What is aspartame?
Aspartame is the artificial sweetener found in products such as Nutrasweet®, Equal®, and Sugar Twin®. It was approved by the US Food and Drug Administration (FDA) in 1981.
Since then, it is commonly found in products such as ice cream, breakfast cereals, chewing gum, prescription medications, and nutritional supplements, and Diet Coke loses its sweetness when exposed to high temperatures and is not used in cooking or baking.
Aspartame has 4 calories per gram – the same as sugar. However, since aspartame is about 200 times sweeter than sugar, only very small amounts are needed.
The result is a sweet taste with significantly fewer calories and carbohydrates.
So…is aspartame keto?
Before we go any further, let’s get to the point.
Aspartame is not the best sweetener to use on a keto diet.
Fortunately, there are now better options available.
Going on a cola diet every now and then won’t completely disrupt the keto diet. But if you take the time to build healthy habits, aspartame isn’t the best sweetener to use.
Is aspartame safe?
Aspartame has been extensively studied to evaluate its effects on the human body. Much of the available research indicates that it is safe for the general public, within reasonable limits. (1)
The Food and Drug Administration (FDA) has set the Acceptable Daily Intake (ADI) for aspartame at 50 mg per kilogram (23 mg per pound) of body weight per day. (1)
For example, 12 oz. Diet Coke contains about 180 mg of aspartame. Therefore, an average person weighing 150 pounds would not need to consume more than 19 Diet Cokes per day to stay within the ADI. Easy enough!
But still – is aspartame on keto a good idea?
Why it’s best to avoid aspartame on keto
Unlike some safety studies, there is scientific research that shows that taking aspartame regularly can have unwanted side effects.
A 2018 analysis looked at some of the negative effects of aspartame. They found that this sweetener can act as a chemical stress agent, increasing the hormone cortisol. (1)
This can then contribute to insulin resistance, which is the very thing many of us on Keto are trying to reverse or prevent.
In animal studies, aspartame caused hormonal imbalances, resulting in increased appetite and food intake, decreased energy intake, and increased fatigue. (1)
Other studies have found that aspartame can have negative effects on the gut microbiome, leading to the growth of disease-causing bacteria. (1These changes in the gut can worsen glucose tolerance. (1)
All of this leads to worse health outcomes, and difficulty staying in ketosis.
But it doesn’t end there!
A 2017 scientific review found that even at doses considered acceptable, aspartame can cause oxidative stress and damage to cell membranes, leading to organ inflammation. (1)
Chronic inflammation is linked to a wide range of potentially fatal health problems, including heart disease, Alzheimer’s disease, cancer and type 2 diabetes.
More human studies are really needed to help settle the controversy. In the meantime, it might be a good idea to explore less controversial options for a good solution.
Aspartame vs. sucralose: which is better?
Sucralose joined the commercial sweetener field in 1992 and received FDA approval as a general-purpose sweetener in 1998.
It is an artificial sweetener and a sugar substitute made by a chemical process that combines molecules of chlorine and sucrose (table sugar). The result is a product that is about 600 times sweeter than sugar, yet contains no calories and carbohydrates.
Sucralose is sold under the brand name Splenda® (although not all Splenda® products contain sucralose). It is also an ingredient in thousands of other products.
It may come as a surprise that sucralose products, such as Splenda®, usually contain additional ingredients that are not particularly keto-friendly. This little yellow packet also contains dextrose and maltodextrin, which add even more sweetness and mass, making it taste like sugar.
Is sucralose safe?
The Acceptable Daily Intake (ADI) of sucralose has been set at 5 mg/kg body weight per day in the United States. For a person weighing 150 pounds, this is roughly equivalent to 8 cans of sucralose-sweetened soda.
Again, this is a limit that most people have no problem staying at.
But as with aspartame, sucralose has been the subject of extensive study, and the results have been controversial.
The makers of sucralose claim that it can be heated without losing its sweet taste. It is sold in bulk (with added maltodextrin) for use in cooking as an alternative to granulated sugar.
Unfortunately, studies have shown that sucralose produces harmful compounds when exposed to high temperatures. (1And the 2) so it’s probably not the best sweetener to use in your Keto cookie recipes after all.
Sucralose also disrupts the gut microbiome. It kills good lactobacilli and bifidobacteria strains, and reduces the total amount and diversity of microbes that live in the gut. (1)
A 2013 study found that sucralose had a negative effect on blood sugar and insulin, causing both to increase more than the control group. (1Since an increase in blood sugar will put you out of ketosis, this poses problems for keto dieters.
Conclusion: Aspartame vs. Sucralose
Both are very low in calories and carbohydrates. Both can cause problems in maintaining ketosis and a healthy microbiome. Nobody is good to bake with.
We recommend the different sweeteners altogether. Fortunately, there are great products available to make cooking and shopping for keto-friendly foods that much easier.
Best sweeteners for keto
The sweeteners we like for keto people are the best in taste and have the fewest unwanted side effects:
All of these are safe and well tolerated at high temperatures, which makes them great for baking. Available research indicates that they tend to have neutral or positive effects on the gut microbiome. It is also associated with stable or improved blood sugar levels.
Frequently Asked Questions
1. Is aspartame keto friendly?
No, aspartame is not keto friendly. It can indirectly increase blood sugar and insulin, which may interfere with ketone production. Additionally, studies show that it may have a bad effect on overall health if taken regularly.
2. Does aspartame affect ketosis?
Aspartame may knock you out of ketosis. You can do the test yourself by measuring ketones in your blood before and after you take aspartame.
3. Does aspartame keep you awake?
Yes, there are several ways aspartame can keep you awake when you prefer to sleep.
It acts as a chemical stress agent, which increases the hormone cortisol. Too much cortisol can interfere with sleep. (1)
Aspartame can also disrupt the function of the neurotransmitter in the brain, causing decreased serotonin activity. This also can cause sleep problems. (1)
4. Does aspartame contain formaldehyde?
Yeah. When aspartame is digested, it is broken down into a number of components that include aspartic acid, phenylalanine, and methanol (a substance that might be toxic on its own!).
Methanol is broken down into formaldehyde and formic acid.
Now, to be fair, we are routinely exposed to natural sources of formaldehyde, and in fact our bodies produce a certain amount of the substance.
However, it is not something we really want more, when there are much better options for a great solution!
Say no to aspartame on keto
Aspartame (and sucralose!) should be avoided on keto. While these artificial sweeteners are low in carbohydrates, there are other factors that make them all wrong for those seeking to improve their health.
Instead, try one of the sweeteners we recommend. Stevia, Erythritol, Monk Fruit, and Swerve are all good options for enjoying the sweeter things in life while cutting out carbs.