A cornerstone of the ketogenic, or keto, diet is significantly reducing sugar intake. This reduction is crucial for initiating ketosis, a metabolic state where the body primarily burns fat for energy instead of glucose. However, this doesn't necessarily mean sacrificing all sweet-tasting foods. Sugar alcohols offer a potential solution, providing sweetness and texture similar to sugar, but with fewer calories and a reduced impact on blood sugar levels. This makes them an appealing option for those aiming to lower their sugar consumption, particularly individuals adhering to a keto diet.
This article delves into the compatibility of sugar alcohols with a keto lifestyle and identifies which options might be more suitable.
Understanding Sugar Alcohols
Sugar alcohols are carbohydrates with a chemical structure similar to sugar, stimulating the tongue’s sweet taste buds, which adds flavor without extra sugar or calories. Despite their name, sugar alcohols contain no ethanol, nor are they exactly like table sugar. While they occur naturally in small amounts in some fruits and vegetables and are made by your body, most sugar alcohols found in packaged foods are manmade and manufactured. Food manufacturers use these sugar alcohols to sweeten their products while reducing calories, allowing them to market their foods as ‘low-carb,’ ‘sugar-free’ or ‘diabetes-friendly’ without sacrificing taste.
Due to their low calorie contents, sugar alcohols are frequently used to sweeten sugar-free or diet products like gum, yogurts, ice cream, coffee creamers, salad dressings, and protein bars and shakes.
Common sugar alcohols found on food labels include:
Read also: The Definitive Guide to Flourless, Sugar-Free Dieting
Erythritol: Often produced by fermenting the glucose in cornstarch, erythritol possesses 70% of the sweetness of sugar but only 5% of the calories.
Isomalt: A combination of two sugar alcohols, mannitol and sorbitol, isomalt provides 50% fewer calories than sugar and is approximately 50% as sweet. It's commonly used in sugar-free hard candies.
Maltitol: Processed from the sugar maltose, maltitol is 90% as sweet as sugar with nearly half the calories.
Sorbitol: Commercially derived from glucose, sorbitol has 60% of the sweetness and around 60% of the calories of sugar.
Xylitol: As sweet as regular sugar but with 40% fewer calories, xylitol is one of the most prevalent sugar alcohols.
Read also: Comprehensive Guide to Sugar on Keto
Sugar Alcohols vs. Artificial Sweeteners vs. Sugar
It's important to distinguish sugar alcohols from both artificial sweeteners and natural sugars.
Sugar alcohols are sometimes referred to as artificial sweeteners, a category that includes aspartame and saccharin, but they’re actually not the same thing. Though they’re both manufactured, they differ in a couple of key ways. Sugar alcohols have very few calories, and they’re not as sweet as sugar. Artificial sweeteners, on the other hand, are chemicals that provide an intense level of sweetness and no calories.
You can also buy artificial sweeteners as a sugar substitute for baking and cooking and find them in packets at restaurants and coffee shops. Sugar alcohols are commonly used in processed foods.
Sugar is 100% natural, exclusively coming from fruits, plants, vegetables and milk. Though some sugar alcohols come from fruits and vegetables, the ones used in processed foods are artificially produced.
Sugar alcohols have some advantages over regular sugar, including:
Read also: Reboot your health with a 30-day cleanse
Fewer calories: Unlike sugar, which has about 4 calories per gram, sugar alcohols have between 0 and 2 calories per gram. They taste almost as sweet as sugar with about half the calories - or less.
Easier blood sugar management: Unlike regular sugar, sugar alcohols don’t cause sudden blood sugar spikes. They’re considered a low glycemic index food and may cause only a slight rise in blood sugar levels. That’s why they’re used in commercially produced packaged snacks and sweets and are commonly marketed as “good for diabetes.”
Less dental risk: Sugar alcohols don’t react to dental plaque the way sugar does, which means they don’t contribute to tooth decay. You may see the sugar alcohol xylitol as an ingredient in your toothpaste, which helps make it taste better while it’s helping to prevent cavities.
Fewer carbs: Sugar alcohols can fit into a low-carb diet because they’re much lower in carbs and have a lower glycemic index than regular forms of sugar.
How Sugar Alcohols Affect Blood Sugar
When you consume sugar, your body breaks it down into smaller molecules, which are then absorbed into your bloodstream, causing blood sugar levels to increase. Sugar intake is limited on a keto diet, as eating it causes your blood sugar levels to rise. This is an issue, as raised blood sugar levels can make it difficult for your body to remain in ketosis, which is key for reaping the benefits of the keto diet.
Conversely, the body cannot fully break down and absorb carbohydrates from sugar alcohols. As a result, they cause a much smaller rise in blood sugar levels. One way to compare the effects of these sweeteners is their glycemic index (GI), which is a measure of how quickly foods can raise your blood sugar.
Here are the GI values of common sugar alcohols:
- Erythritol: 0
- Isomalt: 2
- Maltitol: 35-52
- Sorbitol: 9
- Xylitol: 7-13
For comparison, white table sugar (sucrose) has a glycemic index of 65. Given that they negligibly affect blood sugar levels, most sugar alcohols are considered to be keto-friendly.
Sugar Alcohols and Net Carbs on Keto
Given that sugar alcohols have a much less significant effect on blood sugar levels, they’re commonly found in keto-friendly products. Furthermore, since they aren’t fully digestible, keto dieters often subtract the sugar alcohols and fiber from the total number of carbs in a food item. The resulting number is referred to as net carbs.
Choosing the Right Sugar Alcohol for Keto
Still, due to the variation in GIs of different types of sugar alcohols, some are better for the keto diet than others.
Erythritol is a good keto-friendly option, as it has a glycemic index of 0 and works well in both cooking and baking. Plus, due to its small particle size, erythritol tends to be better tolerated than other sugar alcohols.
Still, xylitol, sorbitol, and isomalt are all suitable on a keto diet. You may simply want to scale back your intake if you notice any gastrointestinal side effects.
One sugar alcohol that appears to be less keto-friendly is maltitol. Maltitol has a lower GI than sugar. However, with a GI of up to 52, it’s likely to have a more significant effect on your blood sugar levels than other sugar alcohols. As such, if you’re on a keto diet, you may want to limit your intake of maltitol and choose a sugar alternative with a lower GI.
Potential Risks and Side Effects
When consumed in normal amounts through food, sugar alcohols are considered safe for most individuals. However, they do have the potential to cause digestive issues, especially in larger amounts. Side effects like bloating, nausea, and diarrhea have been observed when intake of sugar alcohols exceeds 35-40 grams per day. Consuming large amounts of sugar alcohols may cause digestive side effects, such as diarrhea and nausea.
Additionally, individuals with irritable bowel syndrome (IBS) may experience negative side effects with any amount of sugar alcohols. As a result, if you have IBS, you may want to avoid sugar alcohol completely.
Sugar alcohols have long been considered a safe addition to your diet - in moderation. Studies have shown 10 to 15 grams a day of sugar alcohols are safe. But many processed foods containing sugar alcohols have levels far greater than that threshold.
Emerging research suggests potential risks associated with elevated levels of certain sugar alcohols:
Heart attack and stroke: Circulating levels of both xylitol and erythritol have been shown to be associated with an increased risk for “major adverse cardiovascular events.” That includes a heightened risk for heart attack, stroke and even death. High levels of xylitol and erythritol can send your platelets into overdrive. Platelets are the components in your blood that allow it to clot. Clotting is a good thing if you have an open wound. It keeps you from bleeding out. But when your blood clots inside your body, it’s a recipe for a medical emergency - like a heart attack or stroke. It doesn’t take much either. For example, just one scoop of keto-friendly ice cream contains up to 30 grams of xylitol. Dr. Hazen’s research suggests that’s enough to agitate your platelets and make them more likely to form clots. And the increased risk lasts about four to six hours (or until you eat more xylitol-containing foods.) When you eat foods containing erythritol, the risk can remain for several days. More research needs to be done to understand what the effects are of other sugar alcohols. But based on what we see from xylitol and erythritol, it’s fair to say that sugar alcohols should warrant caution. These compounds are in foods that are typically marketed to people with diabetes, who already have an increased risk for major heart events. And the sugar alcohols in their diets may inadvertently be adding to that risk.
Gastrointestinal (GI) issues: Your body can’t fully digest sugar alcohols, which can lead to some unpleasant GI symptoms when eaten in larger quantities - and they usually happen pretty soon after you eat them. In a 2006 British study, researchers gave participants doses of sugar or one of two types of sugar alcohols (xylitol and erythritol). Those who took xylitol reported bloating, gas, upset stomach and diarrhea. Erythritol appeared to have milder effects on the stomach, only increasing nausea and gas when consumed in large doses. If you eat foods with sugar alcohols several times a day, you could wind up with some tummy troubles on top of raising your risk for heart conditions in the long term. If you notice this happening, use caution or find another sweetener option.
Laxative Effect: In everyday terms, this means that sugar alcohols may make you poop. Again, this is because your stomach can’t absorb sugar alcohols, which can cause them to linger in your intestines and ferment. This effect is most common in children and in adults who:
Weight gain: Sugar alcohols are low in calories and carbs, but, depending on the type, aren’t free of them. So, it’s still possible to gain weight when you’re eating foods that contain sugar alcohols, especially if you eat them in excess. A study of college students found that consuming high levels of dietary erythritol were associated with weight gain - specifically, increased belly fat - throughout their freshman year.
Identifying Sugar Alcohols on Food Labels
Just as sugar lurks behind different terms on food labels, sugar alcohols also have many names. When you see one of these products on a label, here’s what you’re getting:
Xylitol: Xylitol is about as sweet as sugar. It comes from wheat straw and some cereals. On an industrial scale, it’s produced from wood materials or by microbial fermentation. It’s often found in sugar-free desserts and candies. Also frequently found in diabetic candies. Notably, you’ll also find it in some oral care products, like toothpaste and mouthwash because it helps prevent dental carries. The dangers associated with xylitol are related to eating it in large quantities. So, it’s not going to cause negative effects in your dental care (swish and spit) routine.
Erythritol: Erythritol is 60% to 80% as sweet as sugar. While it can be found in small quantities in things like pears, soy sauce and watermelon, on an industrial scale, it’s made by yeast fermentation of corn or wheat starch. One of the fastest-growing sugar substitutes in the food industry, ingesting it as a sugar substitute can raise blood levels more a 1,000 fold, and take days before returning back to baseline levels.
Isomalt: Isomalt is about 45% to 65% as sweet as sugar. It comes from beet sugar.
Lactitol: Lactitol provides about 40% of the sweetness of sugar. Manufacturers make it from milk.
Maltitol: Maltitol is about 75% as sweet as sugar and is made from corn, wheat and potatoes, and catalytic hydrogenation.
Mannitol: Mannitol is 50% to 70% as sweet as sugar. Naturally, it occurs in carrots, olives and asparagus. While some manufacturers make it from seaweed, much is made from hydrogenation of fructose at high temperatures and pressure.
Sorbitol: Sorbitol is about half as sweet as sugar. Naturally, it’s found in apples and pears, but industrially, it’s made from potato starch.
Food and Drug Administration (FDA) doesn’t require food companies to list sugar alcohols on their ingredient lists. Aside from reading the ingredients on food labels, Bissell says you can identify products that may contain sugar alcohols by looking for processed foods that say they’re:
- Keto-safe.
- Diabetes-safe.
- Sugar-free, no sugar or low sugar.
- Artificially sweetened.
- Naturally sweetened or sweetened with natural compounds.
- Low-calorie or calorie-free.
Another dead giveaway that a product includes sugar alcohols is a label that says, “Excessive consumption can cause a laxative effect.” The FDA requires this language on any product that contains added sorbitol or mannitol.