The ketogenic or “keto” diet has become immensely popular in recent years as a way to lose weight and improve health. This low-carb, high-fat diet puts the body into a metabolic state called ketosis, where it burns fat for fuel instead of carbs.
One of the keys to success on keto is limiting sugar intake, but this can be confusing when it comes to sugar-free or artificial sweeteners. Are they allowed? Will they still trigger insulin response? Do they fit into keto macronutrient goals?
Here is a comprehensive look at whether sugar free products can be part of a well-formulated ketogenic diet.
What is the Keto Diet?
The keto diet is characterized by a very low carbohydrate intake, moderate protein intake, and high fat intake. The typical macronutrient breakdown on keto is:
- Carbs: less than 50g net carbs per day, ideally 20-30g
- Protein: 0.8-1.2g per pound of lean body mass
- Fat: Makes up 60-80% of total daily calories
This forces the body into ketosis, where ketones produced by the liver become the main fuel source instead of glucose from carbs.
Ketosis offers many potential benefits including:
- Enhanced weight loss, especially fat loss
- Reduced appetite and cravings
- Improved mental focus and cognition
- Increased and stable energy levels
- Better blood sugar control
To achieve and maintain this fat-burning state, keto requires strict adherence to ultra low-carb eating. This is why questions arise around sugar free foods.
What are Sugar Free Sweeteners?
Sugar free sweeteners provide the sweet taste of sugar without the calories and carbs. There are two main types:
Natural Sweeteners
These are usually derived from herbs plants or fruits. Examples include:
- Stevia – from Stevia rebaudiana plant
- Monk fruit – from Siraitia grosvenorii fruit
- Erythritol – found naturally in some fruits and fermented foods
Artificial Sweeteners
These are synthetic sugar substitutes created in a lab. Some common ones are:
- Aspartame
- Sucralose
- Saccharin
- Acesulfame potassium
So are these allowed on keto or not? Let’s take a closer look.
Do Sugar Free Sweeteners Fit Macros?
One of the first things to evaluate is whether sugar free sweets fit into your target keto macros.
Most sugar substitutes contain very few or zero net carbs and calories. A packet of Splenda, for example, has less than 1g carb and 0 calories.
This means foods sweetened with sugar alternatives won’t take you out of ketosis from a macronutrient standpoint. You can enjoy them and still meet your carb, protein, fat and calorie goals for the day.
Some exceptions are sugar alcohols like maltitol and sorbitol. They contribute 2-3 calories per gram and have a moderate glycemic impact. Net carbs from maltitol should be counted as 50% of total carbs. Still low carb but not zero carb.
Macronutrient Profile of Common Sweeteners:
| Sweetener | Calories/g | Net Carbs/g |
|---|---|---|
| Stevia | 0 | 0 |
| Monk Fruit | 0 | 0 |
| Sucralose | 0 | 0 |
| Saccharin | 0 | 0 |
| Aspartame | 0 | 0 |
| Sorbitol | 2.6 | 2.6 |
| Maltitol | 2.1 | 1.5 |
| Xylitol | 2.4 | 1 |
| Erythritol | 0.2 | 0.2 |
As you can see, most sugar subs fit into keto macros with very minimal or zero carbs and calories. The sugar alcohols contribute a small amount so consume in moderation.
Do Sugar Substitutes Spike Insulin?
A more complex question is whether non-nutritive sweeteners elicit an insulin response, one of the key drivers of fat storage.
Pure sugar substitutes themselves do not raise blood glucose or require insulin to metabolize. However, the taste of sweetness itself can still cause an insulin spike in some cases.
This is because our bodies expect calories when tasting sweetness, so insulin is secreted in preparation. When those calories fail to appear, it may result in hypoglycemia and sugar cravings.
Animal studies have shown this insulin response from sucralose and other sweeteners[1]. However, human data has been mixed:
– Several studies found no insulin response to artificial sweeteners[2].
– Other trials showed a small insulin spike, but less than real sugar[3].
– A 2008 study found sucralose raised insulin levels by 20%, but did not affect blood sugars[4].
Factors like personal metabolism, gut health, and frequency of consumption likely play a role here.
Overall, pure sugar free sweeteners appear mostly safe for keto if consumed in moderation, at least from an insulin perspective. Keep intake to 1-2 servings per day to be safe.
Impact on Appetite and Cravings
Another key consideration is if sugar substitutes promote appetite and cravings, hindering keto weight loss.
This is again an area of some debate based on mixed evidence:
– Rat studies link artificial sweeteners to increased food consumption and weight gain versus controls when fed alongside glucose or on their own[5].
– Several human trials found users of diet soda had higher rates of obesity and metabolic syndrome[6]. Correlation doesn’t prove causation though.
– Other human studies found no difference in hunger, cravings or weight loss for artificial sweetener groups[7].
The bottom line is more research on long term studies in humans is needed to understand potential impacts on appetite and cravings.
To be on the safe side, limits sugar free sweets to a few times per week at most. Rely on healthy low carb sweeteners like stevia and monk fruit as much as possible.
Are There Any Other Concerns with Sugar Substitutes on Keto?
Most sugar substitutes appear relatively safe on keto if used in moderation. But there are a few other considerations:
Gut Health
Some animal studies and anecdotal reports indicate artificial sweeteners like aspartame, saccharin and sucralose may alter gut flora, resulting in symptoms like cramps, bloating, diarrhea for sensitive people[8].
Monk fruit, erythritol, and stevia are likely safer options with less impact on gut microbiome.
Cancer Risk
Early studies raised concern of increased cancer risk in rats from sachharin. However, this was debunked and saccharin was deemed safe by the National Cancer Institute[9].
No links between stevia, aspartame or other sweeteners and cancer risk have been found in human trials.
Tooth Decay
While sugar free products cannot feed oral bacteria like refined sugars, the sweet taste can still increase acidity in the mouth temporarily. Rinsing with water after consumption is wise. Going overboard with sugar free candy and soda may increase risk of cavities[10].
Tolerance and Allergies
A small percentage of people have sensitivities to sugar alcohols like erythritol, xylitol, and maltitol. This may cause digestive upset. Start with small amounts and see how you tolerate specific sweeteners.
For most people, the only side effect is possible stool changes from sugar alcohols.
The Verdict: Smart Use of Sugar Free Products is Fine on Keto
Based on available evidence, sugar free sweeteners are unlikely to disrupt ketosis or slow fat burning if used wisely. The ideal approach is:
- Focus on natural sweeteners like stevia, monk fruit, erythritol. They likely have fewer side effects than artificial versions.
- Limit to 1-2 servings of sugar free foods per day max.
- Avoid pairing sugar free foods with sugary foods as this spikes insulin more.
- Don’t let sugar free foods trigger increased cravings for carbs and sugar.
- Check labels for hidden carbs and sugar alcohols.
- Make sure you count carb and calories from sugar alcohols correctly.
As with most things in nutrition, moderation and smart choices are key. Sugar free products can fit into a well-formulated keto diet without sabotaging progress.
References
1. Sucralose affects glycemic and hormonal responses to an oral glucose load. Diabetes Care. 2013 Sep;36(9):2530-5.
2. Acute, short-term, and chronic effects of artificial sweeteners on glycemia, insulin, and gut hormones: a narrative review. Nutrients. 2021 Jul; 13(7): 2344.
3. Effects of stevia, aspartame, and sucrose on food intake, satiety, and postprandial glucose and insulin levels. Appetite. 2010 Aug;55(1):37-43.
4. Sucralose affects glycemic and hormonal responses to an oral glucose load. Diabetes Care. 2013 Sep;36(9):2530-5.
5. Artificial sweeteners produce the counterintuitive effect of inducing metabolic derangements. Trends Endocrinol Metab. 2013 Sep;24(9):431-41.
6. Fueling the obesity epidemic? Artificially sweetened beverage use and long-term weight gain. Obesity (Silver Spring). 2008 Aug;16(8):1894-900.
7. The impact of non-nutritive sweeteners on hormone release and appetite in humans. Physiol Behav. 2016 Dec 1;164(Pt B):381-385.
8. Artificial sweeteners and metabolic dysregulation: Lessons learned from agriculture and the laboratory. Rev Endocr Metab Disord. 2021; 22(2): 241–251.
9. National Cancer Institute: Artificial Sweeteners and Cancer Overview
10. Effects of artificial sweeteners on metal lability and dental biofilm acidogenicity. J Appl Microbiol. 2015 Aug;119(2):705-12.
