For anyone on a low carb or Keto eating style, finding healthy, low glycemic, and low carb sweeteners that actually taste good is the equivalent of a culinary treasure trove. When deciding between different low carb sweeteners, there are four main things to consider:
- Is it natural or artificial?
- Is it safe, and what are any potential side effects?
- Will it impact blood sugar and/or ketone levels?
- And most importantly, does it taste good?
Although artificial sweeteners (i.e. aspartame, saccharin, sucralose) won’t directly raise blood sugar levels or affect ketosis, their long term safety concerns are a major sticking point and are, therefore, not considered the healthiest options. This is why we recommend choosing natural over artificial low-carb sweeteners as part of a well-formulated keto diet.
The four most popular natural low carb sweeteners are:
- Monk Fruit
Stevia is one of the most popular natural, no-carb, calorie-free sweeteners currently on the market. Stevia is the common name for the extract stevioside from the leaves of a shrub known as Stevia rebaudiana Bertoni.
Practical Things to Know About Stevia
- No Impact on Blood Sugar: Stevia cannot be metabolized by the body, so it has no impact on blood sugar levels—its Glycemic Index (GI) is 0.
- 300 Times Sweeter than Sugar: Stevia’s sweetening power is up to 300 times sweeter than regular table sugar (sucrose) by weight, which is why often just a very small amount of Stevia adds enough sweetness.
- To Avoid The Bitter Taste, Look for the Reb D form of Stevia in the Products you Purchase: The structure of glycoside molecules plays a key role in determining the sweetness or bitterness of Stevia. The steviol glycoside rebaudioside D, or Reb D form of Stevia, is around five times sweeter and two-thirds less bitter than dulcoside A (Reb A). Reb D is the formulation that is used by several name brand stevia producers, such as in Splenda Naturals. If you have been noticing any bitterness in products you’ve purchased that use Stevia, it may be because they are using the cheaper, and more bitter, Reb A form of the molecule.
- Can be Used for Baking: Stevia is heat stable, so it can be effectively incorporated into baked goods. Because of its sweetness-density, stevia is usually combined with other sweeteners, such as erythritol, to provide the required “bulk” needed for use in cooking/baking. This combination also serves to boost its overall flavor, a discovery known as “Sweetener Synergy”.
- No Reported Side Effects: There are no reported side effects of stevia—including allergic reactions— and this sweetener is not known to be contraindicated for any medical conditions. Stevia is globally approved as safe for use by leading medical, scientific and regulatory authorities.
- Doesn’t Count Toward Total Carbohydrate on a Label: Because of its highly concentrated sweetness, a single ingredient sweetener containing 100% stevia will list its total carbohydrate content (per serving) as zero.
Health Benefits of Stevia
- Antioxidant, Anti-Inflammatory, & Antimicrobial Activity: The high levels of sweetening compounds in stevia extracts, (i.e. stevioside, Reb A through F, and dulcoside), are thought to have antioxidant, anti-inflammatory, and antimicrobial activity, inhibiting the growth of certain bacteria and other infectious organisms.
- Can Help Lower Blood Sugar: Stevia and its related compounds have properties that lower blood sugar levels following meals in people with type 2 diabetes. These same compounds have also been shown to lower blood pressure in those diagnosed with elevated levels (no effect seen in those with both normal blood sugar/blood pressure levels).
- Anti-Tumor & Cancer Fighting Properties: Stevia extracts have been shown to exhibit anti-tumor and cancer-fighting properties in research studies using animal models.
Cons of Using Stevia
- Stevia might be bitter or unpleasant tasting for some, especially if they are new to this sweetener. However, by choosing a variety that contains Reb D, the bitterness should be much less detectable.
- Even when using the less bitter Reb D form of Stevia, you can still notice some bitterness if you use too much of it – so find your own personal sweetspot for how much stevia you use.
- Buyer beware: Some forms of less expensive Stevia are mixed with other sweeteners or bulking agents (e.g., maltodextrin, dextrose, cane sugar), which contain hidden carbs (calories) and could have an impact on blood sugar levels.
Erythritol is one of a number of naturally-occurring sugar alcohols, or polyols, each with varying levels of sweetness, calorie values, and ranges of impact on blood sugar levels.
Practical Things to Know About Erythritol
- No Impact on Blood Sugar: Erythritol has no impact on blood sugar or insulin levels. The molecular structure of erythritol allows the body to absorb erythritol but not metabolize or break it down. Amongst the sugar alcohols, erythritol also provides the lowest Glycemic Index (GI of 0-1) and it contains less than 0.20 calories per gram, as compared to 4 calories per gram in regular sugar.
- 60-80 Percent of the Sweetness of Sugar: Erythritol has 60-80 percent of the sweetness of sucrose, or table sugar.
- Improved Digestibility Compared to Other Sugar Alcohols: Erythritol is the easiest sugar alcohol for our body to digest, with up to 90 percent of it absorbed by the small intestine before it can enter our large intestine (colon) and cause digestive upset. Sorbitol and maltitol, on the other hand, even in small doses, have been found to be much harsher on the stomach and digestive system.
- Can be Used for Baking: Like Stevia, Erythritol is heat stable and can be used for baking. Erythritol is widely used as a bulk sweetener in low-calorie foods and provides added sweetness, texture, and bulk when used in combination with other zero-calorie natural sweeteners.
- Doesn’t Count Toward Total Carbohydrate on a Label: Because of its negligible carbohydrate content per gram weight and its zero impact on blood sugars, Erythritol is the ONLY sugar alcohol that can be completely subtracted from the grams of Total Carbohydrate listed on the Nutrition Facts label.
Health Benefits of Erythritol
Perhaps there are no pros to choosing Erythritol. Other than providing a carb-free, natural alternative to sugar, Erythritol does not appear (at present) to have any direct therapeutic health benefits. It is, however, one of the must gut-friendly sugar alcohols out there.
Cons of Using Erythritol
- Symptoms of GI distress, especially after consuming foods with erythritol in higher quantities.
- A ‘cooling taste’ may be experienced after eating foods containing erythritol.
Also known as Luo Han Guo, monk fruit is a member of the gourd family and was originally cultivated nearly 800 years ago by Buddhist monks (hence its name) in Southern China. Like Stevia, monk fruit has been used in traditional herbal medicine for centuries. It is only recently that monk fruit has been transformed from a medicinal fruit into a healthy sweetener.
Practical Things to Know About Monk Fruit
- No Impact on Blood Sugar: Monk fruit extract, like stevia, contains no calories or carbohydrates, and has no impact on blood sugar levels (GI of 0).
- 150-200 Times Sweeter than Sugar: Monk fruit extract, derived from the juice of the fruit, is 150-200 times sweeter than regular sugar.
- Fuel for the Microbiome: The compounds that give monk fruit its sweetness are called mogrosides. These are absorbed in the lower gastrointestinal tract (colon), where microbes in our gut use them as a source of energy, boosting our healthy gut flora.
- No Bitter Aftertaste: Monk fruit extract appears to have a better taste profile (no bitter aftertaste) than its low-carb natural sweetener counterpart, stevia.
- Some Potential for Allergies: Because monk fruit is a member of the gourd family of fruits and vegetables, which includes melons, pumpkins, and squash, any allergies to these foods will increase your risk of a monk fruit allergy.
- Can be Used for Baking: Like stevia and erythritol, monk fruit is stable at high temperatures, and can be used in baking. Because of its highly concentrated sweetness, monk fruit is usually blended with other natural no-calorie sweeteners such as stevia and erythritol (serving as a bulking agent).
- Doesn’t Count Toward Total Carbohydrate on a Label: Like stevia, monk fruit is a highly concentrated sweetener, and a single ingredient sweetener containing 100% monk fruit will list its total carbohydrate content (per serving) as zero.
Health Benefits of Monk Fruit
- Antioxidant Activity: The mogroside compounds in monk fruit have been shown to exhibit powerful antioxidant activity, which protect against mitochondrial and DNA damage.
- Anti-Tumor Activity: These same mogroside compounds demonstrate anti-tumor activity by promoting increased levels of a tumor-suppressing gene.
- Especially Beneficial to Individuals with Type 2 Diabetes: Mogroside can especially be of potential benefit to individuals with Type 2 diabetes by stimulating pancreatic insulin secretion.
- Helps Limit the Growth of Fat Cells: Mogrul, a major circulating form of mogroside in the blood, limits the growth of fat cells and restricts fat production by inhibiting enzymes which can convert stem cells to fat cells.
Cons of Using Monk Fruit
- High cost. Purchased in its pure form (as a single ingredient), monk fruit is very expensive.
This one is the “newest sweetener on the block” and offers yet another reason to kick your sugar habit to the curb. Allulose, also known as D-psicose or D-allulose, has the same chemical formula as fructose, but contains a different structure. This structural anomaly prevents our body from metabolizing allulose.
Practical Things to Know About Allulose
- Closest Taste Profile to Real Sugar: Due to its close proximity to fructose, allulose has the same taste profile as regular sugar.
- No Impact on Blood Sugar: Because allulose is not metabolized by our body, it does not impact blood sugar or insulin levels. In fact, during the process of obtaining FDA approval, researchers found that allulose can actually blunt the glycemic (blood sugar) response of other carbohydrates when consumed together at the same meal.
- 70 percent of the Sweetness of Sugar: Allulose contains only a fraction of the calories of regular sugar (0.2 calories per gram vs 4 calories per gram) with 70 percent of its sweetness.
- Can be Used for Baking: Allulose is heat stable and has the texture of regular sugar, making it ideal for baking. Allulose also works synergistically in combination with other concentrated natural sweeteners, such as stevia and monk fruit. Together, the sweetener blend results in a more potent level of sweetness than that of the individual sweeteners – again, something that we refer to as “Sweetener Synergy”.
- No Reported Side Effects: There have been no reported side effects caused by allulose, but the FDA recommends doses below 35 grams per day (0.5-0.6 g/kg) in order to avoid gastrointestinal discomfort.
- No Longer Counted as Sugar: Following a recent FDA decision, allulose no longer needs to be counted towards the amount of “Total Sugars” or “Added Sugars” on the new Nutrition Facts label. One of the key changes to the new label as of January 2020 requires the listing of “Added Sugars” under the subheading of “Total Sugars”.
- Doesn’t Count Toward Total Carbohydrate on a Label: Because allulose is not recognized by the body as a carbohydrate or metabolized as energy, any gram amount of allulose listed on the label can be subtracted from the grams of Total Carbohydrate on the Nutrition Facts label.
Health Benefits of Allulose
- Blunts the Rise of Blood Sugar After Meals: Allulose, or D-psicose, blunts the rise of blood sugar following a meal in individuals with pre-diabetes – it also has an after-meal blood-sugar lowering effect in non-diabetics as well. These qualities make allulose ideal for both managing and preventing diabetes.
- Can Help Reduce Abdominal Fat: A study of a large group of overweight adults demonstrated that allulose was able to significantly reduce their abdominal fat and waist circumference.
- Can Help Treat Fatty Liver: Research using animal models shows that dietary supplementation with allulose can positively impact obesity-related fatty liver without exercise therapy or additional dietary intervention.
Cons of Using Allulose
- High cost. Allulose is expensive, but as market competition continues to expand, and as the production of allulose increases through the process of bacterial fermentation, its limiting cost factor will likely improve.
We have come a long way from the days of pink, yellow, and blue packets as the only means to reduce our consumption of sugar and satisfy our sweet tooth. The entry of low-carb, all-natural sweeteners has transformed the sugar-substitute landscape and will likely help to phase out, or replace, the use of artificial sweeteners. For anyone on a ketogenic diet, the choices of natural, safe, and taste-appealing low or no-carb sweetener options have never been greater. There is no longer a need to “desert your dessert” – anyone on a ketogenic diet can officially ditch the carbs without compromising taste or health. Deciding which of the above four sweeteners is right for you is a personal one, as both individual health goals and taste buds are unique. Also keep your eye out for more low carb natural sweetener options likely to be introduced to the commercial market in the near future.
Written by Mary Paley
Mary Paley, RDN, LD, CDE, is a Registered Dietitian with a Master’s Degree in Nutrition and Dietetics at the MGH Institute of Health Professions. Her current focus is on the benefits of ketogenic diets for both obesity and diabetes management. Having worked in a number of institutional settings for 30+ years, she has interacted with tens of thousands of people with various health disorders, the vast majority within the triad of obesity, diabetes, and heart disease.