drinking Boost Glucose Control resulted in a blood glucose peak below 180 mg/dl, which is within the after-meal range recommended by the American Diabetes Association.
Boost Glucose Control shakes are sold in 8-ounce, reclosable, plastic bottles and are intended to be used as a snack or small meal. Each single-serving container provides 190 calories, 16 grams of carbohydrate, 16 grams of protein, and 3 grams of fiber.
Fat tends to slow the digestion of carbohydrate and therefore to slow the rise in blood glucose level after eating a snack or meal that contains both. This is one of the reasons the makers of nutrition bars and shakes include some fat in their products. Another is that certain fats — in particular, monounsaturated fats, polyunsaturated fats, and a type of polyunsaturated fat called omega-3 fatty acids — appear to be beneficial to heart health, so products that contain them generally mention that fact prominently in their marketing materials.
Enterex Glucose Control, for example, which markets itself as a “nutritionally balanced snack drink,” notes that it contains only oils high in monounsaturated fat such as canola oil (which also contains omega-3 fatty acids) and high-oleic safflower oil. An 8-ounce can of Enterex Glucose Control provides 237 calories, 9 grams of fat, 27 grams of carbohydrate, and 3 grams of fiber.
Vitamins and minerals
Some bars and shakes marketed to people with diabetes contain multiple vitamins and minerals, and some carry label claims suggesting that certain vitamins and minerals can help to control diabetes or its complications. At this time, there is no evidence that specific vitamins or minerals improve blood glucose control, although research is ongoing on this subject.
However, there is the risk of getting too much of some vitamins and minerals if several bars or shakes containing large amounts of vitamins and minerals are consumed during the day or if a multivitamin is taken in addition to a bar or shake containing high amounts of vitamins and minerals. If you are already getting 100% of the recommended dietary allowance of most vitamins and minerals from a multivitamin, you do not need another 100% from a nutrition bar or shake.
Keep in mind…
The different diabetes nutrition bars, shakes, and other products aren’t necessarily interchangeable. Their different formulations will have different effects on your blood glucose.
None of the products described in this article should be used to treat hypoglycemia. They all contain ingredients that slow their absorption, so they won’t raise your blood glucose level as quickly as needed in that situation.
Cornstarch-based bars are generally used at bedtime to prevent overnight hypoglycemia. They could also be useful during the day for people who don’t experience or notice symptoms of hypoglycemia (called hypoglycemia unawareness). Some health-care providers recommend these bars as a snack to prevent the hypoglycemia that can occur after drinking alcohol.
Although cornstarch-based bars have not been studied during pregnancy, they may help prevent overnight hypoglycemia and the incidence of morning “starvation” ketones in pregnant women. When eaten as part of breakfast, both cornstarch and resistant starch nutrition bars can help reduce the after-breakfast rise in blood glucose that is common during pregnancy with diabetes.
When choosing a diabetes nutrition bar or shake, consider any food allergies you may have. Many of these products contain ingredients such as milk, peanuts, soy, and wheat.
If you are trying to lose weight, nutrition bars and shakes can be convenient, portion-controlled options for meals and snacks. However, keep in mind that none of these products is designed to be a sole source of sustenance. Work them into your meal plan along with other nutritious foods. (For more information about the role of diabetes nutrition bars and shakes in weight loss, see “Can They Help You Lose Weight?”)
Keep your diabetes team informed, and carefully monitor your blood glucose if you begin using diabetes nutrition bars or shakes for help with blood glucose or weight control.