At first glance sweeteners may seem like the perfect addition to a low-carb or ketogenic eating plan. They provide the sweetness of carbohydrates without any digestible (net) carbohydrates to our diets. When we look more closely, however, we find that sweeteners have a variety of effects on our bodies. While some of these effects may be desirable others are very undesirable. Sweeteners impact our palate (taste buds), biomarkers (such glucose and insulin), and/or our gastrointestinal system in a variety of important ways.
Let’s begin by defining sweeteners. A sweetener is a substance that produces a sweet taste on our palate (taste buds). Sweeteners are classified as caloric (provide calories in the form of carbohydrates) or non-caloric (do not provide calories). Caloric sweeteners include honey, maple syrup, agave nectar, coconut palm sugar, corn syrup, and fruit. These items provide sweetness along with carbohydrates. Some sources provide vitamins and minerals however most sweeteners do not. This means they have little to no room in a low-carbohydrate or ketogenic eating plan. Non-caloric sweeteners include artificial sweeteners, natural sweeteners, and sugar alcohols. Artificial sweeteners can be made from plants or sugar. They are much sweeter than sugar and can be used in small amounts to produce a large degree of sweetness. Artificial sweeteners are often combined with maltodextrin or dextrose, both sugars, as a carrying agent. (“Raw” versions of these sweeteners do not contain these ingredients). Examples of artificial sweeteners include sucralose (Splenda), aspartame (Equal), saccharin (Sweet n Low), and acesulfame potassium. Natural sweeteners include both monk fruit and stevia. Monk fruit, or luo han guo, is a fruit found in China. This sweetener is 400 times sweeter than cane sugar. Despite its sweetness it is virtually calorie-free. Stevia is produced from the plant Stevia rebaudiana and is 300 times sweeter than sugar. Sugar alcohols occur naturally in plants, however they are not completely calorie-free. Every gram of a sugar alcohol contains 1.5 to 3 calories per gram (versus 4 calories per gram for sugar). Examples include erythritol, maltitol, mannitol, sorbitol, and xylitol. You may quickly notice that there is an “-ol” ending found in each sugar alcohol. This ending provides an easy way to recognize an ingredient as a sugar alcohol. Unlike artificial sweeteners most sugar alcohols are less sweet than sugar. They may cause gastrointestinal distress, such as gas, bloating, constipation, and diarrhea, due to the fact that they are not completely absorbed. These sweeteners are often found in sugar-free, diabetic, and “keto-friendly” products.
Although these sweeteners provide sweetness with fewer or no calories they also come with specific effects. First, they lack nutritional value and do not resemble natural foods (foods you can grow, hunt, or fish) in any way, shape, or form. This is especially true of artificial sweeteners. This means they were never consumed by our hunter gather ancestors and do not provide any significant source of nourishment for our bodies. Second, despite the fact that they contain fewer or no calories many sweeteners still stimulate an insulin response. This works against our efforts to create benefits found by following a low-carb or keto eating plan. Third, they continue to stimulate a sweet taste on our palate. This may lead to a desire for sweet foods that may lead to sugar or other carbohydrate cravings. Remember, we are looking to “re-program” our palates to appreciate and desire the taste of natural foods. Consuming sweeteners, especially in high amounts and/or frequently, may undermine this goal and lead us to seek processed food items that are high in sugar or other refined carbohydrates (examples: regular soda, desserts, bread, pasta, etc). This may make it much more challenging to create our new, healthy way of eating for the long-term.
In more recent years two additional groups of ingredients have made their way into the food marketplace: functional fibers and rare sugars. Functional fibers occur naturally in small amounts in plants and are added to foods to increase their sweetness and nutrition. Examples include isomaltooligosaccharides (IMOs), inulin, and soluble corn fiber. These ingredients are very sweet and undergo minimal digestion by our gut enzymes. Inulin and soluble corn fiber do not raise glucose or insulin levels, however, IMOs raise both glucose and insulin levels (similar to slow-digesting oatmeal). Inulin benefits our gut bacteria, however it has been shown to cause gastrointestinal distress in very small amounts (5 to 10 grams) in first time users. Over time the effects tend to diminish with continued intake. Soluble corn fiber does not have these effects and benefits both gut bacteria and appetite (helps you feel full). Allulose, a rare sugar, is found in small amounts in nature. It tastes sweet but is minimally digested. It may cause gastrointestinal distress, however, and is not recommended for use in significant amounts (more than 10 grams).
If you are seeking to successfully follow a low-carbohydrate or ketogenic eating plan your best bet is to truly change your palate. Steer clear of sweeteners when planning and selecting your foods. Experiment with different recipes, seasonings, and herbs to find flavors that you enjoy. Train your taste buds to appreciate the abundant flavors found in naturally occurring foods. When you choose to embrace the bounty found in nature and experience positive, life-giving benefits you just might find that sweetened items no longer have the appeal they used to.
Reference: The Ketogenic Bible by Dr. Jacob Wilson & Ryan Lowery, PhD(c), 2017.